Fixing hydraulic disk brakes, what to check first? I have a 10-year old bike, fitted with hydraulic disk brakes. The bike has been actively used for around 4 years only though.

Recently, my brake levers started to have more and more "play" before the bike actually starts braking. A kind of a "dead zone" where nothing happens, just like if there was not enough oil.

I went to the store to fix it, twice, but it keeps coming back. They say something may be stuck ("bourrage" in french, as ugly as it sounds). They told me they bled the brakes, but at this point I'm not sure anymore.

So now I'd like to fix this myself, once and for all.

The brakes are the only thing I've been afraid to fiddle with, so far, so that's why I'm coming here for advices.

Is there any "fixing your hydraulic disk brakes 101" or equivalent? A guide I could follow to check things in order. Shall I check brake pads first, then oil, then... A flowchart would be lovely!

tl;dr: What to check first to fix hydraulic disk brakes?

If they are SRAM/Avid hydraulic brakes, you're screwed. The DOT 5.1 fluid attacks the o-ring seals, and makes constant issues. Storing the bike for a while, upside down or vertically, will also cause issues. If they are Hayes or Tektro, same deal with the the DOT 5.1. This means don't spend money on them, replace with a Shimano M596 or better. They use mineral oil, which is much better with rubber, moisture, and expansion. They also have the fewest issues of any other mainstream product out there, by far.

Now, SRAM currently allows a no-questions asked full replacement warranty with all current models. I don't recall how far back it applies. If 10 years, maybe not. But, still worth a try. Ask a reputable LBS to make the call to SRAM on brake warranty. Thing is, you're getting another SRAM brake, which will do the same thing again.


Can I use a Shimano RD-M735 rear derailleur with road shifters like the SL-6400 (7s) or the SL-6401 (8s)? I'd like to set up an old school touring/rando bike.
Do Shimano road and mountain bike components of that era (7 and 8 speed) share the same cable pull ratio? I know the RD-M735 is 7 speed, using it as an 8 speed derailleur shouldn't be an issue. But I'm not sure when it comes to shifter compatibility.

Yes, it will work perfectly. Every pre-10-speed Shimano MTB rear derailleur will index with every road shifter prior (chronologically) to the beginning of 11-speed road, except for 7400/7410 Dura Ace.


What to prepare for a long distance ride (1600km) I will be riding my bicycle from Czech Republic to London this April. Even though I cycle quite frequently, this is my first time I will be doing such a long distance.

I am not doing this for charity, awarness or whatever super meaningful reason (even though if you know some good cause I dont mind to slap a sticker on my jacket...). Simply I got new bike, moved to London and when thinking about how to get it there I thought why not to just ride it.

Here is map of my planned trip:

As I planned it, it should take 13 days, 1600km, average of 120km a day. I don't think I am aiming for a crazy goal.

To the question:

To all of you who done some long distance around europe, what would you recommend for a gear to take with me? I have vague idea about what I want to take, but I probably missed something so better to ask.
Would you recommend bringing tent and a sleeping bag? I am not against sleeping outdoor at all, but after all we are in europe and not middle of sahara, I think I will always be able to find somewhere to sleep, eat etc.

Any advice from experienced long rider would be much appreciated.

Update 1

The Bike I am going to be riding

More info about the bike

This bike comes with very thick tires, I will be changing for thinner flatter tyres. something around 1.95 should be comfortable enough

I took part in a charity ride from Scotland to Italy in June last year, and that was made a lot easier with the use of a support team to help carry everything. Since you are going it alone, you need to consider quite a lot of things:

Directions

It's fine planning a route, but they often don't go to plan. Always be prepared to make alterations at the last minute. A detailed road map of the area / GPS device is essential for this.
Know roughly where you're going to end up at the end of each day. Plan ahead and maybe pre-book your accommodation. Most places allow you to reserver a room for free and pay when you leave, so it comes at no initial cost. If you don't make it to a given town, find somewhere else to stay. You suggest camping in a tent - although feasible, bear in mind the amount of kit you may already be carrying.

Nutrition

Undertaking long mileage takes its toll on your energy levels, so its important to replace the calories and replenish water loss. You can carry sandwhiches or even pop into cafés, but another alternative is the use of energy gels and flapjacks etc. These are easy to carry and provide enough fuel to keep you going.
Hydration is really important, so carrying water or some other hydrating fluid is essential. Try mixing it with energy drink powder to hydrate and keep your energy stores up.

Spares / Tools

Long-distance cycling takes it's toll on your bike, but also increases the likelihood of hitting a problem along the way.
Carry a set of bike tools such as a chain link tool, spanners, hex keys to help you make adjustments and repairs along the way.
Inner tubes, tyre levers and a puncture repair kit (and a pump!) are also vital. You can always find a petrol station or another cyclist to help, but be prepared and be self-sufficient with repairs.

Clothing

Take a variety of clothing to help with the different weather conditions. There's nothing worse than getting into wet clothes when you could have had a dry set to hand.

Waterproofs

Hot-weather gear
Base layers

If I think of anything else I will add it to the list, but these are some of the main things to consider that I can think of.


Unicycle touring -- how common? A couple of days back, on our way to California (in a car), my wife and I passed a unicyclist going the other direction, uphill, on a fairly challenging section of Route 66.  (I think we were in Arizona.)  The guy had on his back a LARGE backpack that, based on my experiences Scouting, probably weighed 40-60 pounds, maybe more.  No idea how far he had traveled so far, but presumably he was out for a multi-day trip (on roads that would exceed 6% grade for miles at a time).

What are the records for unicycle travel?  Are there any unsupported cross-country trips on record?  How common is unicycle touring?

Unsupported unicycle touring is not very common because it doesn't work very well - you really need to carry more stuff than can comfortably be carried in a backpack while unicycling, which limits the amount of time on the uni, which in turn limits how far you can go. As well, unis are slower than bikes which further limits distances. Towing a trailer kind of defeats the point of a uni, and makes the whole process very difficult. But that's what you need if you want to carry more than a days food and water. That said, people regularly manage 50-60km a day, so it is possible to tour.
These two managed 3500km across Australia, and unicycle forums are where you'll find most of the details.

A unicyclist on a record breaking tour of North and South America has reached British Columbia, after biking more than 22,000 kilometres on one wheel.
Cary Gray of St. Louis, Mo., set off on his epic journey on July 1, 2013 and has already spanned 11 countries: U.S., Canada, Mexico, Belize, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, and Colombia.
In Panama, Gray broke the Guinness World Record for Longest Unicycle Journey,

(via CBC News)

The same guy via Pinterest
Lots of the "unicycle touring" I've been able to find is fully supported - it's one or two people on unicycles, followed by at least one motor vehicle carrying all their gear. This guy rode 15,478km across Australia and also claims to hold the Guinness world record (that site is all about the fundraising effort).
(edit) Also, the legalities can be difficult - in many countries unicycles are technically not allowed on the road, or the rules are bizarre (unicycles are bicycles, so riders must keep at least one hand on the handlebars at all times, for example, or must have two brakes). In Australia and New Zealand, for example, they are sometimes "bicycles" and other times "wheeled recreational devices" which must be ridden on the footpath. I've not seen those rules enforced in either country, but they exist. I suspect if a unicyclist was hit by a car they'd be treated even worse than a cyclist in the same position.


Shimano Di2 Minimum Junction Setup I am planning out a Di2 setup with the Ultegra 6870 series, but I don't need to run a front derailleur. I am making a 1x11 setup. Is it possible to connect the shift level (I am using the ST-R785 levers) directly to Junction B, so I don't need a Junction A at all?

I know for internal batteries, a Junction A is required for charging, but with an external battery, it shouldn't be necessary. Does Junction A do anything else essential? It'd be awesome if someone with a Di2 setup (especially an Ultegra 6870) could test this too.

According to Slowtwitch Shimano needs one junction A in the system otherwise it won't work.

You can skip junction B.

It may cause some interesting wiring.

The 6700 series (EW6770) junction may make things smaller/easier.

This is the same answer for all current e-tube di2 systems. (6700,6800,9000)


What bmx logo brand is this? What bmx logo brand is this ?

It has a lower case b or upside down p and a right-side up p in the shape of a rocket.

The logo on the hub in the picture matches the logo on the hub of a Premium Products wheel See the middle picture of the three on this page.

This may be an older version of the logo. The current version is similar but rougher looking. It seems to be a face with horns.


Do you automatically have to replace your chainrings once your chain reaches 1 % chain wear? My chain was badly worn. 1.0+ % wear. There is no visible shark toothing or extreme spacing on chainrings. Is there a chance I can get away with not replacing the chainrings, or does the amount of chain wear automatically necessitate that I replace them?

I think that one rule of thumb I saw asserted that if you replaced promptly, you could get 2-3 cassettes per chain, and 2-3 sets of chainrings per cassette. I'm not able to provide a concrete source for this right now. However, the fact is that chainrings do wear more slowly than cassettes because they have more teeth.
I think very likely that your cassette needs replacement, and I would do that preemptively. I would not replace your chainrings right now, unless they have had several prior chains that also got to a high level of wear. For smaller chainrings, I would probably lean slightly more towards preemptive replacement.


How/where can I find replacements for these 'wheel bearing caps'? I have started the restoration of a bike picked up from the bins. The bike has taken some abuse. The rear wheel axle was broken, same for the two "bearings" caps or dust seals. I am not sure how to name these. I am providing pictures here for illustration https://imgur.com/a/fKflsyx
It was really to get a replacement for the bearings and the axle, but that cap piece - maybe because of not knowing its name - I am not able to see it for sale anywhere. I am not sure how standard or custom these pieces are. The hub has no brand or logo. The bike is a carrera zelos if this helps.

Metal dust shields would be the common name to the extent there is one. The usual protocol is to handle them with care and never remove them, because they're difficult to replace. The OEM hub manufacturers don't produce a vast number of different ones, so one option can be finding a bike shop with bins of used parts or dead wheels and trying to cannibalize some that match. Wheels Mfg does produce some cones that come with them, and there are generic axle kits that come with random sized ones, but getting it to work is all kind of a hail mary, especially if you need to order them. There are no standards as such for their ID, OD, depth, etc.
As long as they're not torn, working them back into shape looks possible from the pictures. They don't have to be pretty. One approach is finding a socket that's the right size and smacking them down flat again, then working the edges into shape with a hammer and the socket on the other side to act as a mandrel.
If you do find some to transplant, use a vise or suitably sized deep socket to provide support on the flat side, then gently tap them off the cone you found them on and onto the new one. You usually have to go back and adjust the depth a bit manually to make it the right height off the seal interface and prevent rubbing.


How to choose MTB bike tyre: hookless, tubular or clincher? I don't know the difference between hookless tire, tubular tire and clincher tire. When I choose the tire type how to make a professional choice? I want to know which tire type is best for me.

You should use the tyres that fit the rims on your bike. If you were a professional you'd use whatever your sponsor told you to, so that's a bit of a side issue.

Tubulars are back in the MTB world, but they're still rare and it's unlikely your bike has them. I suggest not buying a tubular wheelset, let your sponsors do that when they decide it's a good idea.

Hookless rims have some advantages but not to the point where I would throw away hooked rims to buy them. That assumes you're running tubeless, the advantages of a hookless composite rim with tubed tyres are pretty imaginary.


Single speed to multi-speed conversion with internal gear hub I currently have a single speed 52m Crew District.

I got it as a commuter once I got moved closer my workplace.  I live in a fairly hilly area and I am thoroughly missing the option to downshift and give my legs a break on the way back.

Current gearing is 46 x 16 (freewheel) 700cx25 gators, rear brake only, Omnium 165mm cranks. The District is listed as a track bike and geometry.

I heard it is possible to add gears without a dérailleur by using an internal gear hub.

My LBS seem unreliable and I've gotten different answers. Are they right to try to sell me on a stock multi-speed hybrid or just confused about not using a dérailleur?

Which brings me to the internal hub gear wheels. Are they a gimmick, work "meh", or extremely functional? Any experience with them? I'm confused about the axle measurements, where they are or how to find out.  Does anyone have know if the Soma-Iggy will fit the District's rear spacing and if so what would be better: 3 speed or 5?

Any info would be greatly appreciated.

Are they a gimmick, work "meh", or extremely functional? Any experience with them?

I ride internal gear hubs (IGH) only, because they are extremely functional. I definitely prefer them over any deraileur system.
Why? Because IGHs have much better shifting than chain-shifts:
Ever stopped at the lights with your chain-shift in the wrong gear? Well, duh, you'll have to accelerate with the wrong gear in place. Not so with IGHs: You select the new gear, move your pedals back and forth once (only the pedals, not the bike!), it says "click", and you are ready to rock.
Ever found you needed to shift a gear lower on a steep ascend, and didn't have much speed to spare for the shifting? With an IGH, you select the lower gear, you release the pressure from the pedals for a split second (and I really mean "split", like a quarter second, or so), it says "click", and you are in the correct gear again. No need to reduce force until the chain has fully moved to the correct sprocket.
On a similar note, when you shift up during acceleration, IGHs virtually eliminate the shifting breaks in power output. It feels like driving a tip-tronic car over a manual shift car. Once you are used to the "click-click" shifting performance, you won't want to go back to deraileurs.

The downsides of IGHs compared to chain-shifts are:

They are a tad less efficient. That's why racers never use IGHs, they need the last percent of performance. However, that's definitely not an argument for commuting and touring.

The spread of gears is a bit more limited. IGHs usually span a factor of approximately 3 between lowest and highest gears, chain-shifts for mountain bikes have a much higher range. I.e. on steep slopes you may find that you are missing a gear or two with an IGH. But it's still much better than having only one gear, isn't it?

Update:
After getting some experience with a Rohloff Speedhub, I feel that I must mention that it deviates from my description above in some points:

Shifting is not deferred, it takes exactly as long as you need to turn the controlling grip into the new position. This also works under some load, but the more pressure you have on your pedals, the harder it becomes to turn the grip.

Efficiency is significantly higher than with cheaper IGHs I've ridden.

Gear spread is significantly wider. Most other IGHs max out at roughly 300% spread, the Rohloff gives 500% spread.

There are other top category products that I have not tested, and which also deviate significantly. Most importantly the NuVinci which does not even have gears, it can produce any transmission factor over its entire range. I imagine that this can be a very sweet feature, and I did consider it for my investment. In the end, I decided that a high gear spread was more important to me than continuous shifting.
Of course, the Rohloff is the most expensive product in the market, so you must decide for yourself whether the above is worth the investment of a little more than thousand Euros. Cheap second hand IGHs may be obtained for 25 Euros, and they are already a very good choice. So, if you are on a tight budget, take something like the SRAM 7-Speed, and be happy with it. You should only consider the top products if the money is not really the issue. But if you decide to invest the extra money, I have found that it was indeed worth it. In my case, I mostly enjoy the higher efficiency and the small increment between the gears.


Will a 2x with a clutch RD be just as effective as a 1x with a clutch and narrow-wide chainring on an mtb? I am continuously dropping my chain on my enduro mtb rides (currently 2x). The rear derailleur that my bike is currently running is a deore non-clutch.

My chain will normally drop after riding rock gardens, jumps, and drop offs.

My friend  says that even if i get a clutch version of my current derailleur I will still drop my chain and that I should just convert to 1x. But a 1x conversion is more expensive and will lower my gear range. So I would like to know if a clutch 2x will have the same effect?

Note: My bike was new 2017 but has had hard use, the bike is a feul ex 5

It will help 2x, though 1x is going to hold chain better. I think you'll still see an improvement with a 2x setup due to added chain tension. When I upgraded the drivetrain on my full suspension to use a 10spd Shimano Deore clutch derailleur it didn't drop chain nearly as much if ever. Make sure you have your chain shortened to the appropriate length as that's one of the biggest factors causing chain slap and jumps is having a chain that's too long.

A 1x would likely work better if you switched to a narrow/wide chainring that prevents jumps though. I almost never drop a chain on the 1x setup with a race face narrow wide ring. The front chainring does a lot to stop the chain from slipping off due to the tooth profiles that really keep the chain engaged. I'm running a cheaper 10 speed setup on my hardtail with a sunrace 11-42 casette with a 10spd sram x-9 clutch derailleur and it works very well and was a cheap upgrade vs a whole new 11spd.


Average lifetime for 26inch spokes I've been riding my bike for about a year and a half now and the back spokes are starting to snap, 2 now. I want to know when was this bike bought from the original owner since the spokes are stock spokes and it is second hand, it would be easy to know. All I do is just wheelies and bunny hops so maybe it might wear off more faster. Also, should I replace the spokes asap?

From the info you've given it's hard to tell how old your bike/the spokes are.

If the spoke tension is too low/if there is too big a difference in the tension of the spokes in the wheel this can cause premature spoke failure due to uneven force distribution over the spokes in the wheel. Make sure to have proper spoke tension/tension distribution to prevent premature spoke failure.

To answer your other questions:

1) Yes the wheels will not last as long when doing bunny hops and other such 'stunts' (such as riding down stairs, jumping off things etc.)

2) You should replace your spokes as soon as possible, if you don't and keep riding there is a significantly higher chance of more spokes braking (since the force is distributed over less spokes)


Teams in the Age of Specificity Specificity, periodization, power meters - training for competitive cycling has changed a lot over the last  few years.

I am wondering about the effects of the movement towards training alone on the group dynamics of cycling teams, specifically local or regional amateur teams.

I've been lucky to have grown up around cycling and a few cycling teams.  As I recall, training used to be focused on frequently riding together not only for getting in the hours and miles in on the bike but for practicing pacelining and tactics.  Now, more and more people are training using power meters and following very specific workouts that are built around their idiosyncratic FTP and power levels.  This level of specificity makes it difficult to coordinate group rides that are relevant to the highly specified training plan.  For example, if my coach tells me to go out and do two 20 minute intervals in the Tempo Power level across a two hour ride with some 3 minute VM intervals, unless I have a riding buddy whose Tempo and VM levels are really close to mine we really can't ride together effectively.

So I'm curious how, or if, others are dealing with this as well?  How has the cycling team, as a social construct, had to adapt to advances in training method and technique?  Does anyone have any tips on how to build and maintain comradery and team-unity while also allowing folks the flexibility to train according to their own plan?

When most of your training is comprised of specific workouts then obviously you will be training solo a majority of the time.  The best way to gel as a team is to do a lot of races together.  Set aside a day each week for a group ride and don't limit it to just your team, make it competitive. This is a good time to work on your sprints, etc. A week long training camp early in the season is good, too.


Can I expend same or less effort riding a mountain bike than road bike? I know nothing about engineering.

I feel like I can expend the same or even less effort riding a mountain amd a road bike (if going slowly) but feeling is not reliable, so I hope to get some insight on this matter.

Let's assume the mountain bike has a hard fork, hard tail, really thin tires.
At same price as the road bike. The two bikes are going for the same distance on a smooth road, with no wind. I don't know if climbing and decending make much difference.

What I guess is, if I am going slow, so the aerodynamics of a road bike will not make much difference, won't I using almost same effort to cover the same distance?
Gear ratios affect fuel consumption, so can I manage my gear ratio and speed to save total work I expend? Will a mountain bike will require less work to cover the same distance?
When riding in the city where you have to frequently stop and start, does a road bike need more effort than mountain bike since it has higher ratio gearing?
Is there some way to test this without a lab environment? I can't find a way to measure how much work I'm doing, and total work I expended.

Please feel free to educate me, I just want to know more.

Where I got this weird idea was from my wife:

She got a hard tail hard fork DIY XC bike, with carbon frame and fork. it was decently light, at about 10KG, slick tire with high pressure and very narrow. It cost bit more than US$1600.

But, she only rides it if we are going out town. She commutes with a US$45 lady bike, she said it was not much difference riding this bike, if under 4km.

I tried her lady bike, it was pretty easy riding short distance in the city, but very hard at longer distance on account of riding posture, and very small bike -- riding slowly of course.

Whelp, how to answer this? Depends what you mean by 'less effort' I guess.

I'll give the short answer up front. Road bikes are more efficient (therefore less effort to ride) than mountain bikes on road surfaces. We know this because road bikes have been optimized for speed and efficiency for a couple of hundred years. Geometry mess, riding position, wheel size, tire width and gear ratios all contribute to this.

To address points 2 and 3 about gearing. Everybody has pedaling cadence and gear ratio that is most efficient for them. A casual rider would use a lower gear ratio, a pro racer will use a much higher one. The availability of lower ratios does not make a bike more efficient (as long as they are low enough for the rider), Road bikes have enough gears to allow selection of an efficient ratio and their lowest ratios are sufficient to allow easy acceleration from a stop. Mountain bikes have lower ratios than road bikes to allow riding up steep inclines (and to pull their greater mass around).

Is there a way to test this? Yes. The advent of (relatively) affordable and accurate power meters make analysis of rider performance available to even casual riders.


Is it possible to install a 1x11 drivetrain on an old MTB? I have an old Stumpjumper from 1984. It has the original 3x5 drivetrain with friction shifting. I'm intrigued by the idea of converting to a 1x11 drivetrain, but I don't know what factors to consider regarding the feasibility of doing this. At least on paper, it looks ok since doing something like 36T x 10-42T would give me about the same range of gears I currently have. Is it even possible to do 1x11 on an old bike like this? How do I determine this?

Update: I should have pointed out that my frame has 126mm rear spacing. It is steel, so it can accommodate a standard 130mm road hub or be cold set to take a standard 135mm MTB hub.

I did half of this - my late 80s 3x5 speed freewheel with nuts got upgraded to a 3x7 freehub with quick release, because the wheel was available.  Turned out the freehub was actually 8 speed, so I could have gone as high as 3x8.

However its already hard to get the wheel into the frame - I don't think you'll fit a wheel and an 11 speed cassette in there.

Also the QR has to be checked after every ride.  I've had the back wheel rotate slightly in the dropouts and it rubs on the chainstay, which means it moves at the power stroke.  I did not cold-set the frame, so the dropouts are not parallel | | they are now slightly \ / which allows a little movement and eventually the QR comes loose enough to move.  Depending on conditions this might be 10 to 100 km of riding to back off loose.

The rear thumb shifter will need to change, that's a given.  I got away with using the same rear deraileuer mechanism and wire, but had to change the lever to a 7 speed indexed one.

You'll also need to change the chain.  5 speed chains are quite thick and may bind up in a 6/7/8 cassette.

Mine cost $50 for a cassette, $3 for some spacers, $40 for the thumb shifter, and another $40 for the new 6/7/8 speed chain.   That was probably too much, but the freehub and chain needed doing anyway.

Summary  this is probably not worth doing unless you get the replacement parts really cheap (ie free or almost free.)


Make a 3-gear bike go easy on uphill I want to see how can I make this 3-gear bike go easier on uphill. It has an internal gear hub. I don't know much about bikes but I'm thinking if I can merely replace the hub for one with 14 gears (Rohloff Speedhub) and also, not sure, but can I change the single chainring at the cranks (front) with another one that will have two chainrings so that I get a smaller one to make uphill even easier.

PICTURE: REAR gear

PICTURE: front gear

Replacing a hub is not a "simple" procedure -- it, at a minimum, involves relacing the rear wheel, probably with different sized spokes (whose size you must accurately determine).  Relacing is not beyond the abilities of a competent backyard mechanic, but is a skill that needs to be learned.

To add a second chainring you must install some sort of device to take up the chain slack.  A front derailer does not do this, so either a rear derailer or some specialized device.

It would be far easier/cheaper to purchase a new (or "new to you" used) bike.

What you MIGHT be able to do is to replace your front chainring with a smaller one.  Or it's vaguely possible that there is available a replacement larger sprocket for your rear hub.  Of course, either of these would slow down your high gear.


How hard is it to disassemble and reassemble a bottom bracket? I ride an SE Lager. It's a pretty cheap and crappy bike. I've had to replace pretty much everything on it due to wear/breakage.

The only area I haven't tackled is the bottom bracket. I can confidently remove/replace/tune all other parts of the bike, but I'm not sure what is involved in the bottom bracket. I'm pretty keen to just pull it apart and check it out, even if it doesn't need replacing right now, so that I'm confident I can do it when it does need replacing. Plus I'm curious and think it'd be fun :)

According to the spec, the bottom bracket is "Euro cartidge sealed bearing w/Alloy Cups". This doesn't seem very informative to me.

Questions:

Will I need any special tools to remove and replace the bearings?
What should I look for when I do get it apart?
How would I go about getting replacement bearings? Do I need to take the whole bike to the LBS or can I tell what I'd need (size/specifications) without needing the bike there?

Any time you see "cartridge" or "sealed" to describe a bottom bracket that means it's not serviceable - you throw it away and buy a new one. Or in some (expensive) cases, replace individual bearing races. The wikipedia Bicycle Tools page has more information. I'm using amazon below to give you an idea of prices.

You will need the appropriate tool to remove the cranks, and another to unscrew the cups that hold the BB in place. Both are readily available but cost about the same as getting new BB fitted. If you want to accumulate tools you could use this opportunity to buy them but it's something that many people decide to get done in a bike shop because it's rare and much easier with a proper work stand.
The problems with a worn BB will be obvious without dismantling anything. If you pull a sealed BB apart it's unlikely you'll be able to reassemble it. The key is how much slop there is in it. If there's too much, it needs replacing. Too much is a judgement call.
The measurement that matters is the spindle length. This is easy to measure once you have it out of the bike but hard to do before then because the cranks cover the bit you're measuring. If you're lucky it will be written somewhere that you can see without pulling it out, but usually the label is somewhere that is inside the BB shell when it's on the bike. Note that they come in 2.5mm increments, so you only need to measure to +/- 1mm.

The easy way is to take it to a bike shop. It's not instant even with the right tools, but you need to apply considerable force to get the cranks and BB off the bike, making it an ugly operation at home. It can be done, but it's not fun. They will pop the old BB out, read or measure the spindle length then try to upsell you from the bottom of the range Shimano BB to however much you're willing to pay. Realistically it's something you'll probably not detect, but the UN54 ones are IMO a good balance between really cheap and just good enough to justify the extra cost (they cost about $US20). You can spend $US200+ on a Phil Wood if you like (they are much shinier).

Also, most bikes come with British BB's, and yours is one of them. Other options are French, Italian and ... read more here (that describes the thread and diameter of the cups).

Edit: one final note. Bottom brackets commonly use both left hand and right hand threads. Again, pedalling the tool forward tightens the part, pedalling backward loosens it. At least with British and Italian BBs, with French they're both right hand threads. French BB's exist to teach us why left hand threads are used on BBs that work.


Shifter cable cut deep groove into the rear derailleur casing I have an old Shimano RD-M760 DEORE XT Rear Derailleur, where shifter cable cut a deep groove into the guiding steel tube. Here is a picture:

Is that tube replaceable? I think that groove is a contributing factor to too much friction in the cable system, which makes downshifting sluggish or skipping gears.
EDIT
Here is a wide angle picture to make my description more clear. The shifter is in the lowest gear (largest sprocket):

and a closeup with adjusting barrel and the cable removed:

The tube with a groove cut into it, is not a back end of the adjusting barrel, it is a separate part. I don't see a way to easily remove it, but it does rotate in place. Maybe I should rotate it 180 degrees, so the cable doesn't sink into the groove anymore. OTOH, the groove is so smooth and nicely shaped as if it is a part of the design. Is it, though?
EDIT 2
It seems that the groove is not a part of the original design. Here is a picture of an old Shimano RD-M760 from Ebay, showing just a slight indentation on this part nowhere near the depth I have on mine:

I was able to rotate the grooved tube 180 degrees with a flat screwdriver wedged into the groove. I cleaned the area and applied a bit of Crazy Glue around the tube. The shifter cable is now in contact with the unworn part of this tube and excessive friction in the system is gone.


Cheap import lights VS branded lights There are a lot of blog posts about cheap import lights (like SolarStorm etc) and how they perform. What is not clear to me is why they are so cheap. I know their battery packs are low quality, but that by its own doesn't justify the price difference. Even replacing their battery pack with a EU/UK made, their price caps at around £35, which is less than half of the cheapest branded light with similar output. What are the shortfalls of these kind of lights?

I run a bike light testing and review site called The Bike Light Database which started as a series of blog posts for the Bicycles Stack Exchange community blog. I've personally tested dozens of lights, and have read lots of info online about countless more. I also speak with lighting companies regularly, have visited a bike light factory in person, and have experience in manufacturing engineering (albeit in a different industry).

Simply put, most cheap imported bike lights are not safe. The batteries and chargers are the biggest safety issue, although the overall design of most of these generic lights is inherently flawed as well. I'll address the batteries first because that's the foremost issue.

The battery safety issue

Most high-powered rechargeable bike lights (and flashlights) use 18650 batteries.  These are a standard size and voltage, and are interchangeable if the device is built in such a way as to allow access to the battery cells. They're found in everything from lights to electric cars to laptops. Standard 18650 batteries have a nominal voltage of 3.7 V, and a fully charged cell is about 4.2 V. Most people consider any voltage below 3.2 V to be unsafe. Capacities go up to around 3600 mAh, but are usually somewhere between 2300 and 3200 mAh. As of spring 2016, there are no commercially available over 3700 mAh, so if you see anything labeled 4000 mAh immediately dispose if it in a safe manner; it's a fake and probably dangerous.

It's important to understand that these batteries hold a lot of energy, and if released in an uncontrolled manner, will explode, burn, release explosive vapors, and yes burn your house down. Used safely, they are an awesome technology which has enabled the high-powered lights with long runtimes available today. These too-cheap-to-be-true Chinese products do not use the technology safely though.

You can get "unprotected" or "protected" 18650 cells. A protected cell has a tiny circuit board on the top which monitors the cell voltage and ensures it doesn't get too high or low. It prevents overdischarge, overcharging, and short circuits. Unprotected cells are considered safe to use in lights designed for them as long as you aren't using more than two, preferably in series. Cells should also be charged individually or in matched sets to ensure the voltage is the same for all cells in a pack. Otherwise, if one cell is already charged and another is not fully charged, the charger could over-charge the full cell causing it to fail.

The batteries sold with these cheap lights tend to be the lowest possible quality to achieve the desired price point. Even the "replacement" battery packs are often of dubious quality. For example, I took apart one such battery pack for a review of a generic Cree U2 "5000" lm light (widely marketed as the Solarstorm X2). Here is a picture of the battery pack:

Two of the cells are dummies - they aren't actually wired such that they could deliver any power. That's "OK" though because the voltages of those cells were 0.0 and 0.3 V - far below the safe cutoff of 3.2 V. The other two cells were mismatched, at 4.0 and 3.8 V. While those voltages are in the typical range, you always want your battery voltages to match. This pack was likely constructed from recycled laptop batteries, with the two disconnected cells being completely dead batteries which were added to give the pack heft and feel like it was legitimate. None of these are protected cells.

Not all cheap imported bike lights are this bad, but the problem is that you don't know how bad it'll be until you actually get it. Quality control is practically non-existent, and because hundreds of vendors sell visually identical products it's impossible to be certain if you're getting a "good one" or not. Make sure to avoid like the plague anything with "fire" in the name, like UltraFire or TrustFire. These brands are known to be widely counterfeited and often dangerous.

Design flaws

Suppose you buy a replacement battery pack which you trust – although again, I'm not sure how you would trust one without opening it to see for yourself. There are still a number of design flaws with these products:

The specifications are almost universally exaggerated, often by 2-5x. I talk about this in more detail in this Outdoors.SE post.
Poor voltage regulation. On these generic lights the output usually drops as the battery voltage drops. Some brand name lights do this too, but you can get brand name lights with good battery voltage regulation.
Cheap material and poor build quality. These lights are built to be as cheap as possible. You'll see terrible hand-soldering jobs, lights that aren't even water resistant, LEDs with inadequate thermal management, plastic lenses instead of optical glass, etc.
The optics quality are typically horrid. You get a very bright hot spot, with uneven spill. This ruins your night vision with the bright spot while not giving you enough light to the sides to see well. You can get diffusing lenses for some models, but the result is a hot bar instead of a hot spot... it's not a significant improvement.
The mounts are weak and hard to use. These lights usually have either a wimpy rubber band mount, or an enormous, over-designed plastic clamp contraption. Neither is convenient if you ever want to remove the light quickly so it doesn't get stolen while your bike is locked up. Speaking of which...
The disconnect cable between the battery and light is usually about a foot from the light head. This also makes it hard to pop the light off before running inside somewhere.

You get what you pay for...

...in support

Reputable lighting manufacturers have a brand to uphold, and I think that most of them do in fact care about their customers. I've met these people, and they're all passionate about biking. If you call them, a real person helps you with your problem. Good luck contacting somebody who was involved in the manufacturing of any of these generic lights. A handful of online sellers have earned a reputation for good service by immediately refunding or replacing failed lights... which is nice, until you realize that a product with hundreds of reviews saying "mine failed but they replaced it, they're so nice 5 stars!" still means hundreds of people's products failed!

...and in features

If you're on a tight budget, maybe "price" is your only feature requirement. But seriously, name brand bike lights offer many features which you won't find on cheap generic lights. Things like carefully designed optics, USB fast charging, well designed mounts, specifically designed daytime and nighttime flash patterns, side visibility, and more.

So, what are your options instead?

First of all, just to be clear, there are cheap Chinese lights which are safe to use. The problem is, these are widely counterfeited, so it's best to buy from a reputable dealer in your own country. Single-18650 lights are usually safer than multi-cell lights. Buying quality batteries is always a must. I have some recommendations on my batteries FAQ page.

I also maintain a frequently updated list of recommended bike headlights. Product recommendations are a bit outside the scope of Stack Exchange, so keep an eye on the website for recent suggestions, or come chat about it.


Upper pulley too close to chain Today i put my bike on my tacx home trainer.

I heard a lot of ticking on my chain, so after viewing my setup i recognized that my upper pulley is too close to my chain when it's on the smallest cog on the front and the smallest cog on the back.

I know this is setup is not most ideal (cross chaining), but i'm concerning and never seen before that my chain is going aginst the upper pulley.

Does anyone has some tips?

This sort of rub occurring in small/small, or the smallest cog of a 1x, is a symptom of the chain being too long, either because it was installed without being sized properly, or because it was a compromise made to cheat the maximum capacity of a rear derailleur, or because a cassette was swapped in that required less chain wrap and it effectively became too long, or because the bicycle has horizontal dropouts and the wheel has been moved forward from the position where the derailleur was able to tension the properly.

If your trainer has a cassette installed with a smaller smallest cog than what your chain was sized for, that would cause this. (A lot of mechanics size road chains based on preventing droop in small-small because this actually gives maximum cassette swappability for wheel changes.)

Because the bike has horizontal dropouts, it could also be happening in whole or part if the chain was sized for a wheel orientation that was further back, whereas in the picture you have it slammed.


Bike unstable (difficult to ride without hands on bars) after changing fork after collision After a low speed collision with the front of a car in which a cars bumper met the side of my fork (I was in a track stand-esque stance) my fork was bent slightly so I replaced it with a (inexpensive but good enough) fork from amazon that very closely resembled the dimensions of my original fork. The length from the bottom of the head stock to the wheel may be slightly longer on the new one.

Since replacing it, my bike has become difficult to ride without handle bars. I know that the forks geometry basically determines this, but I think the change is slight enough it wouldn't have made it unstable.

Could there be another reason for causing the instability or is it likely that the new fork is different enough geometry to cause this issue.
Things I've thought of so far:

Front wheel is untrue (checked and it's pretty good).
Front wheel is out if dish (didn't think about this until now so I'm not sure but it's hard for me to check since I don't have a truing stand).
Rear wheel out of true or out of dish (possible because I had to replace some spokes).

My bike is a 1980s Raleigh Capri (which is a steel frame) with some minor mods and generally well kept.

Bicycle dynamics

A bicycle may only be ridden because of the peculiar steering geometry. The centre of the contact patch of the tyre is behind the point where the steering axis intersects with the ground. The distance between these points is called trail. In order to visualise it you may have a look at this figure from the bicycle dynamics article on Wikipedia:

The trail is determined by a number of constraints: head angle, wheel diameter, fork rake, fork length.

In general: If trail increases, the bike becomes more stable on straights, if trail decreases the bike becomes less stable on straights.

How will your new fork change your bike's geometry?

A longer fork with the same rake will slightly slacken the head angle, as the bike is tilted a little. This increases trail.

However, it will also reduce trail as the ratio of rake/length becomes smaller. this is not correct

If the fork has more rake, it will very directly reduce trail.

Headset

A lose or misaligned headset will cause an unstable ride. You may test your headset as follows, if you have a rigid fork, i.e. no shock absorbers.

Stand beside your bike hold the bars, and pull the forward brake levers. Your brakes should lock the forward wheel. Then rock the bike fore and aft. Do you feel any give, any instability? Push down on the handlebars and force the bike fore and aft. Turn the wheel sideways and repeat.

Anecdote: I had an unstable bikes for years. I found only out when stripping it for parts that I confused the top and bottom ball cages of the headset bearings. The lower one led to a slightly too tight fit, the upper one was slightly too large. I never could really tighten that headset properly.

The original poster mentioned in the comments that their problem was caused by a similar mistake: "[I] realized that i had my bearings upside down."

Warped frame, damaged head tube, cracked frame

If a collision was strong enough to render your fork unusable it might have damaged the bike's frame. Some points you might want to check:

are there any cracks at the head tube? Did paint flake off recently?
Are head tube and seat tube parallel. Are head, seat, top, and bottom tube in one plane?
do you hear any creaking noises when cycling?

Bad tracking

Bad dish of your rear wheel and a warped frame may cause bad tracking. That is, when going straight the rear wheel does not follow the track of the front wheel exactly. When cycling the symptom is usually not so much instability, but more a tendency of the bike to steer to one side. You might still ride hands-off, but have to nudge the bike by shifting your centre of mass to one side.

You may easily check gross tracking problems by pushing your bike through a muddy puddle. If the tracks are straight, parallel, but do not coincide you have a tracking problem. If they are not straight, or not parallel, you have to push more straight (not easy at all, bikes are not meant to go straight!).


Is it safe to ride while taking mucinex (guaifenesin)? I've been getting over a chest cold, most of the worst symptoms are gone (like the sinus headache and tiredness).  However, I tend to have a bit of congestion that hangs around for a couple weeks after the other symptoms clear up.

I found that mucinex (guaifenesin) seems to help me with this since it thins the mucous in the lungs.  Is it safe to take this to be more comfortable on longer rides?  Is there anything I should be careful of?

Plain old Mucinex (without the "-D" suffix) is guaifenesin, one of the most innocuous drugs in existence.  Unless you have a peculiar (and rare) reaction to it, it should be about as safe as one can hope for.  In fact, I'd recommend it if you ride in dry or dusty conditions.

Mucinex-D, on the other hand, contains a decongestant that can cause drowsiness and other such symptoms in a substantial minority of patients.  (And I believe it can also be picked up in pro sports drug tests.)  You should take that while riding only after you've established that you don't react to it (and you're not in pro competition).

Also, of course, if you find yourself getting congested on rides that's a likely sign that you need to drink more water.


How tell if spokes too tight without tensionometer Is there a way to tell if a spoke or spokes are too tight, if you don't have access to a tensionometer?

I had to tighten several, and obviously I don't want them too tight, otherwise you risk broken spokes and damaged nipples/rims/maybe hubs.

Roger Musson's book "Professional Guide to Wheel Building" simply states that: "The best place to start when judging the correct tension is to examine a similar wheel you know to be good and reliable and compare the spoke tension to the one being built."

Musson does not use the sound of the spokes to determine their tension, only to find differences in tension between them.

Roger Musson's website does also have a good discussion about tensionmeters and their necessity when building wheels. http://www.wheelpro.co.uk/support/tensiometers/


Does height of bicycle affect the energy we put to ride? I used a road-bike (gearless) and its height was even not reaching to my waist and I was becoming very tired even after 10 min. of cycling (in city). I remember I have read somewhere that angle of legs position affect the amount of effort.

Does height matter? If yes than how to get the best bike (in terms of height)

Short answer: Height does matter (in fact, there are multiple "heights" which you can find out about in the long answer's links), but there are a ton of other factors (e.g. top tube length which is probably more important). The bike's geometry is what determines how well it works for you.

Long answer: What you need is a bike fit (which can be done at most bike shops). Proper bike fitting makes your power delivery good and avoids potential injuries / pain. The handlebars, brake hoods, stem length, saddle height, saddle width, possibly cranks (though unlikely unless you're on the extreme side of heights),etc.  will be adjusted based on your proportions (primarily your inseam as well as your reach) provided the bike can be fit to you. This is highly dependent as well on your riding style (racers don't ride the same way people going on cross country tours do, typically) and feel. Height and inseam are not sufficient (hence why they publish a ton of measurements per bike). I personally prefer a larger size than most people with my height (though I have longer arms + inseam than most people of my height)... See the links below for more details. The most common mistake people make is putting the seat too low (which correspondingly screws up everything else), but you really should start with a bike fit (or if this isn't possible due to financial constraints or something, surveying videos on youtube or something (but I will not link any, since this should be done with a LBS, and test rides)). As the KOPS link below shows, these systems aren't used as an exact science, so the experience of the fitter helps a lot in getting a good fit (the numbers plugged into formulas aren't everything), and it may take a few tries to get something that really works for you.

A good look on the problems with fit and why its left to the pros at your LBS is http://sheldonbrown.com/frame-sizing.html

As for what you read, it may have been KOPS: http://sheldonbrown.com/kops.html

There are multiple theories as to how you should setup your bike for "best" cycling. Once you get a fit, you'll end up tweaking it to better suit yourself and changing riding styles.

Getting tired also depends on how fit you are, and how efficient you are in using your gears - if you start in top gear on a racing bike, chances are you're going to get tired really quickly if you're not pretty fit. It sounds like you have a single speed, which means you have to compromise on one gear for the whole range of riding you do (unless you fit something like a Surly Dingle), so you may need to pick a different gearing combo, though typically these are set with a decent gearing which isn't too hard to start and easy to cruise in (like a 42t/17t on the Surly Crosscheck SS). If you have a fixie, your legs are always moving, so in this case, you may want a flip flop hub which allows you to flip the wheel and let you freewheel a bit when you're tired. Having multiple speeds may help with tired-ness depending on the terrain (hills make you want multiple speeds).

Getting a bike fit reduces the bike setup part of riding and makes your physical fitness the next problem (and possibly gearing). You may find that the particular bike you have cannot be tweaked to work with your riding needs! (For example, a lot of racing bikes don't work as tourers/commuters).


Indoor trainer suitible for sprinting Are there any types of indoor trainers that are suitable for training sprints insofar as they allow the rider to tilt the bike to get leverage as one would when sprinting on the road?

Check out the videos on the Kurt Kinetic Rock and Roll you can definitely stand and tilt the bike side to side.  Whether it would handle Andre Greipel in a full out sprint I couldn't say. It's probably one of the better options to look into.


Will panaracer 27.5x3.5 tires on Velocity Blunt 35 rims fit on a Medium Surly Karate Monkey Frame? Will panaracer Fat B Nimble 27.5x3.5 tires on Velocity Blunt 35 rims fit on a Medium Surly Karate Monkey Frame?

I doubt there will be any clearance issue on the front fork since it can hold a 29x3 surly knard with plenty of space.  However, I'm not sure about the rear triangle.

Yes.

http://surlybikes.com/gallery/karate_monkey/karate_monkey_b
It took me a while to confirm that these were indeed the panaracer fat b nimbles due to the low resolution of the image. However, it's definitely a panaracer, and there are only so many models that size. Like BEVR1337 said, I may have some issues if using a front derailleur, it looks like this should clear the frame fine. Rims appear to be velocity duallys which are a bit wider than the blunts, so if it is a good fit with these rims, the narrower blunt 35s should be totally fine.


Any wheel on any fork / frame? I have been braking for a bit too long with worn off brake pads on not so new rims so I basically killed them.

I currently have the stock wheels of an FX Trek 7.2 bike.

I will most probably change them. The thing is, that I would like to use the opportunity to install thinner tires. The current rims would support a range of 28-37mm wide tires.

The wheels I am looking at support 19-28mm wide tire range.

Will any of those new wheels fit on my bike without any further replacing? for instance because of the width of the fork?

How about brakes? I will obviously need to tweak them, but will it require more than just a set-up?

When buying new wheels, make sure the spacing matches up. Road wheels typicall use 130mm rear and 100mm front spacing where as most mountain bikes use 135mm rear and 100mm front. Hybrids vary, but it looks like this one has Shimano RM30 hubs which are 135mm spacing like a mountain bike.  However, if you find a 130mm spaced wheel you like, you can add spacers to make it fit the 135mm spacing of your bike if need be.

I think it's worth a shot trying out a 700x28c tire on this bike without changing the wheels, which would be much cheaper than switching the wheelset.

FYI, I got my spec information for the wheels from here: http://www.firefoxbikes.com/hybrid_Trek_73FX.html


Is a 7 speed chainring compatible with an 8, 9 or 10 speed cassette and chain? Currently I have a 7 speed cassette (13-23) running with a spacer on a new Tiagra hub. After I changed my chain, the wear has made two of the gears unusable.

I am considering changing the cassette to increase the number of gears. The simple option would be 8 speed (12-23). The other alternative looking at the chainrings would be a complete change to 9 (11-23) or 10 (11-25) speed and drop a few teeth at the front.

Will my current chainring be incompatible with a new cassette and chain? In other words, can I use a 9 or 10 speed chain with a chainring designed for a 7 speed cassette and chain? Is there a significant difference in durability between the setups?

I mainly use by bike for commuting and light road touring.

7 speed systems use slightly wider chains, and the teeth on the chainring are slightly wider too. You might run into an issue with a ten speed chain not fitting over the teeth, or at least not fitting well.


What benefits does a tapered head tube afford? I've just read a review of Tom Zirbel's Jamis Xenith SL on Bike Radar and flicking through the pictures there is one of the head tube with the following caption:

  Tom Zirbel's (Jamis Sutter Home) Jamis Xenith SL features a tapered 1-1/8 to 1-1/2in head tube - especially useful in a frame of this size

What benefits does a tapered head tube afford?

Lighter and stronger are the real gains. Also there is coolness factor. In a rare move I wish to cite Richard Cunningham from Road Bike Action for points 1 + 2:

Look, who has the longest unbroken history of carbon fiber frame making in pro road racing, uses the tapered fork steerer design to eliminate the narrow waist at the junction of the fork crown and steerer. This allows their all-carbon HSC6 fork to be laid up as one unit and in a manner that keeps the unidirectional carbon filaments that support the structure flowing from the fork legs, through the crown and up the steerer tube in a smooth, unwrinkled matrix. The more uniformly that the fibers are aligned where the crown flows into the steerer tube, the stronger the fork will be in its most highly stressed area.
Look’s engineers also developed a tapered lower bearing interface that eliminates the stress concentration that a conventional notched-type crown race would cause. The bottom line for tapered road steerers is that, done correctly, it streamlines the manufacturing process and makes for a better one-piece carbon fiber fork.


What is an 'Open Tubular' tire? I've seen several manufacturers, like challenge, offering what they call an 'Open Tubular' tire. How is this different from a standard clincher tire?

An "open tubular" is basically a tubular tire with clincher beads instead of being sewn. They use the same materials as the sewups, so in theory should offer some of the same advantages as tubular tires.

However, most of the pro's of a tubular (lighter weight, less rolling resistance, tire will stay on when flat) are voided because they've turned a tubular into a clincher. Plus, there are many modern clincher tires that have just as little or even less rolling resistance than a tubular (in some specific cases).


fixing front thru-axle wheel play Recently got a Poseidon Redwood gravel bike and after about 100 miles or so I noticed some front wheel play when pushing the wheel from side to side with my hand. Took the wheel out to see if the cones were lose or something but I could not figure out how to even get the end caps of.
The caps themselves have some play as shown in this video but just the same amount on both sides so I'm not sure if that's how it's supposed to be. I don't see anywhere where I could fit an allen key or wrench/spanner to take them off and I didn't wanna force them. The hubs have Quanta branding on them but I couldn't find any guide online for them either.
Any help would be greatly appreciated!

Most thru-axle front hubs have endcaps that pull straight off and are held in place with o-rings to gently create some friction.
You can use the thru-axle to gently rock them back and forth to work them off if they're sticking. On yours, if you have the kind that pull off, poking something through those holes and pulling that way should also work.
Some hubs have endcaps where one or both thread onto the main hub axle. Your symptom combined with the holes on the endcap in the video suggest yours could be like this. Try poking a tool, i.e. a 3mm allen or small screwdriver shaft, through the holes on each side and screw them towards each other and see if anything happens. If it is a hub with threaded endcaps, snug them down tight and you should be good. If not then take them off, make sure the bearings have no play and are pressed into their bores without issue, grease the contact surfaces of the endcaps and make sure they're all the way in, then put your axle on tight with greased threads and you should be fine.


Fit a throttle to a pedal assist.bike? Can I fit a throttle to a pedal assist Viking Gravity ebike?
If yes what is needed other than a throttle?
Thanks

It's going to depend on several things:

The controller
The type of pedal-assist detection
How good you are with electronics
Whether you can get a full kit for that model

If you can't get a suitable kit, you either need to be good at electronics (design and assembly), or pay someone who is.
I've sketched out a design in the past (on paper - I don't have them any more).  Here it is, with some other options.

One plausible and not too invasive idea involves faking the input to the pedal sensor with a throttle that gives pulses at a suitable rate.  This is what a former colleague was going to do after discussions, but analysing and generating electronic signals is the sort of thing we both do for a living.
Replacing all the controls and motor drive circuit may be an option, but how could you be sure the new bits would fit and be compatible with the motor and battery? Is the charging controller integrated into the same module?
The existing control circuit may have an unused throttle input (throttles are popular where they're allowed so it's not unlikely.  It may be very easy to interface or very tricky, depending on how much is present.


Is it OK to leave my bicycle unlubricated for a day after a hose-down? I just cleaned my bike with low pressure water but I don't have any lubricant. I left it to dry in my basement with the window left open.

Is there any chance my bike will malfunction or rust before tomorrow when I buy some lubricant?

No, of course not. Having your bike wet and unlibricated for one day won't damage it in any way. Washing it and letting it unlubricated for long period of time will cause you some issues. But one day is not a problem...


Is it possible to predict when roads will have less traffic? I'm planning a two day trip down the UK country roads. I'd like to time and plan my route so that I'll have a pleasant ride. Is it possible to tell which days of the week would see the least traffic? I'll be cycling from dawn till late afternoon on both days.

Generally speaking, Saturdays and Sundays are quieter than weekdays.

The Department of Transport collects various statistics on road use. This table (TRA0307) shows average traffic by time and day of the week.

There's also this table (TRA0306) which shows average traffic by day for different road types and different vehicles.

Finally, there are statistics for average annual traffic on every major road in the UK. There's an interactive map here.


How to reassemble a completely disassembled brake caliper? I have mechanical disk brakes in my XC bike and in the process of replacing the brake pads, I completely opened the insides of the brake caliper. There were three ball bearings and a spring attached to the brake lever. Now I have no idea how to put them in position, I tried assembling once but there is no any braking action to the wheels. I think I assembled it wrong. Can anybody help me with this issue?

EDIT 1: Here is the picture of the disassembled caliper. I am not sure of the brand because it is completely erased.

Here's a version of you picture with labels on the parts I'm probably not using the correct names but these will work for this purpose.

I'm assuming you know where each part generally fits but are having trouble getting the caliper to function correctly when assembled.

The caliper basically works by rotating the plunger. The ball bearings fit into the detents in the main body and plunger (marked by red circles). When the plunger rotates the balls ride up out of the detents on little ramps forcing the plunger to move through the body and press the pad against the rotor.

I think you probably went wrong in getting the ball bearings in the right place. When you put the balls in they should sit in the detents in the body, and the plunger should sit on the balls so that the balls are in the plunger detents. You should apply some grease to the moving parts and this will help stick the balls in place during reassembly. Be careful to keep grease away from where it could get on the pad though.

The spring serves to rotate the lever and retract the pads when there is no pull from the brake cable. There is a little spur of wire at each end of the spring that fits into a hole in the lever and main body (marked with red squares). Make sure the spurs are engaged in the holes. It's not clear which way around the spring goes from the picture but it should clear to you when you put it in place.

I'm not sure what 'part X' is. Perhaps a seal? Hopefully you remember how that fits.


Why don't brakes come with 'Safety Levers' any more? It used to be very common to see bikes with dual pull brake levers (if that's even the right name) as shown below. However now it seems almost impossible to find brakes like this.  Even finding a picture to post was hard.  It seems like it would be quite useful to be able to brake from various hand positions.  There was an answer I read a while back (can't find it now) that stated that there was a reason they got rid of those, but no explanation as to why. So any technical reason, or is it just for looks?

I believe there are multiple reasons that "extension"/"dual-pull"/"safety"/"suicide" levers aren't seen anymore:

They're really a solution for a poorly fit bike, where the rider can't reach the regular brake levers. Fix that and you don't need an extra lever on the flat of the handlebars. This was especially a problem for smaller riders. Bike sizing and fit have improved a lot since then.
Since they effectively pre-pull your brake a little, they reduce how much travel you can get out of the primary brake lever which can reduce the effectiveness of that primary brake lever. (I guess some designs don't have this problem, but most did)
Using them puts your hands in a location that doesn't give you much leverage for controlling the bike.
It's an extra piece that can break (and leave you unable to brake). Especially, if the main brake lever is knocked out of alignment, the extension lever will hit the handlebar.
Modern brake levers ("aero"?) have a different pivot setup that works better over all, but especially works better with hands on the hoods than old levers did. Extension levers simply won't work because of the way a modern lever pivots. If you look at a modern brake lever, when you pull the lever the top of the lever doesn't go down, it goes forward, and extension levers rely on pushing down on the top of the lever. Sin As you can see from these blurry pictures of a vaguely modern brake lever, the pivot is somewhat low and in front and the top of the lever rotates straight forward.
Somebody invented "interrupter" or "cyclocross" levers which go mid-cable instead, allowing you to get the same end result (a second brake lever) without any of the problems of extension levers.
Some regulation changes and historical market realities that ʍǝɥʇɐɯ discusses in his answer.


Alternatives to buying a repair stand? I'd like to buy a repair stand, but I can never seem to convince myself to drop the $100 minimum it seems I'd need to spend.  Has anybody had any success building a stand themselves, or is it worth it to just buy one?

As a number of other posts have pointed out, your best option is to get yourself a proper repair stand. They are not that expensive, and you will find that you and your friends all get good use out of it. But, if you are determined to do it on the cheap, here are a couple of techniques that worked for me before getting a workstand:

Turning the bike upside down - this is really simple and requires no additional purchase. You may want to look at putting some form of drop sheet down underneath the bike both to protect the saddle and handlebars, and to catch drips. This works well for pretty much any work on the wheels or transmission.
A bike storage rack or car rack - obviously these are already designed to hold a bike, and you may already have one to hand.
Suspending the bike with rope - If you have some overhead attachment points, this can work, however it is not going to provide an immovable mount for the bike - you will still need to hold the bike against the force of your tools when fastening and unfastening things. A trick to be aware of is to use two suspension points overhead and two on the bike (head tube and seat tube) otherwise the bike will spin in the air.


brakes are wearing out very fast, why? My rear brakes are wearing out very fast.  I am on my third set since Christmas (2 months). I have no idea why this is.  It is a rim brake.

Assuming disc brakes, some reasons for short pad life could be:

Riding conditions - If you're riding in gritty mud, pad life will be shorter than dry conditions.  The mud can form a grinding paste which wears the pads quicker.

Damaged rotors - If your rotors are scored or damaged, this can accelerate pad wear.  If you've worn a pad down to the backing plate this can damage the rotor and lead to shorter pad life.

Not bedding the pads in sufficiently - New pads straight out the packet need bedded in before use.  This typically involves putting them through a few braking cycles to bring them up to a high temperature.  Pads which have not been bedded in, will wear quicker when subjected to wet muddy conditions.

Pad material - Brake pads come in different materials which can have different pad lives depending on usage.  E.g. sintered pads should last longer in muddy conditions than resin pads.  However, some brake discs are not designed for sintered pads.


Can I install an upright handlebar (curved towards me) on a touring bike? I bike around the city on a daily basis, usually for short distances (5 km tops, typically less than that). I currently have a cheap, battered down touring bike that is nevertheless doing the job surprisingly well, and I think it can work for quite some time more with the proper maintenance.

However, I'd like a more upright riding position. I used to have a dutch-style bike and I found it much more comfortable than my current one, even though it was way too small for me. When riding my touring bike I very often find myself sitting as upright as I can while still holding the handlebar with the tips of my fingers, and I think, "only if this handlebar would curve towards me..."

So I think I have about three options right now:

Spend around $600 in a dutch-style bike (new or second hand). That's going to get me a very heavy bike with 3 gears, maybe 5. My experience with this (the 3 gears part) is terrible.
Spend way more than that. I don't want to do this, not because I can't afford it, but because I park my bike in the street all the time, and bike theft is a thing here, not a rampant problem, but it happens. The more the bike is worth, the more likely it is to get stolen.
Spend a fraction of that on a dutch-style handlebar and install it on my bike. I'd need longer cables too, and maybe a wider seat in case the increased weight on it makes it uncomfortable, but it's still cheaper and I end up with a better bike than in option 1.

So I guess the question is, is this a good idea? Or is there some danger that I'm not aware of? I feel there must be something wrong with it, otherwise I would have seen plenty of bikes like this already.

Edit
This is the model I have now (only the seat is different)

is this a good idea? Or is there some danger that I'm not aware of?

You can safely install different shapes of handlebars on all bikes (when done properly).  If you want to keep your current stem, make sure you buy a handlebar with the exact same diameter as the old one (this is exact to a fraction of mm).  Or if you want/need to replace the stem make sure you buy a stem that is compatible with your fork.

Edit after photo has been added:

I am quite confident you can safely replace these handlebars with "Dutch"-style bike handlebars.  The most complicated would be to make sure you can safely use the brake levers.  Adjust the angle by rotating the lever before tightening it down.  Most brake levers allow to adjust the reach of the lever, in case you have trouble comfortably reaching for them.  If you don't feel comfortable making these adjustments yourself, it would be best to have a bike shop do it for you.

Good luck!

You didn't provide much information on what handlebar you have now.  Nor what brake levers and shifters are fitted on them.  And this is where the costs might go up quite a bit.  For example, if you currently have drop handle bars, your levers are not going to (safely) fit on the handlebar you want to use.  So then you need to replace the brake levers and shifters, keeping then in mind that you need to buy levers and shifters that are compatible with your current brakes and derailleurs.


How to cut a counterbore for chainring bolts with simple tools There are some 5-bolt 110mm BCD double cranks out there (FSA Tempo Adventure) that put the large ring on the inside of the spider tabs. I want to figure out a way to use whatever 110mm rings I want with them so I'm not tied to a specific, hard to get, iffy quality replacement FSA ring. What's the simplest way to cut a serviceable chainring bolt counterbore into a ring with an existing hole and counterbore on the other side?

What I did in the end was this:

The new chainring was a black Dimension with a pretty generously thick tab section. I actually went with an unramped one, but running it flipped wouldn't work because of its offset. Running it without a counterbore for the nut caused the chain to get stuck on the nuts when in the inner ring.
I used a countersink drill bit in a hand drill to cut away at the holes on the non-factory-counterbored side until the hole on the top surface was enlarged to the diameter needed to clear the nuts.
For grins, I tried stopping there and mounting the ring that way to see if force from the nut/bolt would be enough to squish down the material sufficiently to give the chain clearance. It didn't work.
To create the counterbore, I decided to get risky, and used my Dremel freehand with the baby endmill looking bit that came with it, which I think is a Dremel 196 bit. I carefully cut from the inside of each hole out to the major diameter, then went in a circle from there. The countersink bit took away half of the material that was in the way of me making this circle, whereas the bit going off course into where I didn't want to cut would require a lot more force, as would driving the bit deeper, so I was able to use tactile feedback to stay pretty much on course.
After getting it most of the way there, I cleaned it all up with alcohol, and colored the cut areas with a Sharpie. Having it all black again let me observe any irregularities and touch up those spots to better keep the surface for the nuts to bear against flat. I also tested that the nuts were sitting neatly just below the surface of the ring.
I mounted it all up and the counterbores worked perfectly. Because the crank in question is strange, I had to play with spacers under the small ring to work out issues with chain rub on the new large ring in more gear combos than I liked.


Name/style/model for this brake spring? I bought a cheap assemble-yourself bike and the front brake spring came bent. I'm having trouble googling a replacement since its a no-name brand. Any advice on how I might go about buying a replacement?

(And obligatory safety disclosure: yes, I carefully inspected and tested the rest of the brake system to make sure this was the only defective part.)

It's called the spring or return spring for a side pull or side pull caliper brake. A replacement is usually found by searching for the maker and model of the specific brake.
Finding a replacement will be tough. The complete brake mechanism is very inexpensive making the individual parts so inexpensive they aren't worth keeping in inventory.
Criggie is right, using two pliers or a vice and one plier twist it back into the correct shape and use it.
Springs are supposed to be made of spring steel known for it's ability to be bent and return to it's original shape. In spite of it's ability to bounce back it can be bent in such a way as to hold a new shape.
In your case you need a very small adjustment that should not impact the spring characteristics of the metal.


I want to switch my front and back brakes I want to switch my brakes to have the front brake be on the right and the rear on the left?  How do I detach the cables and reattach to the opposite lever?

Assuming you have cable operated brakes, the basic answer is you have to detach the cables at the brake calipers, and pull the cables out of the housings through the levers. The levers hold the cable via a boss swaged onto the end of the cable, so that’s the only way to get the cables out. You can then switch which levers the the front and housing rear housings run to and re-thread the cables.
Cable strands often get unraveled by the pinch bolts that hold the cables on the calipers which makes the cables impossible to thread back through the housings, so new cables from the outset are a good idea.
You may encounter difficulties with switching the housings between levers depending on the existing housing routing.
You also need to know how to re-adjust the brake calipers when you re-attach the cables, but good quality guides are easily found on the web.
If you have hydraulic operated brakes things are more complicated. Hoses can be swapped but you have to deal with avoiding spilling hydraulic fluid and bleeding both brakes afterwards.


Recovering COnfidence after bike fall It's been 3 months since my bike accident, I've had at least 10 critical accidents. Sometimes I don't even know how I am alive. Recently, I had a bike crash when going down the hill which broke of 2 of my 2 front adult tooth. When I fell, my face scraped against the rough terrain, i was unconscious after accident, I had to undergo major surgery on the bottom half my face, My lips had a hole straight through it (enough for a thick pen to be put).

My face has recovered but every time I walk down the hill (everyday), I think of everything that happened that day. The worst thing is the amount of blood from my face on the floor hitting my memory again and again . It shakes me out.

My parents are telling me not to ride again ( I'm 19) but whats the fun in that. I'm trying to build the confidence but its sooo hard.  Also bike became "un- ridable"

Any tips? What bike next? had mountain bikes before, thinking of road bike but doesnt seem like a great idea.

I am not a doctor, but its sound like you might be suffering Post Traumatic Stress, and should seek professional help to rule it out or get treatment.

You should be concerned about the 10 critical accidents (I read critical that as hospital/doctors visits and time off school/work, not a mere "off" ). You are likely riding beyond you limits, and need to learn to ride safer - (rein in the testosterone). Accidents happen, but 10 before the age of 20 is to high.  Its a numbers game, and with that many, one day you will not ride another day.

Have you ever had, and are still getting coaching? This would be my first step. You need to learn why you are pranging and getting hurt, and stop the "getting hurt" bit. Prangs are a part of pushing things when MTBing, getting hurt regularly is not.

In the end, if you cannot rein it in, switching codes (I presume you are down-hilling/freestyling with those stats) to XC, Cyclocross or Road may be wise.

And do listen to you parents. They don't want you to stop riding, they want you to stop getting hurt. They dread having to arrange a funeral or  remodel the house to suit a paraplegic.


Repair Marin Hawk Hill (cracked frame) or get new bike? I have a 2017 or 2018 Marin Hawk Hill. It has a cracked frame (see photo). My local bike shop contacted Marin, who said they have a frame that can be used. It would also require a shock replacement. The total, including labor, would be $750. I am wondering if it is worth it to do this or if I should instead buy a new bike. I don't want to spend a ton of money, so the replacement frame is appealing, but I also don't want to end up wasting money.

A new similar bike would cost ~1500 €/$/GBP, right?
For half the price, you get a new frame, a new shock, all your old&used parts (in which conditions are they)?
No brainer:
If you think your parts are worth at least 750$ and you can sell them for more than 750$, sell them and then buy a complete new bike.
If you think your parts are worth less than 750$, accept their offer (or find a better deal on a compatible set frame+fork)


Chain slipping on smallest cogs (bigger chainring, new chain) I recently switched my SRAM 1x12 Eagle SX drivetrain from a 30 to 34 direct mount Chainring. I also bought a new chain to accompany with it. Chain length was measured as the sram service manual advices. Put the chain around the largest rings and have 4 links overlapping.
The cassette has around 700km.The previous chain had around 0.5% procent wear.
When going into the highest gear and one cog beneath it by chain slips when applying pressure. The other gears work fine.
I degreased the new chain upon arrival since it was very sticky and applied dry lube after washing off the degreaser and drying using a towel.
I read online and some advice the cassette need to be replaced but after 700km to me that would be really strange. Could the chain slippen have something to do with the derailleur height? Which might be different since my chainring has chained or is this not correct?
I assume a larger chainring does not have impact on the left/right adjustments of the derailleur?
Another option I was thinking about was wiping as much dry lube of the chain applying wet lube.

You can play around with chain-wrap and cable adjustment all you want but this problem is 99.999% of the time caused by wear on the cog's teeth. Ask your LBS if they can sell you only the cogs you need. It may seem like the cassette isn't old enough to justify being worn out, but that's a 10 tooth cog you're talking about, a tiny piece of thin metal responsible for handling all those watts we put down! ;) Plus, considering you made the switch to a larger chainring, I get the impression that you were doing a considerable amount of riding in your highest gear, accelerating the wear it experienced.


Wheel set consideration Background: I'm overhauling/refurbishing my second road bike that I use mainly for training. It needs new wheels.

I found a couple of nice used 2011 wheelsets that were spares for a women's bike team and saw very little use. The rear wheels are 28 spokes; I have a choice for the front wheels. Either 20 spoke or 24 spoke. What should I think about to make the choice? (clinchers)

I weigh 160lbs if that matters.

If the bike is used mostly for training, you'll probably want to give high priority to reliability. In general, more spokes is better than fewer both because they're stronger and also because they're easier to true; 2-cross (or 3-cross) spoke patterns will be stronger than radial or "mixed" spoke patterns (for example, radial on one side and 1x on the other); rims with eyelets will be stronger than rims without; clincher rims will give you more choice about heavy-duty or puncture-resistant tires and tubes than tubular rims; aluminium rims will be more cost-effective than carbon; standard round spokes will be easier to find replacements for (should you need them) than bladed spokes.


Should I buy average tires with puncture resistant tire liners or just puncture resistant tires? The reason I am asking this is I am a pretty big rider who carries cargo sometimes. Let us say close to three hundred pounds all told. The streets where I live are terrible with many pot holes. There are also a lot of construction sites that will be there for the next few years. I got nine
flats in one month/150 kilometers. They are not pinch flats. All are at
the exact center of the outside of the tube. They are not always in the same spot either. Only once have I seen any debris embedded in the tire and I didn't think it was responsible for the flat. They are the stock tires from when I bought the bike a 2017 Norco Yorkville. I would just bite the bullet and buy great tires like schwalbes but could really use the funds elsewhere on the bike. I forgot to mention. The tires are inflated to 75 P.S.I. close to the 80 max.

Exact center of the outside of the tube (and no debris) indicates a pinch flat.  Why do you assert not a pinch flat?

My experience with tire liners is they abrade the tube.  I would wear out a tube a year riding about 500 miles.

Puncture resistance tires work better for me.

Why you are not seeing debris in the tire is a mystery to me.

You might also try tubes with sealant for small punctures.


Differences between Izoard XP 2013 and Izoard XP 2014? I wanted to buy a Wilier Triestina Izoard XP.
The dealer told me that the Izoard XP 2013 with Shimano 105 cost 3021$ and I would have sold discounted to 2060$. The same price of the Izoard XP 2014 with 105. I asked why the new model would cost the same amount of discounted old model and he told me that the fork of the 2013 better than the 2014. I don't understand from Izoard XP 2014 spec if it is better then Izoard XP 2013 see english 'Bike Specification' in this italian site. Is a matter of fork?

Annual improvements in bikes tend to small and incremental. They have been doing this for over 100 years, unless someone comes out with something revolutionary, its hard to see how they can make a big difference. If it is revolutionary, it won't be the same model name (and it wont be 105).

For me, a grand in the wallet makes the 2013 a better bike. In a year, the 2014 will be a grand cheaper and in two years the same price on the second hand market as the 2013. If I wanted to spend $3000, I would buy the 2013 model of a $4500 bike.

Only you can decide if small incremental improvements are worth the money to you.


What can be done to fix a hub that has come apart? I noticed recently that my rear tyre was rubbing on the frame when I was pedalling hard; the wheel had a bit of horizontal play in it, so I thought the cones might need tightening. Anyway, I left it another couple of days, until at some point the wheel suddenly developed a lot more play in it than before. I looked down and saw this:

TL;DR: My rear hub currently looks like this. You can see the bearings inside; none have come out yet and I've stopped riding the bike. Will a hub service sort this out? Or is it likely that I will need a new hub/wheel?

That looks fixable to me.

What probably happened is the locknut was loose, and continued riding caused both cone and locknut to unscrew. It's a good job you've stopped riding that bike - riding on that hub now would cause significant damage.

When a hub has a bit of play, the balls are free to move across parts of the cup and cone that aren't designed to support load. Those areas may not have been heat treated and/or polished. That can cause metal wear, resulting in particles grinding between the balls and the 'proper' bearing surfaces. Result: pitted cups and cones.

When a hub has a lot of play (as in your case now), the problem is exacerbated further - the balls may slip out of place completely and bind the hub, causing irreparable damage.

That hub is dirty and the grease is foul. Pull the axle, clean the hub inside and out, and clean the axle, cones, and locknuts. Use a good de-greaser, or failing that, ethyl alcohol, lighter fluid, or equivalent. Wipe it all clean with a lint-free cloth and inspect. If the cups have any scratches you can feel with your little fingernail, I'd ditch the wheel. If the cones have any pitting, I'd get a new pair. Whatever the state of the innards, get a new set of bearing balls.

Sheldon will show you how to re-pack and adjust the hub. It's not difficult, just a bit greasy and fiddly. Wear latex gloves if you like.

It doesn't look like a particularly special hub, so I wouldn't pay a professional to do it; balls and grease are cheap. Do your best and ride it 'til it fails; then just get a new wheel (it's rarely, if ever, worth the cost of lacing a new hub to an old rim).


Do I really need a magic link or can I just replace the pin on my chain? To install a new chain I need a chain tool to shorten it to the proper length.  Why not just use that same tool to replace the pin and not deal with a magic link?  Seems to me the pin would be stronger than a breakable link.  Am I missing something?

You can do that (*) - you just need to make sure you don't push the pin out all the way before reinstalling it (else it becomes quite hard to put the pin back in). However, a quick link is easier to install and remove (**) the chain (also, carrying a few of them around make for easy emergency repairs), since you only have to use the chain tool to shorten the chain and not risk damage to the plates when re-attaching or not aligning the pin correctly when re-attaching (this is the most common cause of failure for a chain, especially on higher speed chains). Thus, re-installing the pin is more likely to weaken the chain vs a quick link (which doesn't have this problem).

In any case, the quick link isn't usually the place of failure, so theres not really a reason not to use it unless your chain doesn't come with one.

(*) Well, check the documentation that comes with the chain. Normally, if there is a quick link, the manufacturer will tell you to use it, which the end of the paragraph will tell you why.

(**) On 10/11 speed systems, they are normally one time use links. On lower speeds, you can open and close the chain a bunch of times.

(***) As the comments point out, Shimano chains ship with a special pin to use (as do some Campy chains). You have to use this pin in this case (see this link for details/intricacies).


Can I buy an aluminum seatpost with a chromoly frame I'm starting to plan to build a bike and am looking at parts. I found a frame I like (Poloandbike CMNDR frameset) which is chromoly, but am now trying to find a seatpost to go on it. I believe the seatpost on the frame is 31.6 mm. I found a seatpost I like (Kalloy Laprade SP243) which is made of Al6061T6. My question is, is it alright to have an aluminum seatpost on a chromoly frame? I know some alloys will need grease or different conditions, so I wasn't sure if this would be an alright things to do. Any help would be greatly appreciated.

There isn't a problem with putting an aluminum seatpost in a steel frame. It's a pretty common thing to do.

Make sure to grease the seatpost before putting it in, lest it get stuck. If it does get stuck, you could try ammonia or drano (sodium hydroxide) or chilling the thing (e.g. with a CO2 cartridge to unstick it). See this page for other stuck seatpost suggestions.

Also, make sure you have the right diameter seatpost. This can be done by checking the documentation for the frame, or using a seatpost measuring tool (which most bike shops should have), or a pair of vernier calipers.


What physically makes chainrings have a specific speed compatibility? Chainrings are sold as having a specific compatibility for only certain speed setups, some overlapping across many. What physically makes this the case?

From what I understand, 5/6/7/8/9 speed chains all have the same internal width, 3/32", and the only difference is the external width of the chain. Does this also extend through 10/11 speeds as well, or do they have smaller internal widths which would necessitate skinnier chain rings as well? Or is it the case that the external width just keeps shrinking?

IF the difference is only the external width, then it would seem the only compatibility issues would not be in the chainrings themselves, but the spacing in between each one. If it was too small/too wide a chain, the chain would hit the next chainring, and if it was significantly too large the chain may fall in between rings.

However, it would seem that you could use the same rings with a wider chain (9 speed rings with a 5/6/7/8 speed chain) if you put appropriate spacers between the rings, such as these. The opposite may be possible if you're willing to grid / mill the appropriate amount off the mounting pad.

What this would also imply is that with the right width spacers (and bolts that can accomodate them) you could always go down speeds with a given set of chainrings.

If that is not the case (say 11 speeds have a different internal width), then they might be too wide for the chain an you'd have to remove material near the teeth to make them fit inside the chain or conversely that you'd be wearing on less of the chain than you should so your chain wouldn't last as long.

Furthermore, some rings are marketed as 5/6/7/8 speed only, some 9 speed only, and some 5/6/7/8/9 compatible. Is this some sort of blending of the two specifications (the spacing being some compromise between true 8/9 speeds) or just that they're made for one but tested to work on the other (or just a marketing trick)?

The internal width is obviously one important feature.  But for indexed shifting the ring has a pattern embossed on the side facing the smaller ring that catches the pins of the chain when shifting.  The combo of the embossing depth/pattern and the ring-to-ring spacing affects what width chain (and brand chain) will work best with the ring.

I've no idea what combos can be expected to work with what, though.  I lost track when they went to 8 speeds, and now it's a total free-for-all.


Is there a recommended way to center your handlebars? Is there a best practice for centering your handlebars in the stem? Besides eyeballing it, I actually tried measuring distances but found that depending on where I measured from and to I got different results. For example, the screw in the cap to the top of the hoods would show they are off by one amount but measuring to the end of the bars would show a different amount. Is there a most true set of landmarks to use? Does it depend on the quality of the bars? Does it even matter?

It sounds as though you have drop bars, and one of your measurements is to the brake hoods. Since those are independently attached to the handlebars, that measurement only tells you that something is off, not what it is (you have two measurements and three unknowns - the bar position in the stem, the left brake level position on the bar and the right brake lever position on the bar).

I assume there are no markings on the bar, and no bulge where the bar thickens to 25mm from 22mm, otherwise you wouldn't be asking?

I suggest loosening the stem off and making a mark on the centre point of the bars, measuring from a point that has a sharp edge. If the bars are new the end of the drops is good, but on old bars one or both end is often bent a little. Even 5mm makes a noticeable difference here. If the bars have been taped the tape will also affect the measurement, which is why the bar end points are good.

But regardless, the next best way to measure is from the inside of the forward-swept part of the bars. Get a ruler that's longer than the width of the bars and place it on top of the bars, at 90° to the bike's long axis (across the handlebars). Line it up parallel to the bars, so that it's just in front of the cross part. and the same distance forward on both sides. I find that lining up the forward edge of the bars and the back edge of the ruler works well. Then measure off the forward edge of the ruler, since that's on the straight parts of the bars.

Here's a quick top view:

Ideally your bars will not curve this much, or you'll use a wider ruler :)

This lets you measure the exact width of the bars. Halve that, and measure in that far from one side. That's the centre :) Now make a mark there, or better still, mark the ruler and centre the bars in the stem with it in place. A couple of rubber bands can be used to hold the ruler in place while you do this - put them on the rule, put the ruler on the bars, pull a band under the bars and over the end of the rule. Repeat for other side. Now wiggle the bars in to position. Test ride, and make sure it feels right.

Mark with a permanent marker both sides of the stem so you can line it up easily next time.

Also, now if you repeat your measurement to the brake hoods you can twist one or both on the bars to get them symmetrical. If you prefer them that way.

This also works for most other curly bars.


9 Speed Road STI + MTB Derailleur Apologies if this is is obvious or has been answered before.

I'm looking at setting up a touring bike, using road STI levers (Shimano or equivalent, looking at Tiagra 3x9 or possibly the Microshift 3x9) with a MTB derailleur (probably just Deore) and 9 speed cassette, in order to get the gearing right for loaded riding.

Will there be any compatibility issues?

For Shimano gear If you are going all 9-speed, you're fine using most STI shifters with 9-speed mountain derailleurs.

New 10 spd Dyna-Sys rear derailleurs won't work with 10 spd STI shifters if you're going Shimano.  However, I've heard people have had success using a 9-speed Shimano Deore M592 Shadow Rear Derailleur with 10 speed STI shifters.

See thread on MTBR for a bit more info on someone's successful setup with a Shimano 10 speed road/mountain setup http://www.bikeforums.net/archive/index.php/t-673861.html

I don't think there are any issues if you're going for a SRAM road shifter / mountain derailleur combination if you're going 10 speed and using the XX mountain group which has the same pull ratio as the road groups. It appears that 9 speed mountain gear and some of the other 10 speed mountain group sets, have a slightly different pull ratio and don't play well with road shifters.


Hole in road bike tire This is 700x25 continental Ultra Sport II

I noticed there are two holes in both tires, and wonder if this is a manufacturing fault, or simply a wear indicator?

Yes, those are wear indicators.

The change is noted by retailers:

  Note: Continental has added wear indicators to all Continental
  Gatorskin tires. These small divots in the tread surface are
  intentional and are not a sign of a factory defect. Once the rubber
  wears to the point where the divots are no longer discernible, you'll
  know it's time to replace.