What's the point in a freewheel/cassette with incrementally sized rings? Pictured is a freewheel with 15, 16, 17, 18, 19, and 20 tooth sprockets. What I don't understand is why such small increments are worthwhile. Surely the point of having gears is the variance that they provide? Please enlighten me.

The point is efficiency.

Cyclists actually have quite a narrow optimal power band. Most of us can bang away at a cadence of 50 rpm, up to about 90 rpm. Some of us pedal faster - 90 to 120 rpm. At those lower cadences (50) it feels like we're producing lots of power and at the high cadences it feels like we're just breezing along. But that is confusing torque with power. The optimal power band is where we produce most power most efficiently.

How narrow is that power band? Take me as an example: 50+ years of road cycling, leg muscles well trained to buzz along at 100 to 120 rpm. My optimal power band is 105 to 115 rpm - on a flat ride I can do that for hours. If my cadence is dropping on a rise or into a headwind and I'm starting to grind, I know I'm down around 100. On a hill, after I run out of gears, if I can maintain a cadence of 90 or above I'm happy. But it's not as efficient.

So there are three factors to consider: the rider, the terrain, and the wind.

Terrain. On a flat road, close spacing gives us scope to choose the optimum gear. On a hilly road, we might want wider spacing at the bottom of the range to help with climbing. For MTB, AFAIK such a cluster would be unsuitable, but I'd welcome input from an MTB rider.

Wind. On a circuit, wind is like hills. Except that we always seem to have a headwind. Whatever. In wind a cluster with wider spacing helps.

The Rider. You. Where is your power band, and how wide is it? With training it will change. You'll hear many riders say that they "top out", meaning they couldn't pedal any faster (look at the tables below and see what that means). More factors come into it now: training and pedals. Pedaling fast takes practice, not just to pedal, but to do it smoothly so you don't bounce uncomfortably. And you have to be "clipped in" - no flat pedals.

But I digress. A general purpose 10-speed road cluster for a strong rider might be

  11, 12, 13, 14, 15, 17, 19, 21, 23, 27

The difference between each gear at the top end (11 to 15 teeth) is between 6% and 9%. At the bottom end, the difference is about 10%, except for the "granny gear". Taking our narrow power band into consideration, and assuming we have 39x53 front chain rings, that means we'll be able to find a comfortable gear at a wide range of speeds.

On the 39T chain ring, at 90 rpm (as an example; it's the ratios that matter, not the exact cadence):

  19 kph on the 23T sprocket
  21 kph on the 21T
  23 kph on the 19T
  25.8 kph on the 17T
  27.5 kph on the 16T
  29.3 kph on the 15T
  31.4 kph on the 14T
  34 kph on the 13T
  37 kph on the 12T
  40 kph on the 11T

And still on the 39T chain ring, at 110 rpm:

  23 kph on the 23T sprocket
  25.5 kph on the 21T
  28 kph on the 19T
  31.6 kph on the 17T
  33.5 kph on the 16T
  35.8 kph on the 15T
  38.3 kph on the 14T
  41.3 kph on the 13T
  45 kph on the 12T
  49 kph on the 11T

So, if you were riding at 30 kph, you could choose from the 15T cog, the 16T or the 17T. One of them will (in my case the 16T) be closest to your optimum cadence.

Switching up to the 53T chain ring, at 90 rpm:

  26 kph on the 23T sprocket
  28 kph on the 21T
  31 kph on the 19T
  35 kph on the 17T
  37 kph on the 16T
  40 kph on the 15T
  43 kph on the 14T
  46 kph on the 13T
  50 kph on the 12T
  54 kph on the 11T

And still on the 53T chain ring, at 110 rpm:

  32 kph on the 23T sprocket
  35 kph on the 21T
  38 kph on the 19T
  43 kph on the 17T
  46 kph on the 16T
  49 kph on the 15T
  52 kph on the 14T
  56 kph on the 13T
  61 kph on the 12T
  66 kph on the 11T

So now, considering that we have both chain rings available, you can see that at 30 kph you have 2 more possible gears. So depending on the terrain ahead, you would choose the big or small ring and the appropriate back cog.

For even stronger riders, the bottom gears are only 21 and 23, or maybe as low as 25.

Hope that helps!


bike pump hose split My bike pump hose keeps splitting in two halves. First time it split near the base of the pump (which i fixed by discarding the smaller piece and inserting the longer one to the base of the of pump) and now it has split right in the middle. I searched the internet but could find nothing like this reported before. I am perplexed, what could be the likely reason? I have been keeping the pump on the floor inside a closet for about four years and the two splitting incidents took place in the last month. Nothing else in the closet or the house have damaged. It looks like a very sharp clean cut:

Thanks!

If its at a point where the hose bends naturally, then it could be weakened by flexing.

What about temperature?  Could it be the hose is simply perishing with age?  Heat accelerates aging, so if its been hot or in sunlight for a while it will age quicker.

Look very closely at the split.  Is it smooth or slightly rough?  If its smooth, consider a sharp object may be involved.   Or is the hose getting caught under a weight, or in a door or track?

Do you have cats or kids ?  One has claws and the other can have scissors.

Answer: Time for a new length of pressure hose with the right Internal Diameter.  Outer diameter is less important, and matters only at the ends..  inside  Get a couple metres and fit it.  You may need some small hose clamps too.    Do try and repair it, a good pump should last a hundred years.


How did these pimple/bubble/bump shapes form on my tube? I've been riding on the same rear inner-tube for several months without issue. I topped up the rear tube last week, went on ~10mi ride (including a rest in the middle), and had no problems.

I was about to ride again today, but when I looked at my rear wheel I noticed the tube was completely flat.

While removing and inspecting the tube I found two obvious bumps/bulges/protuberances/knobs on the inner-tube.

These bumps are near a spoke. They are on the inner wall of the tube.

I found the source of the leak. One of two bumps has a sizeable hole/cut. It's not a slow leak. If I try to pump it does not hold any air.

I remember now that last week, after that ride, I had heard an odd noise from my kitchen (where I store my bike) and couldn't find the source when I went to check on it. I thought, "that's odd", but didn't think twice.

In hindsight that noise must have been my rear inner tube very suddenly deflating. It wasn't a bang, but a sound vaguely similar to a bag of rice falling on its side and the grains coming out quickly then slowly then stopping. Sort of like a deflation now that I remember it!

The issue isn't glass or debris, and the tire does not have a bubble and otherwise is not deformed or damaged when I inspect it.

A similar question and answer makes me think that perhaps I overinflated it when I thought I was doing things like normal, but I've never experienced this particular behavior before and was curious. Also, that user did not notice these obvious deformities like I did, so I thought it could be a different scenario.

On feeling the rim tape, I do not notice the spoke protruding out at this spot, but I do notice an obvious dimple/depression in the rim tape at that spoke!

What may have caused these bubbles?
If poor rim tape may be at fault, must the rim tape be re-done?

Unfortunately I'd have to bring the bicycle to a shop mid COVID-19 lockdown for anything beyond changing the tube, as I'm only really equipped to swap out the tube with my skillset.

For context, the tire says 700x28c, the wheel says 700x18c/23c. That discrepancy between 28c and 23c always bothered me, but I have no idea if it matters. The bike has been like that since I bought it ~7 years ago and multiple mechanics at multiple shops have replaced my tubes and tires with similar ones and never mentioned it. The max PSI is 115 and I usually only inflate to ~100 PSI, if my pump can be trusted.

The culprit is the rim tape. The glue that holds it in place has lost its grip, and when the tube is inflated, the tape is pushed away and lets the tube to extend into spoke hole. Eventually the edge of the spoke hole cuts the tube with the results that you described.

In my experience, this is what cloth rim tapes do. They can be replaced and there are tricks to gluing that may or may not help, but in my opinion the easiest solution is to buy a pair of plastic rim strips and replace the tape with them.


How to mount Galaxy S3 on a mountain bike I want to mount my Galaxy S III on my mountain bike. I already use a case that suites me well, so I don't want to go for another case. What I'm looking for is a mounting system which will mount my phone with it's case on to my bike securely and by that I mean really secure, because I ride pretty rough terrain regularly. I really like Rokform, but it requires to switch to their case plus it's very expensive (around $100 for the whole solution), I'm planning to spend not more than $30 on this. So to put it short I'm looking for a universal solution, that can securely house and mount Galaxy S III in it's case on a mountain bike.

You're going to have to go with something purpose made for that specific model of phone to get a secure mount on the bike. I'm not aware of any universal phone mount options that are worth anything, however you can browse Wally World if you feel like wagering $20 one yourself. There are few different brands, but the Bracketron universal mount has sealed/waterproof zippers whereas the Arkon does not. I can tell you from personal experience that the Arkon universal car mount I have has had to be Frankensteined back into working condition about 4 different times over the last several years, so I don't have a lot of faith in their products.


Silent kick stand? How to? Is there any way to make a kick stand silent during riding on uneven, stone roads and paths? I am actually refering to the "cube kick stand" for the "cube acid, kick stand ready, 2017" mtbike.

Presumably this is the stand you have: https://www.cube.eu/en/equipment/components/kickstands/product/cube-kickstand-cubestand-cmpt-black/

You need to determine what part of the kickstand is loose and moving when you go over bumps. You can inspect the stand, but also try dropping the bike onto it's tires from 6"/10cm off the ground. That's enough to reveal things that rattle. Bear in mind that something else may be rattling, it's hard to hear where noises come from when riding.

Perhaps the mechanism attaching the stand to the bike has come loose. Is the extendable leg rattling? If so maybe it can be solved by pushing the leg all the way in when you'll be riding bumpy roads.


What to look for when buying cyclo-cross or road bike under 600eu/650usd? I really want a fast bicycle, that I could use in winter, summer, rain & snow to commute to work. After some research I found out that there is a cool option of cyclo-cross bikes that are build for speed, but can have better tires, mud protection... (winter/rain).

I would use bike mainly to commute to work, usually would ride bicycle on city roads (no off-road or mountain driving). Danish weather is usually moody (rain, little ice here and there) therefore I want something that could have more durable and stable tires.

So again, i came across cyclo-cross bikes and now I was wondering if it is possible to buy a good one under 600eur. Talked with colleagues that have great bikes and they started talking about gears, breaks, handles... and in the end of conversation they summed up that the bike will cost at-least 1500eur.

The thing is, it would be my first 'good' bike and I am not going to go pro or whatever (just commute in different weather). So I decided that I can only spent up 600eur and then I wonder what is the most important things to look for in the bike.

I appreciate any suggestions, tips, help or direction where I should look for bikes to buy/order. Thanks! :)

Cyclocross is a type of bike race, which means that most true cyclocross bikes will be expensive, as they are built to win races. You won't find much for that price range if you buy new. But racers are always looking to go faster and get new gear, so consider getting a used bike. You should be able to find a very good used bike for that price.

Also consider looking at touring bikes. They are built quite similar to cyclocross bikes. Except that they are built at little stronger because they are built to carry more baggage. They also have mounting holes for racks which will come in useful for commuting. Many cyclocross bikes don't have the ability to mount racks because racks aren't used for racing.


Bicycle's inner-tube got puncture right next to the valve, How to patch it there? There is a very small cut 1-2 millimeter or less long in the inner-tube, right next to where it's the bottom of the Schrader valve. The cut is only 1-2 millimeters far away from the valve's bottom.

The hole has a shape of a cut, parallel to the valve's edge, and it's very close, so it's very obvious likely that the valve was part of the reason (the other reason being the valve moved a lot probably because the inner-tube was not inflated.) Air escapes out of the hole so it needs to be repaired.

I don't know if I can put a normal patch, because if the patch's edges detach even only a millimeter from the inner-tube, the hole will no longer will be covered and air will again escape. Any idea?
I give my 2 ideas:

Take a bike patch and cut a round hole in the middle, and then patch the inner tube with it, as if it were a ring, hugging the valve by all sides.
Get some super glue or cement that covers the hole somehow.

That's a very hard area to patch properly (if its even possible), and I'd recommend putting a new tube in instead of trying to patch it. .

I'd also check that the rim tape on the rim is intact and in good condition, cause otherwise if its busted, you're going to get another cut. Also, as pointed out by ChrisH in the comments, rough edges on the rim hole can also cause this problem (you can use a small file to smooth them out, if that is the case).


can i replace my rims 622x19 hybrid for a 622x17? i have a bike my rear wheel was stolen here in DC. the original was a 622x19. i have one which is 622x17 my question. is that ok ans safety to use it on ky bike?
thank you.

You should be perfectly fine, the 622 is the ERD [effective rim diameter] in mm. The other number is the inner width of the rim. What this effects is the range of tire the rim will hold. So your rear wheel will be slightly thinner, which is kinda strange but not that big of a deal. You can probably fit a 1.95" (700x50) tire on there without any issues but i would not try and go any wider than that. If your using 700x35 or something similar you should be just fine.

Make sure to check the axle spacing though, you can measure the axle of the replacement you have and then measure the rear dropouts. If its a steel frame and they do not match you should be able to space the frame a little with no issues. If its an aluminum frame make sure the wheel is the correct axle length. You can't space aluminum.

So yes! You can use that size rim with no issues assuming it is the same axle spacing. As always if your change to a larger tire size make sure your frame has clearance but it sounds like what your doing is pretty straight forward.


What is the narrowest tire you would use for commuting? Speed isn't so much of a factor, obviously, but the lower the rolling resistance the less sweaty I am when I get there. Then there's flats to consider. Basically the tire has to never get them because I can't be late. So what size would you ride?

For my commuting needs, I use Continental Gatorskins 700x28c.  I also use Mr Tuffy liners to help protect against punctures.  Using this combination, I haven't had a flat in 2 years.  Before going to this combination, I would get about 1 flat a month.  I travel about 14 km a day, 5 days a week, April to the end of November.

I recommend that you leave enough time in your commute to change a flat if need be.  For me, this is only about 10 minutes. Your time may vary.  My job is such that it's not a big deal if I'm a few minutes late.  If your job requires you to be right on time, you may have to sacrifice being early on the off chance you do get a flat.

Also, ensure that your tires do have enough air in them. If you use skinny tires, a lot of flats come from snakebite flats, caused by not enough air pressure.


Making your cycling gear smell less post ride Is there anything I can do to make my cycling gear smell less after I have arrived at work?

My problem is my baselayer tends to stink. Then I stink when I put it on at the end of the day to get home.

Can just feel the comments from others. Geez what do you expect! Am I suppose to bring my entire wardrobe to work.

I have a similar problem. My cycling shorts and jersey get quite nasty sitting in a locker at work after a sweaty morning commute.

I rinse shorts, jersey (and helmet) in warm water, then hang them where they can dry during the day. (There is no risk of theft where I work.) This helps substantially, although it's only partially effective during the height of summer where I live which is hot and humid.

(For those wondering where and how I rinse my shorts and jersey - the answer is in the locker-room shower, and yes, I have sometimes just gotten in with my gear still on.)

I also keep a number of jerseys in rotation so each gets a proper wash after each hot commuting day.


Any drawbacks in using long-travel forks with huge sag instead of regular XC fork? There is a trick which some cyclists use. Instead of the regular fork, let's say 100mm, they put a fork with bigger travel (140-160mm). Then they pump pretty low pressure so the sag is huge and the new fork has about 100mm of actual travel. This gives extreme plush.
Technically, the result is a 100mm fork with huge negative air chamber. A little heavier than the original one.
Is it actually notably softer?
Will such a fork resist strong bumps as good as normal 100mm?
I'm not advertising this and never tried by myself, but I received such recommendations. What I really like to hear is your personal experience.

Lots of drawback for this. I think too many to list, and some of them are subjective.
First, if you want to improve the performance of the front end, you don't just change one variable (ie fork length). All bikes are specifically designed on purpose and if something doesn't work well, there are more fundemental problems than that.
My first suggestion if you want to improve the bike, would be to see a qualified person that has lots of experience on that specific type of riding. Not any mechanic or random person.
Different travel bikes have their specific amount of travel for a reason, the harder hitting, the bigger travel (to a limit), the less extreme, the less travel. If you change the amount of travel of a bike that was suited to 100mm, you will take away a lot of it's specific properties, ie it's bump vs pedalling efficiency.
2 scenarios:

You add 40mm travel and set the fork how it's designed to be riden (ie correct sag etc). What you have done is drastically changed the geometry of the bike. Whether this is good or not, is subjective. The fact is the bike will desend with more stability but will pedal badly and corner much worst. Not to mention the extra stress on the frame which may break it.

You add 40mm travel and set the fork so the geometry of the bike is the same (ie very under pressure). What you have done is put a poggo stick on your front end. Yes, you won't feel small bumps, but you won't be able to stop bouncing.

The take away message should be, either improve your current bike by properly fine tuning your fork or upgrade to a better, more suitable, fork which does what it's supposed to do.
On the other hand, you might actually need more travel, as your type or stype of riding dictates that, then you should get a different bike more suited for your riding. You don't take an XC bike to ride enduro or visa versa.
I learnt a lot about this watching Vorsprung Suspension on YouTube. Some of it gets pretty technical, but it's fantastic to learn.


Hearing a strong sound when hitting a curb I bought a  hardtail MTB about a month ago (a complete beginner) and the way I'm dealing with curbs is:

I'm going at a decent speed
I slightly lift my front wheel
I shift my weight off the back wheel (it's 27.5" and i have it on near maximum pressure
) and it hit the curb (and I hear a strong sound - sort of metal hitting concrete)

I had my friend to check if anything was touching the ground, he said nothing but the wheel.

Is this the right way to do it? Do I need to put more pressure to the wheels?
Thanks for your time, I really appreciate it.

The technique is correct, ideally you are lifting the front followed by the back wheel so they clear the curb (the back wheel brushing the curb lightly is OK). This is known as a J-Hop or American Bunny hop.  The technique does take practice as the timing has to be accurate, looks of videos online that teach how to do it in sequences. The English Bunny hop is an alternate way - simple lift both wheels off the ground at the same time and land at the same time -  with enough speed you clear the curb. Both techniques are valid and have their place.

Often the noise comes from the the chain hitting the chain stay. If you are are on small cogs, its more likely to happen (more slack in the chain and close to the chain stay), if you have a clutch derailleur (and the clutch is engaged), it is less likely to happen.


Panniers stuck in tire spokes! I ride my bike as primary mode of transportation everyday. Recently, I decided to start using panniers for groceries, to spare my shoulders. I hooked them on to the rack on my bike, and rode to Trader Joe's just fine. Packed them up with my purchases, then rode home. I ALMOST made it all the way home, but about two blocks from my house I went up a ramp and the back corner of the bag on the left-hand side caught in my spokes! It sounded like my bike was exploding. I got off and started walking, but had to stop every few seconds to pull the pannier back out of the spokes. What is most likely to have caused this? It seemed like I had it installed correctly, and felt like the grocery weight was equally distributed in both bags. It also seemed like going up the ramp that led to the bike lane triggered it.

How can I prevent this from happening again, since I live in a neighborhood with lots of hills and don't want to deal with this every time there's an incline in the road?

I once had this happen before by combining inexpensive saddle bags combined with a inexpensive rack.  The bags were not stiff enough for things like groceries and the rack provided no support to keep the saddle bags from twisting.   With the heavy weight the bags simply twist into the spokes while riding.

I now use higher quality expedition style panniers and racks (picture below). These have lots of side support to keep panniers/saddlebags from twisting. The panniers themselves also have stiff inserts to prevent twisting. I have put close to 120 lbs on the bike (front and back) after big grocery run with no such problems.

Also a photo of the rack and bag setup will help diagnose the problem.


Anyone know what brand this emblem is from? I am curious to know if this is a custom head badge or if it is a stock emblem. searched the images on head badge sites but no luck. I even uploaded image to search by image engines and no correct results. so wondering if someone knows this emblem decal.

It's Rapid, I seem to recall, but I don't know if it's the supermarket brand of that name.

The blurry pic shows 'RA' as the first two letters, but both Raleigh in UK and Raleigh USA have consistently used the same tall heron logo as the head badge on their products.

The model name of this bike as given on the frame would help pin the company name down.


Which rear wheel axle does my “Citizen Gotham 7” folding bike use? Which rear wheel axle does my “Citizen Gotham 7” folding bike use?

Citizens' web site photos show a standard quick release on the Citizen 7. The three speed internally geared models use a bolt on axle.


Raleigh Alpine 4.2 Shimano front wheel and rear brakes assembly Hi I recently purchased a Raleigh Alpine 4.2 Shimano.

I am having a bit of difficulty with assembling the bike. Would anyone be able to assist with fitting the front wheel. I have included pictures of the right side of the front wheel the left side and the fork of the bike.

With regard to the brakes, it seems that the brake cable fits into a small hole on the silver lever on the left. I don't want to damage anything hence I don't want to apply force. The red and silver cable seems to large to fit into this hole. Does anyone know which part of the cable should be placed in this hole?

Thanks for any assistance let me know if any further info is required.

The internet is replete with resources for bike assembly and maintenance. Park Tool Company has a particularly comprehensive set of articles and YouTube videos.

Wheel axle obviously fits into the slots in the dropouts in the fork, and then the nuts are tightened on the axle. I imagine you need to know if the washers go inside or outside the dropout slots.

Check out this article, look for a section titled "Solid Axle Systems", You can see that the tab washers go outside and fit into a hole in the dropout.


Switching brakes from mechanical to hydraulics. Disk rotor question Can I use the disk rotor from the current mechanical brake when I switch to hydraulic?

Yes this will be fine.

The only caveat I can think of is rotor thickness, if you look closely on a rotor or read the manual, you should be able to find the minimum thickness.

This is different for different manufacturers but shouldn't affect a hydraulic disc brake, they automatically adjust for pad and rotor wear and will happily clamp a pair of new pads together with no disc in between.

See this question about pad material. I wouldn't worry about that either.


Rear wheel moving from side to side Rear wheel is moving from side to side anyone have any ideas what might be the problem thanks

Check out the link below. This question has been answered already and they do a pretty good job of explaining the possible issues/solutions.

Rear bike wheel wobbling


How to measure calories burned? How can I accurately measure the calories burned while using my bicycle?  My bike computer tells me how many calories I have burned.  But it has no cadence meter. The only measurements it has are my weight, distance, instantenous speed, and time (and all information it can derive from that).  Using the GPS on my phone, and the software from Sports Tracker on the same route, I got wildly different results.  The information on sports tracker yielded about 1.5 times more calories burned then on my bike computer.  Now, the GPS has a little more information, like altitude, but the ride was mostly flat. To add to that, there was an elevation drop over the entire route, so I don't know why it would say I burned more calories.  Do these devices use standard formulas, or do they just make stuff up?

Is it even possible to accurately measure the calories burned?  It seems that even if I had a cadence meter, there would still be a lot of variables.  Wind speed would make a big difference.  If you pedal with the wind at your back on a fixed gear, going 30 km/h, you are going to use a lot less energy pedaling the same bike at the same speed if you are going into the wind.  Note that in both these cases your cadence would be the same, but your muscles would be working much harder in the case where you were working against the wind.   Same could be said for things like hills, although this could be done with altitude, although I'm not sure how accurate you could get. Road conditions could also make a big difference, not to even get into the riding characteristics of the bike.

Yes, it's possible to measure calories burned. To do so accurately you need some sort of power measurement device.

More accurate and more portable are the mechanical systems that attach to your bike - PowerTap is one example. These measure torque and speed at some point and work out power from that, often with corrections for various factors (input vs output power being the most obvious).

Less accurate but possibly more useful to you for training are the systems that attempt to work out the  biological power input. They work by measuring the difference between inhaled and exhaled oxygen or carbon dioxide, and generally use terms like VO2 Max. The apparatus for this is not even vaguely portable, so from those numbers they derive a relationship between your heart rate and your moving average power output (the response is not instantaneous), and on from there to your total energy output.

The cheap systems you see advertised will either measure bicycle speed and from that attempt to guess your power output, or measure your heart rate and guess likewise. Obviously the "what sort of bike do you have" and "what sort of hreat rate response do you have" questions are at best vague approximations to the truth and will vary over time. But the measurements are dramatically cheaper to make so they're consequently more popular.

A few years ago a friend looked at various mechanical systems and decided that PowerTab was the only system that was usefully accurate for him. We did break a couple of the cheap systems while trying to improve their accuracy, but that was acceptable because as sold they were useless to us. The VO2 systems are the definitive training aid because they tell you more than just average power output, and the other outputs are actually more useful than power output. Mechanical systems are the easy, every day measurement that gives you your overall progress, or for us, lets you evaluate the vehicle performance as well (to some extent we don't care whether you are five seconds faster at the same power output because the vehicle is more efficent, it fits you better or you have got stronger, we just care that the combination is more efficient).


Brake cable housing doesn't attach to lever I got a new bike but the front brake doesn't work. I tried reading up about the brake system on line and learned quite a bit (they're cantilever brakes). But I am missing something elementary and simple.

(1) Should the brake cable housing (the outer housing that the thin brake cable runs through) be affixed to the brake lever?

(2) If so, how do I attach it? My bike has two brakes -- Shimano STI levers and Tektro safety levers on the front. The cable runs through both, but there is no tension in either, and the housing doesn't attach to the Tektro lever -- it kind of just slips out of where the adjuster is located.

I know this must be a really simple problem, which is why I'm frustrated not to find instructions for what I should try to resolve it.

Thanks for any advice or pointers!

OK. Thanks for the additional info.

Start by making sure that the brake cable is connected to your drop lever. Check this out: http://www.parktool.com/blog/repair-help/shift-levers-shifters. The cable itself has a metal tab crimped onto the end that connects it to the lever. (Find the relevant photo. The brake cable is the larger cable. If this doesn't look familiar, you can search for more specific instructions on brake cable replacement for your particular STI model).

If the cable is correctly seated in the lever, make sure the cable hasn't become unclamped at the cable yoke (the metal bit which connects to your straddle cable linking the two sides of your cantilever calipers). You should be able to gently pull down on that yoke and feel the pull of the lever when you depress it. You can read Sheldon Brown's instruction on canti adjustment here: http://sheldonbrown.com/canti-trad.html

Make sure before you make any adjustments that the housing is seated at all of the cable stops. Also make sure that you are relatively confident in your skills here. Your front brake provides MOST of your braking force. If in doubt, definitely bring it back to the shop you purchased it from.


How to tighten gates belt drive on Focus planet 8 the belt on my focus planet 8 is becoming a bit loose and I thought of tightening it.

The rear wheel setup on the focus is similar to the one in the video from bikefriday below:

What is different is that my bike does not have the adjuster holes to change the tension. There is the big long thread, but at the end there is no hole for an allan key nor is there a hole for a screwdriver to adjust?

Pictures below:

Does anybody know how to deal with this?

Below are the pictures from the side:
sideview1

I imagined that the process should be: open the 2 bolts from the outside, then tighten the inside "bolt" on the chainstay. however I don't see a way how to perform the last step, as it is not a bolt nor a screw that i have on the inside chainstay.

thanks

It's hard to tell from your pictures, one from the side would be nice.  I did a search and came up with the following picture.

If this is what your bike looks like, then you need to loosen the two bolts I've labeled on both sides (4 total) and slide the wheel back until the belt is tensioned correctly. Make sure the wheel is straight and even on both sides when tightening everything back up. From looking at your pictures, it also looks like you should tighten the bolt on the inside of the chainstay where you've circled in red to prevent the wheel from slipping.


Don't like upright position so which bike should I choose? Hi I used to cycle quite a lot and about 26 years ago bought a men's trek singletrack 970 which I loved. That eventually got stolen, and I haven't ridden for many years, but when I tried out some bikes at the beginning of the year they all felt like I was sitting upright which just felt wrong!

I think times have changed with bikes (and I'm older so maybe not so flexible but hopefully don't have to go to a ladies bike yet!) But I would still like to try that geometry before I give up! Any ideas of brands/models that might recreate that position?

It’s awesome that you’re getting back into riding again. MTB style bikes have gotten a lot more sit-uppy in the years since you last purchased a bike. Their geometry has gotten a lot more slack and the headsets a lot shorter and the wheels are bigger so you tend to sit “in” the bike rather than stretched over the top of the bike.

This might be an occasion where you should talk to your local bike store to see if an MTB is still what you want or whether a gravel bike which is a modified road bike with fat tyres but still has drop handlebars, might suit you better. It really depends on the terrain you want to ride on.

A good store might be able to recommend changes like a slightly longer headset to an off the rack bike to stretch you out a bit too. Also some brands tend to be longer in the frame than others.

Good luck with your search.


Wheel Building - Should key spoke be inside or outside flange? I’m working on my first wheel build and reading a lot of articles about spoke patterns. Some articles say the key spoke (drive-side, to the right of the valve) should be on the outside of the flange, but others say inside of the flange.

Is there a recommended/better flange side for the key spoke? And then what is the recommended flange side for the spoke on the other side of the valve?

In my current build my key spoke is on the outside of the flange. The parallel spoke on the other side of the valve is inside the left flange.

Update

Here’s my finished wheels showing the lacing pattern. I followed Shimano’s recommended pattern but would love to know if it looks in/correct to anyone. In both pics, the wheels are drive-side up, with the valve at the top-center (in the T of WTB). All spokes on drive-side go to holes on drive-side of rim, same for non-drive side.

For the pulling spokes, the knee should be at the outside of the hub flange (i.e. spoke heads inward).

If you look at the wear marks of a used hub (picture below ; pulling direction clockwise) you see that the pulling spokes leave a strong impression on the hub flange. Such marks are absent on the inside.
The knee of a spoke is the most vulnerable spot. With the pulling spokes running tangential on the outside of the hub the load on the knee is shifted to the line of contact of the spoke with the hub. Also the dish (see https://en.wikipedia.org/wiki/Bicycle_wheel#Dish) is larger when the pulling spokes run outside, which increases lateral stability.

In building a wheel and making final adjustments in spoke tension, you often have to add or reduce a small amout of tension on each spoke. It is difficult to avoid a torsional wind-up because the nipple doesn't rotate freely. There are many craft practises to reduce and release this wind-up, but often they leave some residual tension. If the pulling spokes are running inside the hub, the wind-up tension is mostly concentrated on the knee of the spoke. If the pulling spoke is outside the hub, the wind-up tension is more distributed between the nipple and the hub.

For disc-brake wheels, the spokes on the disc side running forward share most of the braking force. So they also should be mounted with the spoke heads inward.


Is it viable to use cottered cranks? I'm restoring a Bianchi Sprint (~1975).

It has a cottered crankset/bb. I was originally planning on replacing them, because we all know that cottered cranksets are junk, right? Well, they have a great Q-factor and the rings I want (52-42, because it's got DT shifters), so I'm looking at trying to make them work.

I know cottered cranks are gone now because square taper is a better, lower maintenance, more foolproof system. But that doesn't mean that cottered cranks can't work well, right?

Is it going to be an ongoing nightmare trying to keep these cranks working smoothly and silently? This bike would be used heavily (~100 miles/week).

Give them a try.

The main reasons they used to fail, if my boyhood memories are accurate, was incorrect installation.

When installed firmly they would last for years.

The important thing is proper support for the bike and pedal arm while installing the cotter pins. The pins must be hammered in firmly, without transmitting any of the hammer impact to the BB bearings. Destroying the bearings was common. After installing the pins firmly the nut on each should be tightened to hold them firm.

If you have a source of the correct cotter pins then trying will not cost much. If you find them to be too much trouble then you can always such to plan B: a square taper BB.

The Spirit crank and chain rings were integrated, so you'd need new rings of you replace the BB.


Bottle dynamo: the steel wheel quickly wearing down? 4 weeks ago I replaced the bottle dynamo on my bike (see this question).
Now, after 4 weeks of commuting for a total of something less than 600 km, the dynamo runner looks like this

It won't take longer to have the rest of the runner completely flattened, therefore I am considering moving to a better dynamo.
I can choose between:

low-end dynamo with steel runner (cost around 10 Euros)
high-end dynamo with plastic runner (cost around 40 Euros)

Aside from cost consideration, is it advisable to use a steel runner? Is there any risk that the steel runner can tear the side of my tyre?
P.S. Hub dynamo is out of question.

The roller of the dynamo should run on that ribbed track under the treads. And the axis of rotation of the rotor needs to point very precisely at the axle of the wheel. (I've always checked that with a piece of string!)

BTW: The roller doesn't look worn to me. It looks as if it had been machined that way, compare with a new one. And you may also find a rubber cap that fits over the steel roller although this will increase the diameter and make the dynamo turn at a lower RPM and dim the light in an unwanted way.


How to align rear v brakes i have a bike that has v brakes on the rear wheel. Everytime i try to align the brakes after i ride and use a few times the rear brakes, one of the pads is rubbing on the rim. Please help as i have spent a lot of hours on it without gain anything. Thanks.

One of the likely culprits is that you've put too much spring tension in on the arms. Start by loosening the spring tension on the arms, adjusting the brake and then increasing to just enough tension.

These links will be useful.


When does a Marathon Plus tire (not) need replacing? I have Marathon Plus tires:

5 years old
15000 km
bike stored indoors

I'm getting more punctures than I used to, but maybe that's caused by my riding now on worse road surfaces than I used to. The punctures tend to be slow leaks from sharp grit (crushed stone which surfaces an unpaved path) embedding in the rear wheel.

Total weight (me and the bike and stuff) is about 200 lb, and the tires are always properly inflated.

Is it plausible that the tires are less puncture-resistant than they used to be, i.e. is it worth replacing them now if I want to avoid punctures? How can I tell? Is the fact that they still have tread (aren't worn smooth) proof that they're not worn significantly?

Schwalbe's web site says,

  Against 'time bombs' such as shards, flints and glass, only a thick rubber belt like Smart Guard will work.

Is it possible that the inner belt isn't working as well as it used to?

The tires are still very rideable but is it likely that they're now significantly less reliable than when new?

It's not nearly as visibly worn as shown on Schwalbe's 'Tyre Wear' page, which shows tyres that are "worn out" and "need replacing urgently", and which says,

  The tires of the Marathon family usually last between 6000 and 12000 km. ... The Marathon Plus is outstanding with its extremely high mileage of often much more than 10000 km.

If this helps at all, I used a set of Marathon Plus tires on a cross-Canada tour last year (8200km), plus a bunch of commutting, totaling about 11,000km. I did not get any flats at any point, but by the end of that distance, the rear tire was pretty bald and I decided to stop using it.

Here's a picture of the tires around 10,000km, front tire on the left rear on the right. I consider the rear tire bald here since the part actually contacting the road has none of the factory tread remaining.

Three thoughts I'll share:

The Smart Guard is an extra layer of rubber between the road side and tube side of the tire, and depending on tire model it is one of a few non-black colors. I think the Marthon Plus is blue, and they do green on some tires, etc. Inspect your tire carefully in good lighting and see if you can see the colored middle layer anywhere, even a small patch. If so I would chuck the tire since that means you've broken through to the middle layer and the road side of the tire could start delaminating from there.
If your tire is bald but you can't see Smart Guard showing through, and you want to keep using it but are getting a lot of flats, check it for small embedded puncturing agents that may be stuck in the tire and puncturing your tubes repeatedly. E.g. on our tour, a couple of the other guys who were also using Marathon Pluses had a run of flats, i.e. one a day for several days. After careful inspection we found a couple of tiny wires, like human hair thickness and 2mm long, embedded in the tire that were almost invisible, but poking through to the inside and putting pinholes in the tubes. We eventually determined they were radial belt wires being picked up from the side of the highway from areas where transport trucks had had blowouts. You can get similar repeated slow punctures from tiny glass slivers.
If your tires look like mine (rear very worn and front quite new looking), resist the temptation to swap them between front and rear wheels. A worn tire is a greater candidate for blowouts and other major failures, which in turn are more likely to cause injury when they happen on the front wheel. If you don't want to replace both tires, then chuck the fully worn rear tire, move the partially worn front tire to the rear, and put a nice new tire on the front. More info on this here.

Hope that helps.


How do I know if my cone/cap/bearings need to be adjusted? I have a custom road bike with (mostly) Shimano parts.  I love to ride but I'm not so strong on the technical side.

I have quick-release wheels; I regularly (3-4 times a year) put the bike in a bag and travel by train to a cycling destination.

When I did so, upon re-assembling my bike, I noticed there was a lot of "play" in the rear wheel left-to-right.  It rolls smoothly, but there is an intermittent....feeling.... as the wheel rotates when I am riding it.

The feeling is a feeling of some friction, but not enough to actually retard the forward motion of the bike or anything, just enough to allow my feet to feel it in the pedals.  It appears to happen once a rotation, as if I am going fast enough, I can't feel it anymore, but when I am going slow, there's certainly a pace to it.

I've heard anecdotally from a friend I may need to adjust my cone & bearings, as they may have become too loose.  Does anyone have any advice on how to do this, or things I should watch out for?  I'm trying as much as is possible not to ride until I sort this, but since I commute by bike, it's urgent.

Pick the bike up so the problem wheel is off the ground.  Grasp the tire and push it back and forth (left/right relative to the frame).  If you can get any perceptible motion then the bearings are loose and need adjustment.

While the wheel is off the ground, spin it and watch the space between the rim and the brake block (assuming you don't have disk brakes).  The space should be nearly constant, varying no more than about 1/2 mm as the wheel rotates.  (Check this on both sides, since a dinged rim is also a possibility.) If it varies more than 1/2 mm or so the wheel is out of true and needs to be trued.

Both tasks -- adjusting bearings and truing the wheel -- are things that a competent basement mechanic can accomplish, but not particularly suited for a newbie, so in either case it needs to go to a bike shop.


How can I tell if a helmet will be comfortable before buying? Barring taking a helmet on a 50-mile ride before buying it:

Some kinds of chin straps, for example, won't stay tight, and some kinds of cages aren't comfortable no matter how I adjust them. What should I look for?

This isn't a product recommendation question (although that would be nice). I'm interested in knowing what features to look for.

Alternately, is there anything I can do to an existing helmet to make it more comfortable on longer rides?

(If it'll help, I ride for commuting, running errands, and touring; aero or ultra-light features are appreciated but aren't a priority, but ventilation is important.)

Put one on your head, adjust it to fit, and then try to slide it off your head in all directions. If you feel any pressure points or hot spots, you then need to determine if that will be alleviated by the little bits of foam included with most helmets, or if you need a different size or model of helmet.

As far as long-ride wear-ability is concerned, when you try on a helmet you need to be very aware of places the hard foam contacts your head. You also need to be aware of the weight of the helmet and ventilation when you start thinking about long rides. In most cases, for rides longer than about 2 hours, a more expensive (read: lighter and more ventilated) helmet will be more comfortable IF and only if it fits ok on your head.


Can i use a 10 speed hubbed wheel on my 7 speed/cassette bike? I ride a 2005 Claud Butler San Remo with a Sora 7 cassette on the back. My back wheel has broke and is not repairable and I have bought an Ambrosio WS23 Wheel (700mm) with Bianchi hubs which I believe had a 10 speed cassette on.

I have been told it needs to be a Campagnolo cassette but can't seem to find any 7 speed cassettes from Campagnolo? Could I put an eight on it? Would i need a spacer? I want to know what my best/cheepest/easiest option is or should I just forget about it and try and get a Shimano hubbed wheel?

Getting a 7-speed (or indeed any) Campy cassette wouldn't do you much good anyway since the rest of your drivetrain will be Shimano. As you've discovered the two don't mix. (Or rather, they are not supposed to mix and you can expect problems if you do try to mix them. Never say never, I guess!)

I reckon your cheapest option could be to visit your LBS and to see if it is possible to take the wheel you bought, and to swap the Campy freehub to a Shimano freehub. I have no idea how easy this would be or how much it would cost. Worst case the LBS may want to rebuild the wheel, although there could be an easier way, I don't know.

Next option, as you've identified, is to get a new wheel with a Shimano freehub - any chance you could exchange the wheel you just bought? Normally there's no cost difference between the two freehubs. But as long as you have a Shimano freehub you should just be able to slip your existing cassette back on (provided you have the right tool).

In terms of expense, I wouldn't recommend trying to fit the drivetrain to the wheel you just bought, that will mean several part replacements and costs will mount. You also need to be careful if you start thinking along the lines of upgrading your 7-speed cassette, certainly when you get to 10-speed, things like chains and derailleurs come into play, so you may need to replace more than you bargained for.


Are there any bus companies that take bikes and go between Washington DC and Philadelphia? Some googling turns up a chinatown bus company ("focus transit"), but I called and they no longer go to Philly.  Anyone else taking bikes in the luggage bay as of summer 2015?

It turns out that Focus Transit actually goes between DC and Philly still.  The guy on the other end of the phone didn't know what he was talking about when I called.  They take bikes.


Must a Bicyclist Riding on a Sidewalk Stop at a Stop Sign? Riding my bicycle legally on the sidewalk, I approach an intersection controlled by a stop sign. Let's say there are wheelchair ramps at the intersection, and there may or may not be painted pedestrian crosswalk lines. Must I make a full stop before crossing the side street?

My question pertains to California law but I realize that the answer may differ in other jurisdictions. Also, it may make a difference whether or not there are painted crosswalk lines, and whether the road is to my left or to my right.

The strategy, if legal, may be useful to bicyclists who may avoid having to make a full stop by riding on the sidewalk shortly before reaching the intersection.

Another situation is a 3 way intersection with 3 stop signs where I am not crossing a side street. If I am on the street, I know I must stop, but I am quite confident that I am not required to stop if I am on the sidewalk.

As a side issue, it does appear that it is legal for me to ride on the sidewalk in California with the road to my right and continue to ride between the crosswalk lines across an intersecting street. California law treats the crosswalk as an extension of the sidewalk, thus giving me the same rights that I have on the sidewalk.

According to the state's site about bicycles, there are only laws against riding on sidewalks for certain locales. Otherwise, similar to most states, you are governed as a pedestrian when riding on the sidewalk. That means if you dart in front of traffic unexpectedly, even in a crosswalk, you can still be at fault.

However, you should ALWAYS stop at an intersection, regardless of whether you are a pedestrian or a vehicle. It's polite and it's a heck of a lot safer than assuming the coast is clear. And don't be that guy who rides on sidewalks just to avoid traffic laws and stop signs, nobody likes that.


Shimano Ultegra 6800...what do I need? I'm gearing up for my first bike tour.  I have an old motobecane cross bike, I think it's a 2007.  I need more granny gears.  Right now I have a 9 speed 12-26.  I'm looking into the Shimano Ultegra 6800 stuff, and so far it seems affordable with great reviews.  My question is, I know I need the cassette, chain, derraileur & shifter.  Anything else?

Shimano 11 speed road cassettes are wider than previous models, so you most likely will need a wider freehub body. In some cases it can be bought separately, but given that you have 9 speed at the moment, I find it unlikely, so add an 11 speed Shimano road rear compatible hub to the purchase list.


Shimano LP25 Sealed Cartridge Bottom Bracket I recently attempted to rebuild a sealed cartridge Shimano LP25 bottom bracket. These are meant to be replaced when worn out, but I thought: if someone on YouTube can do it, I can too. The problem is that the top bearings no longer fit, as the first picture illustrates. I am completely certain that these are the exact bearings I removed from the top fixed flange race when I disassembled the bracket. My question is: what exactly is going wrong?

I was attempting to insert the fixed flange onto the spindle incorrectly, the result of a poor diagram made when disassembling the bracket. If anyone else finds this post and needs help reassembling a similar sealed cartridge bottom bracket, here are step-by-step instructions. I wiped down the components before taking the pictures for clarity.

Insert seal (notched side down) and pack large bearings onto spindle cone.

Drop fixed flange onto spindle and pack small bearings.

Insert cone, lock washer and hex nut onto spindle.

Reseal fixed flange (notched side up)


Can't shift down from 50T with clutch on, but can shift down with clutch off, why? Can't shift down from 50T with clutch on, but can shift down with clutch off, why?

I'm using sunrace 11-50 and XT RD-M8000 (SGS), finished setting up everything for absolutely perfect shifting, then realised the clutch was off. Turned it on, shifting is still excellent (but with the usual clutch effect) except it will not shift out of 50T. The shifter clicks, the RD stays put, same thing if I do multiple shifts down. I can however backpedal for a while after one downshift to drop the chain into the 42T, the RD then moves, after which I can pedal forward and carry on shifting down perfectly.

This is not a derailleur setup issue, not only have I got everything setup by the book, but I've played around with 4mm to 12mm gaps between the 50T and top pulley with B-screw with no luck.

My calculations (full formula including 2 links for derailleur, not rough estimate) showed that 113.4 (=114) links on the chain should be enough, I installed with 117 links initially, felt that was too much chain, removed 2 links and am using 115 now. Doubt it's chain length, can't see why everything would be fine with clutch off if it's chain length, but worth considering.

RD is just out of the box, so I doubt it's the Nm on the clutch, but going to check that out soon.

It's not a big issue, since there are only 2 to 5 (depending on conditions) places where I need/want the 50T and all of them are during the (mostly) climbing half of my local rides, so I can ride up with clutch off and ride down with it on.

Above all I'm curious why extra chain tension from clutch could cause this; even if the Clutch tension is too high and that is the reason, why would this happen? After all, it shifts even under quite a lot of load with clutch off (I avoid this bad shifting practice where possible, I was just testing!)

The RD-8000 is specified for a maximum tooth size of 46 (1x11-46).  Likely you are just exceeding its design criteria and reaping the rewards of DIY mix and match.

The clutch does not add tension. It add friction in one direction to resist a forward moving cage, but allows the spring to pull the cage back freely.  As the chain drops off a cog onto a smaller one, it has to briefly lift and this causes the cage to move forward against the clutch. The clutch is designed to slow this action - possibly in you setup just enough to keep the chain on the large cog and prevent it dropping on to the smaller cog. A longer chain will make little difference, as the clutch is friction based, so spring tension changes probably won't change the behavior.

Chainline is probably all you have left to play with. (You don't mention the bike, presume its 1x now, was it always 1x). Moving the chain ring out a millimeter or two might make a difference - or it might not.


What BMX bicycle to buy for both urban and rough riding? This is slightly related to my previous topic about Danny MacAskill's bicycle, but not necessarily bound to it.

I'd like to buy a BMX bicycle with the following requirements:

I want to use it only in the city
I want to be able to perform jumps / rough riding on it
I need to be able to jump at least 3 metres high jumps without coming nothing near to damaging the bike
My weight is 74 kg
I'd like to pay around 500 EUR, but I can pay more if necessary

Could anyone point me to how to look for a bicycle I need? I have absolutely no experience with this, so I don't even know where to start.

Rarely do you see people riding 'stock' BMX bikes - the bikes are as individual as the riders. Typically 'mummy' buys a 'stock' BMX and over time it gets more evolved, e.g. a frame with a longer top tube and fancy, bespoke parts.

In the UK 'Mongoose' branded bikes are probably the best stocked and even then it is rare to find a bike shop with more than a few of the models, chosen to meet price points rather than due to the virtues of the bikes. Invariably you get tyres for the riding you describe with soft rubber rather than chunky tyres of a harder compound for the dirt track.

Coming from a cycling background you might find it hard to be on a bike that has just the one fairly weak rear U-brake or sidepull (or no brakes at all). Therefore you may want to have a look at the almost-mainstream models that come with both brakes. These come with a 'rotor' in the headset so the bars can be turned 360. These bikes usually come with 'stump pegs' and typically weigh several metric tonnes. You can obviously take the 'stump pegs' off as well as the brake/rotor to get the weight down.

Only the department store BMX bikes come with wheels that are less than robust. Most BMX come with 36 spoke wheels and that is a lot of spokes on a 20" wheel.

The chainring size is something to look out for. Most of today's BMX bikes have a ridiculously small chainring. The sprocket is also absurdly small so the gearing is the same as normal. You save weight and have higher clearance with the small/small gearing. Stay away from older models with the big chainring.

As for where you are now, you can go the traditional route of getting an available bike, such as a Mongoose freestyle model, to pimp it over time to suit your riding style. Alternatively you can buy a frame/bike of beauty such as a bike by 'We The People' and, even if you don't take up riding it too often, you will have a beautiful bike to look at.

As with all things cycling it is the rider and not the bike. Some of those bikes that get thrown around in a gravity defying way by the experts are unbelievably heavy, probably heavier than a typical MTB or a fully equipped hybrid. Bear this in mind when you go to a LBS that stocks BMX or get something online.


A Cart for a Bicycle I was looking at building a Cart/cargo for attaching to the back of my bike.
Are you guys aware of any DIY kits or manufacturers that can  build it to my specifications.
I did look at some on the market, but they all seemed to be limited and are of less dimensions. I was looking for building something about 1.5*1*1(Length width and height).
Thanks for any suggestions!

It looks like this Wicycle kit may fit your needs. You buy the dimensional material (metal bars in this case) to whatever size you need locally, and the specialized cargo hardware is included.


Is there any benefit to riders on the front of a paceline? You can save a lot on air resistance by drafting a rider closely, i.e. riding close to their rear wheel.

What about the rider in front? Is there a benefit, a loss, or is there no difference?

Edit - is there any way or position ensuring front cannot feel any energy loss while you enjoy resting behind or speedup ?

Yes, it's small but real.  Aerodynamic drag in cycling pelotons: New insights by CFD simulation and wind tunnel testing Journal of Wind Engineering and Industrial Aerodynamics
Volume 179, August 2018 is an interesting paper on the subject, with both theory and experiment.  The introduction is a nice summary of previous work, including simpler cases, but many of those papers are inacessible without a university login, unlike the one I've linked.

Figure 9 and Section 3.8 are most of interest, especially Fig. 9b which indicates that a reduction in drag of 4% on the lead rider is possible.  Figure 22a shows a simulation leading to an even greater reduction in drag for the front rider.

You can see from the figures in the paper that behind a single rider there's a low-pressure region. You can regard this as sucking the rider backwards. By partially filling this low pressure region with another rider, its effect is reduced.


FD not for shifting gears? Complete amateur here but I took my 2021 Kona Rove Al650 to the shop today because the FD is not shifting. One of the mechanics told me that the FD on the Kona Rove is only used to adjust the chains and not actually for shifting gears. I clearly have two chainrings. I’ve never seen this system before. What is it called?

They very likely were talking about your front shifter's trim stops.
Your shifter has 3 or 4 positions despite there only being two chainrings. As you shift around in back, the angle that the chain enters the front derailleur changes. This can cause rub. The trim stops exist to change the front derailleur's position enough to eliminate the rub. In other words, when the system is set up correctly, you've got one or two stops in it that shouldn't be moving the chain. (Almost every STI now has 4 but I'm blanking on whether Claris is 3 or 4.)


Is there anything concerning about buying a half-price "test helmet" from my local bike shop? I just bought a Lazer O2 helmet and am loving it, but I got it half price from my local bike shop because it's a "test helmet". This means that people who want to test ride their bikes use these helmets, but the person I talked to mentioned that this helmet was not used very often. It is white and has the words "test test test..." printed over a top portion of the helmet- it does not look like a sticker. I am wondering if anyone has had experience with these types of test helmets and if there is anything I need to be concerned about. It doesn't seem like the helmet is any different from the regular O2 helmet, other than the print on the top.

Thank you!

A recent study investigated the impact performance of 675 used helmets (some as old as 26 years) without signs of damage.  (They collected 1500, and eliminated helmets with signs of damage). They all passed, except four. Three that failed were only made to meet the  old ANSI standard, and the only newer helmet to fail was a recalled model.

Because all of the helmets were used, some of the 675 would have been incurred some slight damage (e.g., being dropped, or bumped through regular usage) without showing direct signs of damage .  The fact only 4 failed, and those 4 had other issues, this suggests if you don't see visible signs of damage on a modern helmet, it is probably okay. In fact given the large sample size and consistent ability to pass the impact testing, I now have a lot more confidence in the quality of modern helmets than I did before.

For your helmet, makes sure to carefully inspect it.  If you don't see visible signs of damage you are probably fine,  assuming that the helmet was properly manufactured (i.e., NOT a grey market helmet), that it has passed all the modern certifications (i.e., check for the certification stickers), and that it was not a recalled model.


10 / 11sd compatibility I own a road bike with a SRAM Red 10 speed 110 BCD crankset and chainrings. I am upgrading the bike to the SRAM 11 speed shifters, cassette, chain and derailleurs.

Do I have to buy a whole new SRAM red 22  110 BCD crankset or can I just get the Red 22 outer and inner chainrings to fit my current 110 bcd arm?

In other words, will SRAM 22 Red 11 speed 110 BCD chainrings fit on a 2012 SRAM Red 10 speed crankarm?

thanks for all the responses. i realize that my terminology may be misleading. i actually wish to upgrade to the 11spd chainrings. what i needed to confirm was if they will fit on my my current red 10 spd spider arm i.e the hole dimensions are the same. if not i will have to buy the complete new crankset which is an additional US$226 vs just the chainrings. what i will do is purchase the small 11 spd ring which is less expensive and confirm that its holes match my spider

You probably don't have to change the chainset at all. An 11-speed chain and front mech will run fine with a 10-speed chainset.
A good article by Lennard Zinn who is the last word on mixing and matching drivetrain.
10 / 11 speed drivetrain compatibility

Dear Lennard,
I was really interested in your recent Tech FAQ columns where you mention compatibility between various 10- and 11-speed systems. I would like to make the move to 11-speed in the most efficient manner, cost-wise and in terms of using components I already have.
In a recent column you wrote that one can use the old SRAM Red 10-speed rear derailleur in an 11-speed set-up, as long as it is matched with 11-speed shifters. That makes sense, as the derailleur lateral movement is determined by the cable pull per shift and ratchet mechanism in the shifters, not by the derailleur. I wonder if an older 10-speed generation front derailleur will be compatible with the current generation SRAM Red left shifter (i.e., is the cable pull and leverage in the front derailleur the same between the current and earlier 10-speed groups)?
I do hope the answer is yes, as I have sitting in the basement NIB SRAM Red derailleurs (10-speed), that I bought and intended to use in a build, but time and work demands did not allow at the time.
— Sebastian
Dear Sebastian,
Actually, this statement you made is incorrect: “the derailleur lateral movement is determined by the cable pull per shift and ratchet mechanism in the shifters, not by the derailleur.”
Rather, the lateral movement is most definitely a function of the design of both the derailleur and the shifter. The rear derailleur’s shift-activation ratio—the amount of lateral movement of the rear derailleur divided by the amount of cable pull to generate that amount of lateral movement (i.e., the number of millimeters of lateral displacement of the rear derailleur per millimeter of cable pull)—is built into the derailleur. It is akin to the leverage ratio in a rear suspension system (i.e., the magnitude of rear wheel vertical travel per unit of rear shock travel).
The design of the shifter determines how much cable it pulls with each click. If you multiply the derailleur’s shift-activation ratio by the amount of cable pull per click of the lever, the product will be the distance the derailleur moves laterally with each click. In order for the rear derailleur to shift properly on a given cassette, that resulting product must be equal to the lateral spacing between the centers of adjacent cogs in the cassette (the “cog pitch”).
You interpreted correctly that a SRAM 10-speed rear derailleur (road or mountain) paired with a SRAM road 11-speed shifter will shift properly with an 11-speed chain and cassette.
As for the front derailleur, a SRAM 10-speed road front derailleur will work acceptably with a SRAM 11-speed shift lever, but a front derailleur is perhaps the least expensive part of the drivetrain, and SRAM’s 11-speed Yaw front derailleur is a significant improvement over its 10-speed predecessor. Since your SRAM Red 10-speed road front derailleur is new in the box, you might consider selling it and getting the Yaw FD.
― Lennard
Read more at http://velonews.competitor.com/2015/03/bikes-and-tech/technical-faq/technical-faq-10-11-speed-drivetrain-component-compatibility_362722#Lr6GsYmPACvo8CY7.99


Schwalbe Marathon Plus and Micheli Protek Max: what are the fundamental differences? The Schwalbe Marathon Plus and Michelin Protek Max are both tires that offer a 5mm puncture protection and a reflecting sidewall, which are both interesting features.

The price is not the same, the Marathon being the most expensive by a good margin.

What other caracteristics can be looked at to differenciate both tires? I'm thinking about rubber wear resistance or drying resistance, but the marketing put forward by both compagnies does not easily allow comparison.

Thanks in advance for any input!

The actual differences would be known only to people who have been involved in product development or sales, and they would likely be under a NDA. So, let's speculate.

Weight: Both are very heavy tires, but Michelin is still heavier and Marathon Plus is known to have "good enough" puncture protection.
Construction quality: The only known fact about construction is that Protek Max has lower thread density than Marathon Plus (22 vs 67). Higher thread density usually means lower rolling resistance and smoother ride but is more expensive to produce.
Reputation: Marathon Plus is known to be durable and to have surprisingly low rolling resistance for that kind of puncture protection. Nobody knows about Michelin yet.

All together, Michelin has to compete with price if they want to sell at all.


Can an imperfect hub make a disc rotor rub? I had a 160mm disc rotor on a road bike that was rubbing a bit in one spot, not severely, but enough for me to notice.  I've tried to true it a few times over the past couple months with little improvement.  I finally ordered a new rotor (sram centerline) and noticed it's also touching the pad, possibly more so than the old, but it sounds better under hard braking oddly enough.  I checked the new rotor before I put it on and it was straight.  I'm wondering if my hub is just imperfect and that's whats causing the alignment issue.  Is this common and if so is there a fix?

It could be a number of issues but I doubt you got a bad hub. Check to make sure your wheel is seated correctly in the fork. You could also try tightening/loosening the skewer to see if that may help align things. If all that doesn't work then you can try to realign the caliper if necessary. I wouldn't worry much if its just a little rub.


Need help getting the right derailleurs for a vintage 12 speed double What derailleurs do I need?

2x6 speed
52 and 42 tooth up front.
Crank set is Shimano 600

I believe the bike is a Raleigh Road Ace. I came here a month ago asking to identify the bike and now I'm aiming to restore it. I know nothing about road bikes so I don't know if all 6 speed derailleurs fit all 6 speed cassettes. Please explain as if I'm five years old haha.

Thanks.

These images will explain more than my words can.
https://imgur.com/gallery/LDbbS

There's no such thing as a 6-speed cassette. Back in the day, we used freewheels.
Indexed shifting was a new thing when this bike came out, and from the looks of it, this bike didn't have it. It has what I'm guessing are Campagnolo Triomphe or Veloce shift levers, which were not indexed.

Because shifter/derailleur/gear compatibility is necessitated only by indexed shifting, and you currently don't have that, you could throw any short-cage derailleur on this and it would work (or long cage, whatever).

If you want to get indexed shifting, then we're talking about something much more complicated.

For starters, your rear triangle is almost certainly spaced 126 mm, but you'll have a hard time finding a hub for an indexed-shifting system that will fit that--they did exist, but the bike industry moved up to 130-mm spacing pretty quickly (indexed shifting came out around 84-85, and 130-mm hubs a few years later), so either you'll need to get lucky hunting old parts or you'll need to have the rear triangle cold-set to 130 mm (you could maybe jam a 130-mm hub in a 126-mm triangle--different people report different results). Once you've done that, you'll need to buy a new rear hub, new cassette, new derailleurs, new chain, and new shifters. And some 11-speed drivetrains will require that you get a new crank to work well, if you go that route.


Cartridge bottom bracket with lockring on one side only NB There is an edit to this post added 06.02.2017

I need to replace the 68/118 BB on my Giant Rock (made around 2000 I think). It has a locking ring on one side only as shown in the photos. The problem is I can't find one like this online. The nearest I've found was on Sheldon Brown's website but I can only post two links/photos with my reputation so you'd need to google "Cartridges with a lockring on each end" if you're interested.

I want to order the right spares and tools the first time round (to avoid paying for two deliveries) so my questions are:

Do I need to get any special tools other than the obvious: BB tool and lockring tool?
What replacement part do I need? Can I use a BB without lockrings, a BB with two lockrings, or does it have to be a BB with just one? Specific model recommendations would be welcome but not essential - it's the type I need to figure out.

If it helps, the thread on the chainside crank (used to attach the crank remover) had some wear on it, so there may have been some work done on this setup in the past, but I don't know how to tell if there used to be a locking ring on both sides. Please do let me know if further info is needed to answer the questions.

bottom bracket right end (nearest to the chain)

bottom bracket left end (furthest from the chain)

Edit on Tue 06.02.2017

Hello, I have browsed the web for a bit longer, and came across some info which I'd like to share here. Hopefully it helps someone make a more specific judgment of what the crack is with my bike.

There are some shops and ebay listings offering a "semi sealed" bottom bracket:
http://www.ebay.co.uk/itm/BICYCLE-BOTTOM-BRACKET-VINTAGE-BALL-BEARINGS-STYLE-118mm-or-126mm-IN-BLACK-ONLY/331915747544

http://www.ebay.co.uk/itm/Raleigh-Bikes-Bottom-Bracket-Set-Semi-Sealed-Axle-118mm-Black-/141399887346

There is also this youtube video which I gave its 76th view and which leaves more questions than answers:

The sales listings quoted above don't seem to explain clearly what the difference is between an average cartridge bottom bracket
 (like a shimano bb un55) and a "semi-sealed" unit. In fact, most results I get on google for  >>"semi sealed" bottom bracket<< are from ebay and shops. The main point however is the fact that there is indeed a locking ring on one side only on these.

Now then, I can get a NECO B910 sold with the BB tool for £12, whereas a semi-sealed unit and a BB tool have to be bought separate and add up to at least £16. So the cheapest semi sealed is a few GBP more than the cheapest model without the single locking rings, and I'm not totally clear if I can use either, or only the semi sealed. I don't have the budget for error, so I would really do with some hints here. It seems I have four options really:

Buy a BB tool on its own, get my BB out and take it from there - I might do that if I don't get a definite response on here in a few days, but this will cost more if it turns out I could have bought the £12 BB combo in the first place
If someone is able to positively identify that the unit I've got can only be replaced with a semi-sealed BB, I will buy one of those from a source where it's cheapest to buy the part and a BB tool (with delivery)
Ebay listing 331915747544 linked above seems to suggest this type can be taken apart and bearings can be replaced while keeping the rest of the assembly - if someone can confirm that
, I will probably end up buying just a BB tool first to identify bearing size etc, but at least I will have a reason for it.
If someone is able to positively identify that the unit I've got can be replaced with that NECO B910 or another similar BB without a lockring on one side, I will get that £12 set. This could in effect be what CardMechanic says (thanks for your response), but he hasn't mentioned "semi-sealed", so I'm not sure he considered the option that one of these might be required.

Thanks in advance for any input!

Your standard cartridge and "loose bearing" bottom brackets have two threaded "cups".

Usually the right (drive) side cup has a lip on it, so it will only screw so far into the bottom bracket housing.  There is no adjustment, and no need for one, since the distance that the shaft should project outward is determined by the design of the parts.  And if the bottom bracket is a cartridge one often the right side cup is permanently attached to the cartridge.

However, nothing is perfect.  If the cups do not tightly restrain a cartridge unit it will move about and make annoying clicks.  And if the cups are loose in a loose bearing style unit the axle will wobble around in the bearings.

So one side (at least) is made adjustable, without the lip on the cup, but instead with the threads extending a few mm outward beyond the expected distance it should be screwed into the BB shell.  This adjustable cup is then screwed in "tight enough" to achieve the desired pressure on the bearings.  But "tight enough" is not generally so tight as to cause the cup to "lock" in place like a regular bolt, so the lock ring is added to allow the cup position to be preserved, in spite of the various mechanical pressures that would attempt to turn it.

Note that this "adjustable cup" is generally on the left side, allowing the adjustment to be accessed without interference from the chainrings.

The vast majority of "3-piece" BB setups, at least on lower-end bikes, are of this variety, with one "fixed cup" and one "adjustable cup".  For the most part these units are interchangeable, so long as the style of the axle end matches (and there are 3.5 different styles).  There will be a modest variation in the length of the right-side shaft, between 2-ring and 3-ring fronts, but most 3-ring bearing assemblies will fit 2-ring bikes, and likely a fair number the other way.

A few bottom bracket bearing assemblies have adjustable cups on both sides.  This allows for various things, such as a BB shell that is wider or narrower than normal, or desire to adjust the "chainline", moving the sprockets closer to the frame or farther away.  It also allows a single BB bearing assembly to fit several (slightly) different setups.


Can I use a SRAM Powerlink on a Shimano chain Have 9 speed Shimano chain that I need to shorten.

I don't have the Shimano pin so I need to go buy one.
Could just reuse the regular pin but I already broke one chain tool trying that.

I think the SRAM Powerlink would be more convenient.

Is it safe to use the SRAM Powerlink on a Shimano chain?
Or is there some other reusable connector (master link) for a Shimano chain?

As long as it's a 9-speed power-link, you can. I have chains in all bikes connected this way and find it most convenient method. The one made by SRAM is also the easiest to open.


Can an 8 speed chain fit inside an 11 speed Shimano 105 (RD-R7000 ) rear derailleur? I am using downtube friction shifters, I know my shifter's pull of 28.5 mm multiplied by the Shimano 105 RD's pull ratio of 1.4 gives me 40mm of travel, enough to traverse  the entire width of my 35 mm 8 speed freewheel. I am worried that my 8 speed chain will be too fat to roll across the jockey wheels of the 11 speed 105 rear derailleur...should I be ?
I have an 8 speed freewheel.

The internal width of the chain will be fine, as this has not changed in decades, so it will roll over the cogs and jockey wheels. The problem will be the external width of the chain.  It will probably not fit though the 11 Speed derailleur cage, and if it does is likely to rub in some gear combinations. According to Park Tools, 11speed is 5.5mm and 8 speed is 7mm.
On balance it is one of those things that might work, might not, where 'work' is something you define. If it works, mixing and matching components like this is as likely to end up with Claris performance at 105 prices as anything.


How much of a difference will I notice going from a Mountain bike to a road bike? I have a Mountain bike with 1.95 tyres on it. Most of the cycle path I take into work is fairly well paved/asphalted, I'm not going over any dirt tracks or anything like that although there is the odd bit of poorly maintained asphalt.

There are also a couple of hills that are steep but not long, for the most part it's fairly flat though.

How much of a difference would I notice if I bought a road bike for my daily commute?

You will find the journey a lot less effort, as you are dramatically reducing the weight of the bike.
You will also be able to accelerate much faster, as the rolling resistance will be reduced through the use of thinner tyres.
Your gearing is likely to allow for faster speeds as well.
If you previously had suspension, you will notice the ability to accelerate, brake and turn is much better, and more precise.
You will rapidly learn how uncomfortable bumps are so you will have to get used to dodging round stones, potholes etc.


Removing cushion from Aldi Bikemate Boodie seat I would like to remove the cushion from my Aldi Bikemate Boodie seat - it is unpleasant after spending the winter in a damp shed. There is only so much cleaning I can do while it's on and I don't want to expose the plastic shell to cleaning chemicals.

(Edit: Daniel R Hicks pointed out it looks like "Polisport Bubbly Maxi" and it is exactly the same seat, and it turns out so is "Raleigh Avenir" and others - they even keep the "boodie" embossed on the cushion. Clearly it's all licensing etc.)

I contacted Teknihall using the info on the product information plate - but I'm not sure if Teknihall are the original licensor or one of the many licensees. Anyway, they said they would look into this, they may still get back to me and I will update this question if they do.

The problem is that the cushion is held in place by a clamp/jaw which I highlighted in photos 5 and 10. It seems like it should be possible to slip the jaw off. I gave it a go and it didn't move. I'm conscious I will brake/strain the "tongue" that the buckle sits on if put any more force on it. I can see how there might an element of rotation involved in slipping it on and off. I can't see any catches/levers I would need to prize/lift.

The question is: has anyone removed the cushion on a seat like mine or similar? The tongue that holds the buckle is clearly a safety critical part so I don't want to mess with it unless I am happy my actions are safe.

0 Manufacturer's photo taken from Aldi's website - NB this photo was added after several people commented the photos are not clear.

1 top general view

2 top showing back of buckle

3 top showing front of buckle

4 clamp top close up

5 clamp top close up annotated

6 bottom general view

7 bottom seen from prong ends

8 bottom looking vertically up

9 cushion clamp - bottom view

10 cushion clamp - bottom view - annotated

11 product information plate

First, for what it's worth, this is probably a Polisport brand seat, possibly the "Bubbly Maxi" style.  Contacting Polisport (however one might do that) would be more likely to be productive than talking to Aldi.

Unfortunately, I can't make much sense of the pictures.


Titanium bolts: Preventing bonding? I picked up Ti bolts for my [brake] rotors, and am aware of TiPrep but wondered what other more commonly found (and likely cheaper) alternatives are there?

Scouring the 'Net, I've read about copper anti-seize...  One co-worker who does auto-moto stuff suggested zinc anti-seize?  Loctite in general doesn't appear to be recommended, though they do have a copper based product.

You use the anti-seize compounds on bolts where you would normally use grease. For rotor bolts, use an ample amount of blue threadlocker (loc-tite), even on Ti bolts. It acts as a sufficient barrier between the two pieces of metal and prevents oxidation and bonding. I've done this on others' bikes as well as my own with no instances of bonding to report. You don't want your rotor bolts backing out and anti-seize compounds are not suited to prevent that from happening.


Safe to ride with Kenda 27 x 1/38 inch studded tires in snow/ice? I currently have Kenda 27 x 1 3/8 inch tires on my road bike. I live in a snowy, icy city and am a bike commuter in warmer months. I would like to occasionally commute this winter. I am wondering about the safety and challenges of riding with this size of tire width? I can have these tires studded at a bike shop in town, but I am hoping for advice whether this is a good idea. We have some ice and snow on the side roads here, as salt is not used.

It will depend largely on your handling skills and the conditions of the snowy, icy city you live in.

Narrower tires, like what you have will cut through small amounts of snow quite easily, but will quickly bog in deeper snow and can be difficult to control when you can't see irregularities underneath the snow. Since they also need to be run at higher pressures, they tend to be a bit twitchy, which is fine on slick even surfaces, but can easily cause slips and crashes where surfaces are uneven (transitions between roads, bike paths, sidewalks, etc).

I often commute in the spring on narrower studded tires, but am very careful around transitions, or uneven slick surfaces (jumble ice).  They are great for icy patches left by melt/thaw cycles, but definitely less forgiving than a wider tire.  By contrast, I can maintain more speed or jumble ice and the like with the studded tires on my fat bike.

TL;DR I skip using them on days where you have deep snow, or in areas likely to have slick and uneven surfacing.


The width of Profile Design Tri Stryke saddle (with cutout)? I am interested in Profile Design Tri Stryke Saddle (with cutout), however there is no specs on the website, nor the manufacter answers my e-mail. So maybe somebody has this saddle and would be so nice and tell me what is the width of this saddle?

Thank you in advance.

Assuming you mean the width at its widest point, 122mm as best I can measure.


Zip ties to hold smart-lock on frame I've recently bought a smart lock for my bike that can be mounted directly on the frame. Problem is that my frame has no hole for screwing it on the frame. So I improvised with with 3 zip ties on each side. Question: will it hold or should I remove it and use some other system? It's been a week so far and it held quite well.
Thoughts?

Here's an image of the lock being used. As you can see the 3 holes where the zip ties are going into to then tie against the frame:

Zip ties don't last forever, so you'll need to keep an eye on them and replace them periodically. P-clips would probably work.


What can one damage by bending the wheel? What parts may be damaged by bending rear wheel manually with very high force?

My father bent rear wheel several times with such high force that the tire contacted the seat stays. Could he have damaged or worsen any part of the wheel (hub, hub axis, bearings, spokdes, etc)?

I complained about the way of transporting my bike in his car (lying horizontally on rear wheel) so he tried to prove there is no influence on wheel centering and hub health.

Is it okay that the wheel can be bent slightly with proportionally high force?

Bike model: Author Codex 2015, wheels: Author Radon, unsure about type of the hub.

There is probably no damage.

In wheel-building, one of the ways to relieve torsional stresses in the spokes is to lay the wheel flat on the ground, so that it rests on the hub. While you press the rim on the ground at the 6 o'clock position by your knees, you put all your upper weight via both arms on the rim at about the 10 and 2 o'clock positions. You feel the elastic deflection, which depending on spoke tension and number may be about 1 cm. The spokes on the de-stressed side are able to unwind the torsional stresses. You rotate the wheel in small steps on both sides. There is no damage to either rim or hub.

Look how this process was cleverly implemented on a luxurious wheel truing stand (at about 2:10)

As long as you keep within the elastic deformation range, there is no damage. The characteristic of the elastic range is that the wheel returns to its original shape if the force is removed.


Braze on or what sort of clamp on a Cinelli frame? I'm seeing a ridiculously good local deal on a Cinelli Experience frame. I think I'll build it up with entry Campagnolo stuff (also seeing a deal). I am mildly confused about the front derailleur attachment. Some listings for the complete bike talk about it being braze-on, but I sure don't see that in pictures: I see some sort of Cinelli specific clamp. Is a normal 35mm Campagnolo clamp front derailleur just fine? What is this?

The Cinelli spec for this bike lists it as "clamp on" and your picture definitely shows a clamp on style front derailleur.

While it does seem like the factory build comes with a Cinelli branded clamp, if the frame you are buying is missing that part, you shouldn't have any trouble with a campy clamp, like this one:

If you are buying a a new campy gruppo, make sure you get the clamp on style front derailleur.  You can find just this part as well on ebay or an online parts supplier.  There are also adapters for braze on to clamp on style derailleurs, in case you found a good deal on a used campy gruppo with braze on front derailleur.


Railroad Power lines interfering with Heart rate Monitor I have two heart rate monitor chest straps from Sigma and one from Garmin. Everytime I pass close by a trainline the numbers on my HR-Display go bananas. I'm about to go insane because of this, is there anything to do against this? Buy something new? Or throw it all in the bin..

Hmmm... I smell a science project!  If the field is really strong be aware that optical may not work either because the chips/wireless probably aren't shielded anyway. Assuming you don't need laps for training, you could try hitting your lap button so at least you know when the event happens. I suppose you could try an experiment by taping aluminum foil to your chest covering the monitor pickups but not the wireless unit. That might tell you if the shielding issue is in the leads as I suspect or in the main unit that picks up the wireless. Ask yourself if the speed/cadence monitors wireless signals are being received to indicate whether an optical monitor might work.


What are velcro alternatives for frame mounted bag? I don't like velcro straps on my bike. They are constantly shifting and rubbing against it. They catch dirt. They cover frame stickers ;) A few days ago I've seen a frame bag that appeared to be connected to the frame without any straps at all. Just like one in this answer:

Photo Bikerumor
I wanted to ask how is that possible, but I believe the more useful question would be what are alternatives to velcro? Preferably without its flaws, that is:

Not sliding, rubbing and moving against the frame
With less potential to build up dirt deposit
Less visible

For the sake of completeness, please include ones that require specifically built frame. I don't have one, but future readers might.

I do not know of any commercially available products alternative to velcro, but I'm a DIY-er, And have successfully mounted some accessories to the frame and handlebars using hose clamps.
Their advantage over velcro straps is that they can hold more weight and can better stabilize the load. A strap of old inner tube is enough to protect the paint. Since the clamp does not slide, it does not rub against the paint. The clamps are ugly, but allow for semi-temporary solutions.
Another option can be specially made plastic clamps (Similar to the ones used to mount reflectors and accessories). Maybe 3D printed. They would also be "visible" but could be designed to be more eye pleasing and to clamp on areas that do not obscure the logos.
Another option is to fabricate a bag that can be mounted to the water bottle cage eyelets. Some frames have two sets: on the upper side of the down tube and on the front of the seat tube. The bag would need an inner frame to be bolted to these eyelets. A simple aluminum flat bar should be enough. If only one pair of eyelets is available, only a smaller bag should be used as to not overload the bolting points.
For those who order a custom frame, this could be a serious option (ordering specially placed eyelets).
For those willing to modify a frame, eyelets can be installed appropriately. (Depending on frame design and material).
Edit / afterthought: Another way could be to build an inner structure for the bag that can be "press fit" into the bike frame or may have some bolts that make it "expand" so it tightens inside the front triangle.
The frame would need to have the inner shape of the front triangle and half-pipe (-ish) profile to avoid sliding out, at least on contact points. On the outside, the contact points should have rubber or similar material to avoid sliding.


SRAM X4 MTB Rear Derailleur H-Limit screw maximum open, but still on 7th Cog? I own a 6 months old Rockrider 5.2 mountain bike.

Everything was great until recently I noticed that the Rear Derailleur of my bike doesn't reach the highest gear cog, which is 8th. Its always stuck on 7th.

I tried opening the H-Limit screw completely and it even came off, but my chain doesn't still move to the highest cog.

I have a beautiful Sunday morning ride planned in 6 hours from now. Can anybody help?

First thing to check is if your rear derailleur is bent. If that is not the case, check the cable tension is not too high. Is the shifter acting funny (like hard to shift)?

See this link to see how to do adjustments: http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur


Which spokes should I get for an Expresso Coaster Brake with a Velocity Deep V 700c I'm working on my first coaster project with an old 700c frame which I want to make really clean using an Espresso Coaster Hub.

http://www.espressowheels.com/griptape.html

Rear black coaster brake hub with 32 holes. Includes 16T chrome sprocket, chainstay fittings, nuts and bolts. Hub width: 120mm,
axle diameter 3/18".

I got the Hub from a friend and I want to make a nice rear wheel with a White Velocity Deep V 700c
http://www.velocityusa.com/product/rims/deep-v-622

I don't have experience building custom wheels, so I was wondering if you know which length spokes I should get to have it built.
I emailed espresso but haven't heard back yet. I live in the Hague in the Netherlands so any recommendations as to where I should get the wheel built and how much I should pay would be great.

Someone recommended I just take the rim and hub to the bike shop and have them pick the spokes and make it rightaway. Is that a better option?

Since you live in the Hague: There is a good chance these guys have experience with espressowheels. For a more general answer: just go to a bike shop with the hub and rim and they'll be able to help you.


What does marking like "aq/ar" on the sprocket mean? Shimano sprockets are marked with short strings like "aq/ar", "bg", "as/au/be" and others. For example, "bj bk" can be read on the image below:

It looks like they mean the hyperglide series to which this sprocket belongs. Is there anywhere a list of these series?

This has nothing to do with dates.
Shimano introduced cassettes on their road racing groupsets first. I.e. Dura-Ace. The first Deore XT lacked this.
The first Shimano MTB cassette was CS-M732:
https://si.shimano.com/api/publish/storage/pdf/en/ev/CS-M732/EV-CS-M732-0969.pdf
This had
B-type: 12-14-16-18-21-24-28T
C-type: 13-15-17-20-23-26-30T
Not sure what A-type was.
Anyway, they made lots of cassettes so 26 letters wasn't enough so they switched to two letters. (And I think it's MTB-specific, for cassettes, road cassettes do without them)
Chainrings had a similar thing - at one time they had 3 types for road, A, B and C
https://www.thetallcyclist.com/2013/01/the-truth-about-the-shimano-a-and-b-type-chainrings/
But now they use a two letter code
https://si.shimano.com/api/publish/storage/pdf/en/ev/FC-9000/EV-FC-9000-3325B.pdf
The code represents the entire set of sprockets or chainrings, and is significant because of 'hyperglide', i.e. the ramps on the sprocket or chainring. The number of ramps is equal to the gap to the next sprocket or chainring, for efficient shifting (if you fit a sprocket designed for a different larger sprocket, then shift performance from that sprocket will be poor). Technically a chainring or sprocket could be defined in terms of the larger ring/sprocket that it shifts to, but I guess writing '34/50' on a 30t chainring is more confusing than writing 34 MA.
An 11t (or whatever) sprocket may have multiple codes because there may be multiple 11-13.... cassettes for a given speed (the letters are specific both to the gear range and the number of speeds (so a 50/39/30 triple chainset had a different code for 10-speed rings than 9-speed).
Sprockets with the same codes should be interchangeable across cassettes (so you could fit an XTR sprocket with the correct code to your cheap cassette), but materials/weight differences are present. Shimano have lots of incompatible chainring designs OTOH and I suspect that chainrings of the same fitment have the same code, e.g., R9100 chainrings are incompatible with 9000 chainrings, and the former for 50-34 are marked 'MS', the latter 'MA'. The cheaper RS510 chainset also uses 'MS' for 50-34, so likely would fit to Dura-Ace and vice versa (though the RS510 rings are much heavier).
If you go through all the chainsets & cassettes on si.shimano.com you could come up with a list, but it doesn't seem particularly worthwhile to do so.
bj is 10 specifically numbered cogs 11-34t, and bk is likewise 11-36t, and for 10 speeds only - a 9-speed 11-36t is called CB (11-36t 9-speed was introduced after 10-speed 11-36t, so this is simply a matter of going up in increments of one letter for each new pattern Shimano made, across all speeds. 11-36t 9-speed cb is just the same as 11-34t au but with the 34t switched for a 36t, and since there were many 9-speed cassettes made before 11-36t was a thing, probably you won't find 'cb' on many 9-speed sprockets, but they are identical to 'au' except the last two cogs.)