Changed shifters and chain isn't in same spot My friend changed out the shifters on his bike and his rear derailleur isn't on the right sprocket based on what his shifter says. How can you fix this?

This happens everytime one replaces a component of the drivetrain since the original cable position is rarely restored.
He needs to do something called indexing the gears. It is a common procedure and there are many good tutorials online explaining how to do it much better than I could. Here is one I'd trust-


How to remove existing fluid before bleeding disk brake I've found lots of tutorials on how to bleed the disk brakes. And in all of them there is  nothing about removing existing fluid.
I'm quite afraid that when I start to bleed brakes the existing fluid will be mixed with a new one.
Is there any special procedure to remove the existing fluid and clean the cable?

You don't need to remove existing fluid prior to bleeding. Unless you use two incompatible fluid types (for example replacing DOT 5.1 with 5), mixing an existing fluid with new one is completely normal and part of standard procedure. The only situation where you may want to remove the old fluid completely is if you know it has ben heavily polluted with water. But even then normal bleeding procedure is enough to have satisfactory results.

During a standard bleeding procedure you push the old fluid with a new one and they don't have even enough space to mix together. If you do want to remove the fluid before, just push the old one with air instead of new fluid. It may take a few attempts to get rid of everything, but the result should be satisfactory.

And if you're going to fill the system with an incompatible fluid, such procedure is not enough anyway. In this case you would have to take the brake apart, clean everything with alcohol, let it dry out and put back together (paying particular attention to rubber parts). Also note, sometimes a given brake won't accept other kinds of fluids because of its design. In some cases o-rings can be damaged if wrong fluid is used, even if they are clean and dry.


Does rim size make a difference to chain length? I plan to upgrade my bike to 1x10 from a 1x7. I also want to learn how to build a wheel.

In order to archive this I need to change the hub on the rear wheel, but I am waiting for the hub I need to arrive.

I plan to use my spare thin 650b wheelset then install my chain so I can ride in the meantime. Does the difference in rim size affect the chain line so much I won't be able to use my 700c wheel once I have built it?

I plan to take it to a place in stockport so I can be supervised.

The rim diameter of the wheels has nothing to do with the required length of the chain on a derailleur equipped bike.

That does make a difference is the size of the chainrings and cassette sprockets. If you are using the same cassette on both the 660b and 700c wheels then the chain length will not need to be changed.

You dont say when in this process you are switching from 1x7 to 1x10. You will of course need a new 10 speed specific chain when you upgrade to 1x10.


What's a good setup for an experienced but rusty cyclist training for his first triathlon? I've got my first (sprint) triathlon coming up at the end of July. I need a bike to train and race on. I'm comfortable on both road and MTB style bikes, but haven't ridden on either in several years. I could see myself using either style well after the tri is over. It doesn't seem like I should spring right into a tri bike since that's a pretty specific setup and I wasn't too comfortable on the one I test rode. I've also seen a tri-cross bike that looked like a good combination of a road and off-road setups, though I haven't had a chance to test ride one yet. My immediate goal is just to finish this upcoming race, but I would like to continue biking more afterwards and that may or may not include future triathlons. I've got a budget big enough to put me on an entry level tri or a mid-level road bike. Or should I just go with a generic road bike and be able to get an entry level MTB bike too?

I'm not necessarily looking for a specific make/model (unless there's a hybrid you think I should try), more for what would be the best most practical configuration given my needs.

You probably don't want to spring for a specific time trial bike straight out of the gate - you might hate the triathlon experience, for one thing! Given that you're planning on using the bike after this events, albeit possibly with other events down the pipe, I'd be looking for something that you can get the best use of after the event.

So a road bike would seem to be the better bet - possible with a set of clip-on tri-bars; while not everyone gets on with them (not all road bike/ride combinations work with the correct geometry) they are generally considered faster - you're in definitely in a drag-reducing pose and they force you to stay still a lot more, which is better, too.

A tri-cross sounds, erm, intriguing. A time trial/triathlon bike will be set up to encourage a mono-position with speed, probably with a longer, lower back/body position. A cross bike generally has more clearance and encourages a head position almost over the bars, a shorter top tube and more clearance to enable better control on a uncertain terrain - these would seem to conflict ...

Over the years I've seen triathlons done on many types of bikes - even sit-up-and-beg shopping bikes with a basket! You won't be doing it for speed, but you'll finish.

Use the bike that you would think you'll get use off after the event. This will result in several things:

you'll have spent your money on something you'll use
you'll finish the triathlon
you'll have set yourself a (beatable) target time for the next event
you're going to be in a much better position in a few months, after the event and after a bit more training, to know what'll work for you.

Then get all of the above: once you start racing, commuting, shopping and training on the bike you'll be able to justify a time trial, commuter, road and MTB ... and even then you'll probably find another type you're missing!


How long does it take for one to get settled on a new saddle? I recently switched from a Selle Royal Seta T1 saddle to a Shimano Pro Falcon Anatomic saddle with a cut-out. It's lighter, wider (152mm), and has lesser padding than my previous saddle. The first ride I did with it was 100-km ride, in which I was on the saddle for around four hours. Apart from pain around the sit bones area, it was comfortable. To date, I've ridden 163km in total on the saddle, so three times in total, but every time I have ridden it, my sit bones have hurt.

I am wondering in general how long does it take for a saddle to break in, so to speak. Or, is this a case where this particular saddle isn't right for me?

I'm a heavy rider at 88kg, and I ride mostly in the saddle. I chose a 152-mm wide saddle because it more closely matches my sit bones measurement, which came around 15cm.

Thank you.

A 100 km ride is too much to do on a new saddle -- I'd start with 30 minutes rides, hour tops; not too hard. You also need breaks between rides -- riding 100 km then 30 km every day after will probably start you sore and keep you sore.

The saddle won't really change appreciably (break in) as you use it; break in is really for leather saddles which can break in like baseball gloves over time (and even then, theres only so much that can happen -- it either will fit or won't). Either you'll get used to it after a few rides or not. Many better bike shops have a return period for saddles that is long enough that you can probably get in 5-10 rides to get an idea if its comfy or not.

It's a highly personal decision, with body type, bike type and clothing choices coming into play.

Also, make sure the saddle is properly adjusted -- this means adjusting angle, fore/aft position, height, etc; switching saddles isn't as simple as just putting the new saddle in exactly the same position as the old one. You may even end up adjusting the handle bars a bit; saddles can feel too narrow if you have to sit too far forward.


Bicycle trailer for a standing passenger? Have you seen a bicycle trailer for a standing passenger?
I came across the following image on Pinterest but cannot locate the source.
https://www.pinterest.com/pin/453737731186785705/

Appears to be asian based on the rider/passenger, and that pintrest links it to arrow-yokohama.no-blog.jp  but that website no longer exists.

The wayback machine gives us this link to 2013.
  https://web.archive.org/web/20130809133057/http://arrow-yokohama.no-blog.jp/

Store Name: "ARROW's bicycles and classics"
Store Owner: Kazuto Kobayashi ( Roundabout / OUTBOUND shopkeeper
Store Location: Kichijōji, a Neighborhood in Musashino, Japan

There was a youtube link to  https://www.youtube.com/watch?v=lt75V_C5JOI  but that account has been deleted.

I've also found this alternative image:

and a reverse image search on that returns https://sumally.com/p/437518

The bike's name is  ARROW CC Rider and that matches the maker's name "arrow"

  36,750 Y is around $350 USD in 2020.

  Product description
  The person in the back grabs the handle and stands on the step.
  Light and comfortable standing (riding) comfort. You can also use it as a shopping cart by attaching a basket.
  Please ride cool as a new play tool for the outdoors.
  (General public roads can also be run.)

In my opinion it won't go fast, and steering will be compromised because you can't lean the bike very much.   It looks like a bigger version of riding a BMX with a passenger on the pegs, a`la:


Is a "universal" rotor compatible with all types of disc pads? What is a "universal" disc rotor? One that is compatible with all types of brake pads?

Every brake manufacturer recommends only using their own rotors, so this is another case where the answer depends very much on who you ask.
In general, here is where rotor cross-compatibility can go wrong:

Some inexpensive Shimano rotors have less hardening and are designated "resin only." They in fact wear very fast if a metallic or semi-metallic pad is used.
Magura rotors are 2mm thick and more or less everyone else's are 1.8mm. Using a thicker rotor than a caliper is designed around, along with unworn pads, could get you into situations where you don't have enough air gap to play with even with the pistons all the way in. Such issues come up rarely in practice however.
Different calipers can place the size and location of the pad contact patch on the rotor a little differently. It seems like in practice there is not a ton of variance, but there is some. Someone trying to design a universal rotor would be trying to make it big enough that the top of the pad on any caliper never overhangs the rotor, but the top of the rotor can never interfere with any caliper.

The main question with the idea of a universal rotor design is whether, given an on-spec location of the brake mounts, is there a magic number for the exact outside diameter needed in the last point. I don't know the answer to that. But for practical purposes, all of the above issues are rare, most rotors are designed to capture some aftermarket sales as generic repair parts, and it's all pretty cross-compatible as long as it's not resin-only or Magura.


What’s a good way to carry a kid’s bike on an otherwise full bakfiets? I have a Workcycles KR8 bakfiets and the 3yo just got his first pedal bike.

We wanted to take him and his bike for a fifteen minute ride to the park where he could ride by himself, but chucking his bike into the front damages the box on the bakfiets, and won’t work at all when his infant sister comes along for the ride.

Has anyone seen a system for mounting kids’ bikes on a rear rack, or maybe off the sides of the box of a bakfiets? A Follow Me does more than we need and is quite expensive.

Option 1 - In the bin, forks over the front edge, with the front wheel removed and stowed inside bin.  Front two kids won't fit, and you'll have to mind that the steering isn't limited on the cargo bike.  Advantage, second bike goes on the other side.

Option 1b- same as above but hang it on the outside of the frame.  A short support that crosses the top of the bin would provide somewhere to hook the frame onto.  Pictured facing backward, but might go better the other way.   The inboard pedal could be a problem.

Option 2 - Extend the bin's frame and lean bikes on that.  Downside, its wide and involved modding your cargo bike.  Some kind of insert into the end of tubes might be adequate.  Upside, still carry 3 kids.

Option 3 - Add a rear rack (yellow) and strap the bike there

Option 4 - No picture.  Put the bike in a backpack like a tramping/hiking frame pack and carry it that way.

Option 0 - Three years is probably a bit small to be riding on the road, but riding a bit on the footpath may be ideal - depends on your location.  I like this one!

Upside, more room in the bin.  Kid gets exercise before you get there.  Sets a good example

Downside, you'll have to think for him while riding, so it will be extra slow.  Could double/triple your travel time.

All these answers will require some level of padding in appropriate places.


Unicycle recommendation I know that this is a 'bi'cycle forum, but I'm going to chance it and ask for unicycle buying advice.

What should I look for when buying a unicycle? I probably will do some leisure riding with it, maybe ride it around NYC instead of walking.

Probably the most important point is that it should be dirt cheap. Particularly if you're like me and try it briefly, find that it's uncomfortable when you have to involuntarily dismount and never reassemble it after a move.

Other than that, large wheeled unicycles are apparently easier to learn on. They are also faster (assuming ungeared), but not as maneuverable.


Rear disc brake rotor rubbing against caliper frame mount? I have bolted the rotor to the rear wheel hub and the caliper mount to the chainstay , however...

when I fit the wheel in the dropouts, there is no space between the rotor and the mount. The wheel won't spin freely.

I can't find a solution yet. Am I using a mount of the wrong width? I haven't attached the caliper yet.

I have a 2010 Gary Fisher that Trek recently warrantied. They provided me with the entire rear triangle of a 2013 Superfly, which by all appearances seems identical to my old triangle. There are differences though. Most notably with the new drop-outs. They are deeper than the original. By just enough that I was also having your exact problem. The fix - recommended by the mechanic at my local bike shop - was a simple, external star lock washer placed in between the axle end cap and the drop-out.


Change in setup to stop handlebars jack knifing I picked up a new fat bike recently took it on the first ride, just some light trails felt good however during corners the bars feel like the want to collapse in towards the way I'm turning. Not sure if what part of the setup is causing this, but hoping to tweak setup to minimize this. Here are some of the things that came to mind.

Shorter Stem
layback seatpost (thou I feel this may make things worse)
Smaller tire up front (but that kinda goes again the laws of mtbing)

Anyone been able to rectify this problem? Cheers!

bike in question: https://www.za1e.com/index.php/product/northrock-xc00-fat-tire-mountain-bike/

I suspect you just have to get used to the different sensations on the new bike, including is steering geometry, determining how much the wheel has to be turned for a given turn radius.

A different bike from what I'm used to always feels weird at first, particularly when steering. Heck, changing, say, the saddle height by more than an inch on the same bike can feel weird.

Steering is inherently counter-intuitive. After all, to turn right, you briefly steer left (whether consciously or not)!

These fat tires are inflated to low tire pressures, and have a high side wall height. Of course, that is going to affect handling. Anything that affects handling will give you a feeling, to which you react, to which the bike, in turn, reacts, amplifying the surprise.

Steering probably lags a bit on these fat tires compared to narrower ones due to the flexibility they introduce between the road and the rim. Say we are initiating a right turn. The front wheel briefly steers left, inducing a fall to the right which produces the necessary right tilt. At that moment, the steering is supposed to recover to begin turning right. If that recovery lags a little bit due to a squiggly, thick tire, that induced fall will continue a moment longer, leading to a sharper turn than anticipated.

If you feel you're going too sharp into a corner (say, right turn), you might subconsciously straighten the wheel slightly (effectively, making a slight left turn relative to the ongoing right turn). But that will induce a counter-steer that takes the bike tighter into the right turn, which then amplifies the original sensation.


Electric Bike Wiring? I have a generic 1000 watt hub motor that is new and it has never been used. I ordered batteries, but I didn't have cables to hook everything up properly. I tried one battery without charging it and I didn't get so much as a flicker of light. Do I have to have all batteries charged before any indicator light would come on? I am hoping this bike hub motor is going to work and I am charging the batteries one at a time. Can one battery be used to see if things will function on this bike or do I have to wait until I charge the complete set of my batteries making it 48 Volts?

Your 48 volt motor probably uses some modern flavour of lithium battery.  It will probably refuse to run on anything less than 44-46 volts (actual numbers may differ) and this will be in the controller's manual.

If you're using 12 volt SLA lead acid batteries, then they must not be discharged below 10.5 volts per battery, which would be 42 volts in your scenario.

To get 48 volts, you will need 4x 12V batteries in series not parallel.  12V batteries in parallel will still only give 12 volts, just a lot more current for a lot longer.  Since your motor is 48 volts it won't even start on one 12V battery.

I recommend you use the fattest wires you can to link your batteries.  Electric cars eschew wires in favour of busbars for added cross sectional area.

If this sounds like alien gibberish, you should enlist the aid of an electrically-minded assistant.

As an aside, you'll need to change a lot of how you ride once you have that much power on tap.  Riding in the door zone becomes a game of Russian Roulette, and you'll have to ride much more defensively, which means scanning ahead, eyeballing possible threats, and anticipating what might happen.

Also some locations would call a 1000 watt motor an electric motorbike, not an assisted pedal bicycle.  You may need to check this out.


Converting kid trailer to cargo trailer I just purchased a kid trailer to convert as a utility trailer.  I paid $75 for it used.  I could not find a cargo trailer for under $200 plus shipping (probably large).  The trailer is also rated up to 100 pounds (which is actually more than the cargo trailer 75 pounds).

I was wonder if anyone had converted a kid trailer to a cargo trailer before and what the best way to do it is.

The frame is:

2 Feet Wide
30 Inches Long

Here are some pictures:

(Note: my trailer does not have the bar or wheel shown in the picture).

Update:  I have removed the fabric from the trailer to get a better look at the frame.  The fabric is still in tact so it would be possible to put it back on the trailer.

I would cut a bit of 10mm or 12mm plywood to fit underneath of the main frame section and use cable ties to hold it onto the frame. Probably at the level of that bar across the back of the trailer.  That gives you a lip around the platform as well as a very slightly lower centre of gravity. Having lots of cut-outs where things are attached to the button of the frame isn't too much of a problem.

Ideally you'd find a plastic bin that exactly fit into the space but that's very unlikely to be possible. You will most likely find that the bin you get either sits too low and scrapes on the ground, or is too small on one side to work properly. If you go this route I suggest getting one the right width to sit on the main frame members and not worrying too much about how long it is. Having two bins next to each other might also work.

I think keeping the cloth cover will be handy, it will help keep your load in place as well as giving you some shelter from light rain.

Be aware that kiddy trailer load ratings are not the same as cargo trailer load ratings. No-one is expected to add exactly the load rating of children (look, it holds 2.3 children!), and people tend to be more gentle with children than with cargo. So a 30kg cargo trailer will probably hold the same weight as a 50kg rated kiddie trailer before it starts falling apart.

The reason they cost so much is that people won't buy a cheap, heavy, solid trailer. Instead they buy cheap, light, flimsy trailers and wonder why they fall apart. I built 12 of the heavy style and it took more than a year to sell them even though they cost the same as the flimsy junk ones. That as an educational experience for me.


What percent of crashes are due to bicycle failure? I find myself avoiding steep/fast downhills. Not because I'm afraid I'll lose control, but because something might happen to my bike that will send me face-first into the pavement.

Are there any statistics on this?

Edit------

By "crash due to bicycle failure", I mean a crash that would not have happened if something hadn't happened to the bicycle. This would include, for example, pounding your bike over bumps, resulting in the stem breaking. This would not include losing control because you pounded your bike over bumps.

By "crash", I mean an accident serious enough to be documented. If you fall over at a stoplight because you couldn't unclip, that obviously won't be documented and therefore doesn't count as a crash.

There are some statistics available from Great Britain for Contributory factors for reported road accidents. Below are the 2014 figures for Pedal Cycles, the first column is number and the second is percent.

Note that only reported accidents where a police officer attended the scene are included in the statistics. This Wikipedia article has some details of the methodology used to collect the statistics.

The complete data set is available here. The data above is taken from the table RAS50005 - Vehicles in reported accidents by contributory factor and vehicle type, Great Britain, 2014.


Does a hybrid truely have a wider tire or does a mountain have a wider tire? I'm looking around my local bike shop and saw that the hybrids have a slim tire while a mountain has a more fatter tire. And when i researched it says the opposite. Please help me.

What you saw is generally correct. In order of increasing tire size by bike type, it roughly goes:

road bike
hybrid
mountain bike

Of course there are exceptions and variations on these bikes that fit in that continuum, but as a general rule for tire width it's pretty accurate.


Where can I find the maps my Garmin Edge 305 made? Back between 2008 and 2010 I used a Garmin Edge 305 on my road and mountain bike. This was before Strava and overlays of routes on Google Maps so I would like to recover these rides and save them into my Strava.

The Garmin is long gone, and the computer I had the software installed on has been long since replaced. However, I do have a full backup of the hard drive. I was wondering what kind of files would the Garmin software have created, and where it saved those files. I do not recall the name of the software that was used. However, I do remember it being pretty crappy and laggy. This was most likely all done on a Windows XP or Windows Vista.

My questions are as follows:

1 - Did the Garmin save each route as a file?

2.1 - What type of file was it? Were they bundled in one big file?

2.2 - If so, what folder would I found that file?

The Garmin Edge 205/305 Owner's Manual makes it clear that any data that was not saved using the Garmin Training Center Software would be overwritten when the device is full.

The Garmin Training Center Software was last updated Aug 25, 2011. The Windows version ran on XP, but it can still be downloaded by following the links. You'd have to test if it will work on a current OS (but see the next para).

Garmin has a page explaining Where is the history data for Training Center located? That page seems to suggest that the software works on Windows 7.

If the data you want is present on your backup as .TCX files, then you can just upload it to Strava:

  Works for multiple .tcx, .fit or .gpx files 25MB or smaller. Choose up to 25 files.

If you can't see .TCX files then you'll have to dig deeper. From what I see the data can be stored in .TCD files, perhaps compressed a la zip. Install the Garmin Training Center Software and see if it can extract the data you need.

Good luck.


What is the purpose of landing on the rear tire? Throughout the entire Kranked series, riders are doing insane jumps and drops. What puzzles me is that, despite beginner advice to land both wheels (nearly) simultaneously, about half of the landings are as seen on the first several seconds of the linked video:

Land on rear tire
While the front tire descends to the ground, perform a disproportional movement with the body - the hips move little, the upper body moves a lot.

I very much doubt those drops look like that, because the riders are unskilled. So - what is the usefulness of landing rear-first, provided tire placement precision is not a concern (i.e. not hopping around)?

Landing on the rear wheel is a safe bet when you are not sure about the landing zone.

For example a small tree root would be catastrophic if you are landing with both wheel. What happens is that since the downwards force from the fall is applied to both wheels, it is much harder to roll over the obstacle. If the front wheel cannot roll over, you basically flipped.

But it is ok for the rear wheel to struggle to roll over an obstacle, as you can always drop the front wheel, balance the weight and roll easily over.
After the initial landing, there is always a bounce-back where all the tyre and spokes compression/tension is released.

It is better not to lose traction on the front wheel upon landing and thus landing on both wheel is also not a good idea.

What actually happens is 1) they are not exactly landing on rear wheel, it is an initial touch-down to reduce the falling momentum, 2) the body still continue to fall but decelerates thanks to the rear, 3) critical step to distribute the remaining falling momentum onto two wheels: too much on rear you will break something (minor) or even worse it will pump all your weight to the front wheel (see video at 34:54), too much on the front you will either flip or lose traction as previously discussed.

Having said all the above, what is important, perhaps a lot more important than whether you land on rear first or front first or both at the same time, is that you can extend the duration of impact as much as possible. This reduce the bounce-back as discussed in 2. Landing rear first is one way to prolong the impact and is also safer than landing front first.


Good resources to learn about forks Quick question. I have a lower quality mountain bike with a bad suspension fork. Overall the bike isn't bad. It fits me well and I have a lot of fun on it. I would like splurge on a new mountain bike but that just isn't a priority right now (but a cross bike would be pretty nice...).

So I was thinking that maybe what I should do is look around for a new fork. My general bike knowledge is pretty good but I know almost nothing about forks. I was hoping that someone could point me to a good reference on what I need to know before I buy a fork.

I think that buying a new fork probably isn't a good deal. I think for that price I should just buy a new bike. I would ideally like to spend around $100 but I would spend up to $200.  I suspect that this puts me in the used fork category.

Key features I would like out of my new fork:

Cold weather riding: my fork currently goes stiff at 5C
Lighter
Better traction/handling
More fun
Other - I have never ridden a better fork so "other"

Links:

Picture of my current bike (for context)
Brief description of my bike
Link to same question on Reddit

The bad news

$200 won't get a new fork much better than the one you have now.

The good news

The second-hand market is full of a couple of year old forks that were originally twice that.

Do your research

Forks may look frighteningly full of tech, but they are designed to be serviced so the delicate parts are inside cartridges that can safely be removed.  So if you see a fork you like on eBay for example, go to the manufacturers website and look at the servicing instructions - it will make your second-hand fork feel new again and only for the cost of new seals and some fork fluid (~$30).

Play it safe

Stick to the 'big 3' manufacturers: Marzocchi, RockShox, and Fox.
Do not go beyond 4 years old.
Remember to ask the seller what length their steerer tube is, it's normally cut down to fit the bike - but if their headtube is significantly smaller than yours you may have not enough material for your stem to bite onto.
Ask the seller if there are any scratches/dents on the stanchions (the smooth poles the seals grip onto), if there are - DO NOT BUY!
Ask the seller if the forks creak, it generally means the bushes need replacing.  Although this isn't too difficult, it will add ~$30 onto the servicing cost.
Finally, read reviews on your chosen fork MTBR is a good place.  And once you have any specific questions, come back here and we can help.


Goofy bike lane configuration right-of-way I was riding down the bike lane when a car hit me from the side with it's side. I ended up being drug about 30" or so before she came to a stop. I dont know her side of the story yet because I have not seen the police report yet. But what I'm wondering is who was in the right.
  As you can see in my poorly illustrated picture, I was close to the point when the bike lane crosses a traffic lane when the collision occurred. I did not see the vehicle until it was inches from my handlebar until it was too late. And I am not certain if she was crossing into that lane at the time either. From a distance, you can see the bike lane does this transition but there is no warning sign posted.
  Is anyone at fault, or is it considered a no fault accident?
Thanks for any insight.

I would say she is at fault. Here is why:

Since she was driving a car and you were dragged for some distance after the collision it appears she was traveling at a higher speed and thus was from behind. The responsibility typically falls on the one from behind. Even if the contact wasn't on your rear it sounds a lot like rear-ender.
A bike lane is a lane of traffic and has the same rights as other forms of traffic. Yes, @Willeke is correct this is poor street design, but this is not your fault. You were traveling straight and the car was the one initiating a turn and it was her responsibility to pay attention necessary to complete that turn safely. Yes, perhaps you should of paid some attention too, I hate it, but I watch out constantly for cars doing bad things. Convincing others that those who done did the bad things are at fault will be the hard part, as there is a contention that bicycles are toys not destined for the roads. But, this is not what the law says. Please fight for your (and our) rights.
Harm done. Sadly the United States does seem to have law or the general mentality to structure things this way, but I think those wielding a deadly force (like a car) have a responsibility to those more vulnerable like pedestrians and those on bikes. You may be able to use this very valid point to garner some compassion, but your mileage may vary.

Good luck.


My rear wheel keeps getting side to side wobble issues. Can it be too much pannier weight? It's now already the second time that the rear wheel has issues with side to side wobble and I would like to understand why this is happening.

The first time I had a bike mechanic to tune the true the wheel spokes but then it happened again.

I am not 100% sure but I have the feeling that both times it happened on occasions where I was carrying around 10-12 kilos in a single pannier (on the left side).

Mine is a mountain bike with a rear fitted pannier rack which can support up to 25 Kg of weight.

I know that carrying over 10 kilos on just one side is not ideal, but when I do so is only for a very short distance.

Anyway, I was wondering if that could in any way cause problems to the wheel spokes?

If the rim is aluminum made, truing it after a serious bend can result in fatigue of the material leading to repeated subsequent failures.

I'd try a sturdier replacement wheel instead of repeatedly truing it, especially if it's a job you pay for and not doing it yourself.

If you are happy with the hub  you can keep it and get just a rim. The cost of building a wheel can be pretty high though, depending on where you live.

The weight of the pannier should not count too much, unless you are a heavy rider and the total weight on the bike is near the specced limit of the wheel. This is usually the case for low-weight, racing, higher-end wheels (some have a 80-120kg limit) or for cheapo wheels with no specs and poor materials used.

The unbalanced weight should also not account for the issues you are having, given the fact the bike should be able to resist great side forces when turning, especially at high speeds.


Ultegra FC-R8000 Right Crank Arm Creak I have a 2018 Trek Domane SL6 Disc that I've put ~2500km on. I purchased an R8000 dual Stages power meter (Left and Right units) and fitted it onto my bike (following all the steps outlined in the dealers manual, and on many youtube videos). I still have lots of life left in my chainrings, so I swapped put my old chainrings on my new right crankarm. Since then I have been getting a creak when I put a decent amount of power into the pedals. My troubleshooting steps have been as follows (with the creak remaining after each one but the last):

Checked the torque on the chainring bolts (installed to 14Nm)
Cleaned the hell out of the drivetrain re-lubed
Had the LBS replace the bottom bracket and re-install the cranks
Checked the torque on seatpost (and then cleaned the seatpost, re-applied friction paste, and re-torqued)
Checked the torque on the seatrails (and cleaned, applied a light grease between clamp and rails)
Removed the rear derailleur, regreased, and reinstalled.
Removed the pedals and tried riding with flat pedals.
Put the new chainrings on the power meter cranks (and then swapped back once it didn't help).
Put the old (non powermeter) left crankarm back on (with the power meter right crank arm).
Finally - I installed the old right crankarm with the old chainrings with the new left crankarm (with power) - and voila - no creak!

I then swapped the old chainrings back onto the new right crankarm and the creak returned.

Other than a manufacturing issue from Shimano, or a power meter installation issue from Stages - I can't imagine what the mechanism is that would cause a creak from a right crank arm (given the above steps).

Has anyone experienced an Ultegra R8000 right crankarm being the ultimate culprit of a creak?

It seems that after all was said and done - putting the new crankset on another bike showed that the creak followed the crankset. Thus, the issue was a poorly bonded/other issue with the right crankarm or power meter.

My stock PF90BB was a bit loose as well, so the Token BB mentioned above was another benefit (and better design IMO).


What are good bicycle review and comparison sites? I'm thinking of buying a new road bike on the new year but I'm unsure which model to go for.

Are there any websites that maintain comparisons of currently available models?

There's http://www.bikeradar.com/ which is linked to 4 magazines: Cycling Plus, Mountain Biking UK, Procycling and What Mountain Bike. As a result it carries various bike and gear reviews from the magazines as well as some which are only online (I think).

As all of the magazines are UK based the site obviously has a British bias.


Opposed cone chainless progressive 24 speed gearing system using belts, has it been tried? I am wondering why on bikes I don't see them using a pair of opposed ice cream cone shaped gears such that a fixed length belt can be moved on them to change the gear ratio.  It would be cool if somehow the teeth on them could be recessed temporarily (perhaps using a cable) so that the belt could slide freely over the cones, then when the cable is released, engage the cones again.  This design would not be for everyone as there would be an interruption in power transfer everytime you would shift, however the same is true on most motorcycles where you normally use the clutch to shift to another gear.

The opposed cones could each have a diameter range of 3:1 for a total gearing spread of 9:1 so that the overall gearing could go from underdrive 0.5 to an  overdrive of 4.5:1.  4.5:1 would be similar to 50 tooth chainring driving an 11 tooth cog.  0.5:1 would be like a 20 tooth chainring driving a 40 tooth cog.  That range should just about satisfy everyone.

So my question is has this been tried and if so, why don't I see it in current bikes?  Has it been tried and it failed or is too expensive?  I would think (and expect) that with today's technology, Engineers could make this concept work.  It is similar to a CVT except that there wouldn't be infinitely many gears since the belt will have some thickness.  The cones need not be perfect cones but could just be "ramped" for each discrete gear.  For example, the cones could have 24 regions where discrete gear ratios could be engaged.  The advantage here is a simple progressive 24 speed and the final drive (perhaps another belt) can be made perfectly aligned and without any tensioner.

Here is a pic of a CVT transmission but my concept is slightly different as previously explained.

Also, just to clarify, my design would be indexed for 24 discrete gears, so where the belt touches the cones would be flat, not slanted like in this picture.  It would be cones with 24 flat regions basically.

I think it would be so much fun to ride a bike like this cuz as you would shift, you would have to pull a lever (like squeezing the clutch lever on a motorcycle between shifts), so it would feel a little like riding a human powered motorcycle.  The fun factor would go way up and I would be willing to pay more money for it.

Also note that with 24 evenly spaced gears, the ratio between adjacent gears would be about 10% which is a nice spacing and a 9:1 overall spread would be super fun.

Here are the ratios.  Format is sequential gear #, gear ratio:

1, 0.50
  2, 0.55
  3, 0.61
  4, 0.67
  5, 0.73
  6, 0.81
  7, 0.89
  8, 0.98
  9, 1.07
 10, 1.18
 11, 1.30
 12, 1.43
 13, 1.57
 14, 1.73
 15, 1.90
 16, 2.10
 17, 2.31
 18, 2.54
 19, 2.79
 20, 3.07
 21, 3.38
 22, 3.72
 23, 4.09
 24, 4.50

If someone didn't want to shift all these gears, they could instead skip gears such as go from 7 to 9 to 11... thus making it a speed super wide ratio 12 speed (21% between gears).  That would be fun too.

The indexed shifter could have 2 rings, one coarse and one fine.  The course would index 2 gears at a time whereas fine would index each gear.

Someone please make this bike in my lifetime so I can try it out.  It would also be cool if different cones would be offered so people could fine tune their gears such as close ratio (4:1) vs. wide ratio (9:1).  On the 4:1 spread, the 24 gears could be equally spread at only 6.2% apart for very fine tuning of cadence but with a good 12.8% between "double shifts".

CVT transmissions using conical pulleys and a V-belt are common on mopeds, scooters, and very small engined cars. One of the advantages is in the name: a continuously variable transmission with literally an infinite combination of gear ratios.

Why wouldn't you want this on a bicycle? At least the system on mopeds uses centrifugal linkages to provide the "automatic" transmission and is quite heavy and requires a relatively high RPM (much faster than most bicyclists can spin their pedals).

Furthermore, there is quite a lot of slippage caused by the v-belt especially in low gears and thus a lot of transmission power loss. For mopeds, this is actually a positive as it acts as a limited slip clutch but most bicyclists would object.

The second part of your question asks why this couldn't be done with stepped-cones. As you can tell from your photo, this would be an incredibly wide transmission. Fine for a lathe or mill (or whatever object is in the photo) but totally unsuited for most bicycles.

tl;dr: Too heavy, too complex, and  too much power loss for bicycles.

Remember, people want their bicycles to be simple, lightweight, inexpensive, and reliable. You could get a higher efficiency, lighter system using a gates belt on a rohloff hub.


Bell that sits above trigger shifter? I'm looking for a bell that will sit above a trigger shifter on a flat bar bike.
Placement is a safety issue: in this location I can maintain hands on bars, brakes, shifters and warn pedestrians at the same time.
I've tried a bell that sits next to the shifter and I have to take my hand off the bar to reach it.
Attached are photos of the old bell that broke, showing the dimensions & placement that I'm looking for. Unfortunately I've been unable to find a replacement that fits. The bells that I've found don't have a ~1.5cm gap between the clamp and the body of the bell, and only have a couple of MM clearance.

On one of my bikes I've set things up so I can hold the bars, brake, and use the bell all at the same time. I did this by mounting the bell underneath the handlebar instead of on top, which gets a low one much closer to the grip.


Disc brake lost power Firstly I'd like to mention that I don't think this issue is related to contamination (at least from sprays etc) and I'm aware of the following 2 threads:

Disc brake stop working after wash,

How do I get my hydraulic disc brakes working well again

I'm having trouble with the rear brake on my mountain bike. It's running Shimano XT (BR-M8000). The braking power seems very feeble and I'm getting a squeal as the bike slows to near-stop.

So far I have tried cleaning throughly with alcohol, brake cleaner and even taken the rotors of and cleaned them with soapy water followed by isopropyl alcohol. I've keyed the pad with emery paper and even swapped the pads out.

I've bled the brake twice and the initial feeling through the lever is good. I did my best to get all the air out and extended the reach to get a greater pull on it.

I wondered whether I'd glazed the rotors and replaced them with brand new (and cleaned) rotors as I'd been meaning to do so for some time to reduce noise.

My new rotors a some Shimano Ice Tech 160mm centre-lock so should be the right gauge. I've bedded them in without dousing with water as some do. The front brake is a larger rotor but bites really well. I can't even skid the back wheel.

I don't think the calliper is leaking but I haven't done extensive checks to see. I did get what felt like a much better brake when I got them covered in sandy mud. After I cleaned the bike with muc-off the brake was back to being pants again.

My next steps were going to be to check the brake hose for weak spots and/or bulges. Replace the hose if needed.

Last option is to empty the system and clean the calliper and remove, clean and reseal the calliper pistons.

Is there anything else I can do before I go down these routes?

I also had noise and power issues with my m8000s when they were new.  Sanding the pads and cleaning the rotors made no difference.  My solution was to remove the pads, clamp them in a vise, and hit them with a propane torch for about 30 secs each.  They briefly flamed up, which to me indicated contamination.  Once reinstalled there was power and silence.  That was over a year ago and the problem has not returned.

There is a good thread on MTBR about this issue.

http://forums.mtbr.com/brake-time/xt-xtr-brakes-get-squeal-power-loss-after-sitting-idle-6-8-weeks-902792.html


Please help Identify Italian frame 59-60cm frame, Sun Tour Superbe Pro Brakes, Shifter, front and rear derailleur, and complete Crank is Sun Tour Superbe Pro. Campagnolo head set and pedals. Cinelli 64-40 handle bar and Cinelli stem. It's an Italian make I'm sure. Serial number on the BB is BMZ 09 is all I can make out. Any help is greatly appreciated!

BMZ presumably stands for Biemmezeta, an Italian manufacturer from near Milan who did a lot of contract manufacturing for a lot of places (e.g. Performance Cycles) as well as sold bicycles under their own brand. More details on your location may help narrow down the bike's pedigree.

As Daniel R Hicks estimates the date of the bike in the comments, it should be noted that BMZ was popular in the 1980s.


What factors influence how easy it is to track-stand a bike? What are the characteristics of a bike that make it easy or hard to track stand on?

I have tried track standing on multiple different bikes and they are all dramatically different in terms of how easy it is to track stand on them.

2016 Gravel Bike (somewhere between a cross bike and a touring bike) - It is very easy to track stand
1990s era mountain bike with rigid fork - The bike is a bit small for me and reasonably easy to track stand
1980s era road bike - Hard to track stand on
2010 low-end mountain bike - Hard to track stand on

The interplay between Head Angle and fork rake and trail are biggest factors influencing (low speed/no speed) bicycle handling.    Steep head angles and shallow trail values result in an increased sensitivity (more Twitchy) feels to steering input.

I would argue that these factors are factors that describe the handling responsiveness of a bike and not its track standing ability.... as what works for one person in a track stand may not be the preference of another....

Secondary contributors are bottom bracket height which will affect center of gravity, wheelbase length and chain stay length which effect stability.

Learning about these frame attributes and what works for you in which situation will not only help you identify what enables your track stand but also help in making informed frame selections by looking at spec sheets.

Finally, looking at your list, if I where to generalize without knowing the detailed specs... it seems you can track stand on bikes with shallow head angles with longer wheel bases/chain stay lengths.


How to remove the broken ball end of a small hex key that is now stuck inside the socket While trying to replace the yoke of my derailleur I made the mistake of using a multi-tool hex key that was not able to handle the torque necessary for the task and snapped while the head stayed inside.
I tried using gravity, a magnet, shaking and all combined to make the head fall down, to no avail. I've no idea on how to proceed further and am really thinking of getting a new derailleur.

Chances are you were turning it clockwise when it broke. By tapping it anti-clockwise with a small drift or cold chisel, it may unjam it, when a magnet along with gravity and tapping should release it.


Chain lube clean like wax but last like oil? Is there a lube that is as clean as Wax but last like oil?

A bit of context, I ride a mountain bike in norcal, normally I use wax for all my bikes, I've been doing it for years.
I do hot laps (7 miles) like 4 times on work days and then weekend rides(2x15 miles~), every two rides or so, my chain will be dry, so I rewax it.
I clean the chain twice a week on Fridays and Mondays. I do so by taking my park tools chain cleaner, fill it up with rubbing alcohol and clean the chain, then carefully re-wax and wipe off the excess.

I love how easy is to clean wax, I also love how clean is, dirt doesn't stick to it BUT I HATE having to clean-rewax so often. I've gone through several oil based lubes with nasty results, lots of gunk everywhere, I know dry lube is supposed to be cleaner than wet but it still nasty for me, or I've tried the wrong ones.

From a practice perspective, what kinds of lube do you guys use? I just want to spend less time cleaning and more riding...

From a practice perspective, what kinds of lube do you guys use? I
  just want to spend less time cleaning and more riding...

I DO NOT RECOMMEND PRODUCTS BELOW, JUST AN ANSWER TO THE QUESTION.

I use squirt dry lube. your chain stays very clean and it's long lasting in good weather conditions. if it does rain or in winter squirt has a low-temp dry lube for cold & wet conditions.


Freehub body wiggles This is a OEM wheel from a 2014 Salsa El Mariachi Single Speed, called a "Salsa 2, Singlespeed" hub, which I believe is made by Formula. The freehub body "wiggles" (the thing that my fingers are touching in the photos). I tried to show the wiggle in the last two photos, but it may not be perceptible in the photos; it moves by about 1mm. Do I need a whole new freehub body? If so, how can I find a replacement? Or do I just need to service the one I have? Or lord please don't tell me I need a whole new wheel!

You don't say what brand of hub it is so I'm assuming it's a could-be-anything OEM singlespeed MTB cassette hub.

There is no universal answer. If you want to figure it out yourself and you have no other real information about the hub (which would usually be the case unless it's from an aftermarket hub maker), you have to take it all the way apart and see what there is to see. Some hubs, for example most Shimano cassette hubs, can be tuned for freehub play by permanently removing one of a set of very thin shims inside that are there just for that purpose, but one has to take the unusual step of completely disassembling the freehub body. It's also possible that play is occuring because a freehub cartridge bearing is destroyed, in which case can just replace the bearing.

Depending on the design of the hub, it's possible that this could be a simple adjustment, but that's not usually the case.

If you do find that you need a replacement freehub body, and it is an OEM wheel, they can be tricky to get hold of but it's possible more often than some might have you think. If it's branded by a bike company then the first place to start is a call to that company's warranty department, which in some cases might just have it laying around, especially if you know the exact model and year of the bike. If that doesn't get you anywhere, which is entirely possible, then it becomes a matter of pouring through images of all the Novatec, Formula, KT, King Kong/KK, Chosen, etc hubs of that genre that have ever been made, getting the model, and making contact with a representative of that company that speaks your language. At that point arrangements can often be made to get hold of a replacement freehub body. Since this is a singlespeed it's probably more of a longshot than usual that this plan will work, but it's worth trying.


Do silent freewheels exist? I have only just noticed that my bike dosen't seem to make a lot of noise when free wheeling, in fact it's pretty much silent. Is this down to the fact that I have been putting off a major clean?, is my bike damaged? or is my bike equipped with a silent freewheel that I didn't know existed?

I am currently riding a Scott Aspect 30 Mountain Bike

Your hub has a normal freewheel, like described by Matt Adams (ratchet with pawls).

There are some models which have spring-loaded cylinders mounted around "tilted" teeth: when you spin it to one side, the cylinders slip. When you spin it to the other side, the cylinders are caught between opposite surfaces, and torque is transmitted by friction (there is no positive engagement between parts).

Lots of backpedal-brake rear-hubs have this system.

Shimano had a Deore LX named "Silent Clutch" with this mechanism, but it was heavy.

Also, I know at least one model (American Classic) which instead of the spring to load the pawls, have a rotary disc to engage and disengage the pawl, and a tiny hair-sized spring which act as the freewheel for this plate. It is a very silent and low-friction system:


Caliper road brakes on cantilever specific frame I just bought a used bike with cantilever brakes that are very stiff (it's quite hard to push them) and weak. I have been fiddling with them for about two weeks now but to no avail (only the smallest improvement). Since I plan to use the bike for road only (it's originally a cross bike) I tought I would just switch the brakes to caliper ones and be done with it. The problem is that there are no caliper mounting holes only the canti ones.
I'm also kinda hesitant to buy new canti brakes because I don't want to waste my money and then find out the new brakes act the same way the old ones did.

My question is: Is it possible to install some kind of adapter/bridge on the cantilever mounting points so that I could install caliper brakes on it?

Also if you have any other ideas I would appreciate them greatly.

Thanks!

EDIT:
Here are the pictures I promissed, the front and rear brakes are basically identical, only difference us that the rear ones have longer brake pads.

I also forgot to mention that the spring is in the lowest hole so it should be really easy to push the levers.

Typically arms are more up.  Up arms should give you a little better leverage.

Sheldon geometry of cantilever brakes

If the pads are hard then new soft pads will help.

With cantilever you would have the option of running larger touring tires in the future.


Modify M6000 brake caliper? I am attempting to fit Shimano Deore M6000 brakes to my 2017 Trek Stache. The rear brake contacts the frame near the bleed port and keeps me from being able to fully align the caliper to the disk.

The caliper is really close to having enough play in it to get aligned to the rotor. Can I file about 1 to 1.5mm off of the caliper body right where its contacting the frame?

I know there are other brakes I could buy which would clear the frame. For reference the bike came with Tektro M285 calipers which had plenty of space. I've done my research about what other brakes can fit, but I like the M6000 levers compared to others in my price range.

I though about it long and hard and consulted a friend who works for yeti in manufacturing. Figured there is some margin for manufacturing tolerance and factor of safety.

Filing worked like a charm. Wet sanded and polished the cut afterwards and it looks great. I figured the only real worry at that spot on the caliper is structural support in case of a crash, but its protected behind the seat stay, so a little less is probably not an issue. Besides, this is the kind of material removal that might happen in a crash.

Cleaned it all up with isopropyl alcohol, toothbrush, and compressed air afterwards.

I may put some color match paint on there at some point.

Doing this was ultimately up to me and to the average person I wouldn't recommend this, but I knew I could do it well so I went for it.


Could a flat tyre two days later be due to a clumsy service? I had my bike serviced on Monday. Part way through the workshop called to inform me that they thought both tyres were perished and needed replacing. I trusted their judgement and gave them the go ahead.

It was fine on Tuesday and Wednesday. Today - Thursday - I got it out this morning and discovered the front tyre was flat. I re-inflated it and rode to work and it seemed fine. But it was completely flat again by lunchtime, so it's a slow puncture.

I haven't ridden any out of the ordinary routes, nor am I aware of having ridden over anything that would cause a puncture. So, obviously, I'm now wondering if the service might have had something to do with this.

I don't want to take it back to the workshop and start throwing accusations around without some evidence. So is this likely just coincidence? Or, if there's a significant chance they might have damaged the tube while replacing the tyres, is there anything I can do to prove it?

To me, this sounds like coincidence. If the shop had punctured the tube and caused a leak, I don't think it would have held air for two days before showing any signs of going flat. Especially given the fact that you reinflated the tube and it went flat again by lunchtime. The leak is fast enough to make the tube go flat in just a few hours, so it seems unlikely that the tube would be OK for Tuesday and Wednesday and only start leaking on Thursday. When replacing the tube, you should look for the cause of the leak. You might be able to find a foreign object that caused it, but it's possible you won't with a typical puncture. If you find the side of the tube leaking, that might indicate that it got pinched by the tire during installation


What bolt size are Shimano brake caliper bolts? A front caliper bolt on a shimano disc brake caliper came out while riding, and went lost, while the remaining bolt, which was a little bit longer and thus protruded a little was completely bent.
Attempts to fix: went looking for matching bolts at hardware stores, by using rear caliper bolt for measurement (couldn't find any).
Questions: Given one bolt bent while still seated in the fork's caliper holder, should i try new bolts, or focus on a new brake caliper, or, is the fork most likely damaged, where would i go from here; new bolts, caliper or fork? And if bolts, at least one lbs didn't have em either.

On the approximately 5 different models of Shimano disc brakes I've dealt with over the years, the caliper fixing bolts are M6 x 18.7mm, and they are socket head cap screws in non- bicycle parlance. This length of fixing bolt would be if you were using 160mm rotors in a post mount set-up.  For systems using 180 or 203mm rotors, you'll need about 40mm of length on your caliper fixing bolts to get thru the caliper and the associated adapter.
At farm, home, or hardware stores in their bolt bins you will find in their metric section, "socket head cap" screws (they will have the blunt end like a bolt, but they are screws because they are used by screwing them into existing threads, not with an associated nut.  That's then a bolt.) The closest length you'll get is 20mm, though some places may have 18mm M6 socket heads in stock. They'll also have 30 and 40mm lengths typically.
While you're there, purchase some blue Loctite 242 (aka, threadlocker blue) and follow the instructions for that using it on the caliper fixing bolts (well, they're screws, but Shimano calls em bolts) when you go to mount your caliper.  And tighten to the recommended torque value range of 6-8 Newton-meters (50-73 inch-pounds).
Properly torqued fasteners with threadlocker will not "come loose" without mechanically assisted human effort.  It's still a good idea to check the fastness of your calipers before every ride and recheck with a torque wrench every so often, especially after the first ride or two after install.


Proper dedicated ebike frame with motor in the middle or the diy swap the wheel approach I'm interested in converting my carpe 40 into an electric bike.

I was wondering what are the pros and cons between having a dedicated ebike frame vs a DIY approach that involves a new front or rear wheel.

My current bike's rear hub has a modern freehub body with a cassette and not a freewheel.

You're asking two distinct questions here.

1) DIY vs Store Bought.

Do a DIY if you're mechanically inclined and will enjoy the project as hobby time.
Do a DIY if you have some classic frame you love.
Do a DIY if you want an off-road only high powered beast of a bike.

There are certainly some very cheap kits going around on Amazon etc.  I would be very dubious of a deal where you appear to get an entire eBike conversion kit for hardly more than what would be the wholesale cost of just the raw battery cells if it were a name-brand battery!  (also remember to add all the tools you're going to need to the apparent cost if you don't already have a kitted bike shop.)

Buy it at a store (from an actual bike shop that also services that brand of motor)  if you just want a street legal bike to get around town.

2) mid-drive vs hub-drive holy war very high level generalizations (I own both don't flame me) (yes some of these are not actually about the drive methodology but what's commonly available in which form from stores vs online etc.  they're generalizations)

Mid-drive Pros

motor torque is going through your drive train so gearing can amplify it for demanding climbs
major retail brands have torque sensors in the crank, results in much more natural "bike that helps me out" feel when riding.
the major brands have large dealer networks that can service them

Mid-drive Cons

some designs may have more failure modes where you can't pedal home if the motor breaks
motor torque is going through your drive train, may wear out drive trains faster

Geared Hub-drive Pros

simpler and cheaper, if it does break just the motor is not $$$ to replace
anecdotally much less likely to break in the first place.  Don't know of actual data specifically for bikes. (The fundamental motor design is simple and well proven.  Some mid-drive designs are very complicated with lots of gearing)
Throttle is more readily available if legal and you care for it (although there are more mid-drive bikes with throttles lately.)

Geared Hub-drive Cons

less expensive models don't have torque sensors, only cadence
sensors.  Results in a bike that can feel "pushy" and less natural.
I've ridden some that basically feel like an electric dirt bike that
happens to have pedals on it.  (Maybe that's your preference and this
isn't a Con :) )
on-line only retailers may end up with you waiting
for weeks for service or needing to know how to thread your own
wheels to replace a motor.

Direct Hub-drive

No


Most effective pedal position to jump start from still situation All other conditions (strenght, gear, etc.) being the same, what is the most efficient position of the pedals when starting from a still situation on a very short sprint (like crossing 10 meters wide road with a traffic light giving the start)?

I.e. I think that with the pedal on the highest point one can continuosly push for 180 degrees, but will start with a low torque, while with the pedal being horizontal one will start with the max torque but will then continue with reducing torque on just 90 degrees.

When you are starting, most force comes from your weight on the front pedal. The highest leverage is available when the pedal is in the 3 o'clock position. But starting there would waste the (potential) energy from going from the 12 o'clock (no leverage but maximal potential energy) to the 3 o'clock position. Hence, it makes a lot of sense starting with pedals in the 1 o'clock position with leverage increasing towards 3 o'clock and decreasing towards 6 o'clock.

A physics student could come up with an analysis for the best starting point by also taking into account the inertia of the system but I can't and have to leave it to may hand-waving arguments above.


I'd like to be able to climb hills better: is it an option to increase the diameters of the largest gears on rear cassette? I'm a beginner cyclist and I'd like to be able to climb hills better.
Of course there are many approaches to this, including fitness and technique. I am trying those, but on top of that, I'm thinking of 'hardware' options.
But I'd like to keep costs low if possible. One way I was thinking of is to buy a rear cassette that maintains the same width (in my case six-speed - as I want to keep the same bike frame), but increase the diameters of the largest gears. Is this possible?
The largest gear on my present cassette is 8.7cm. It is a freewheel if I'm not mistaken.
(photos included in case this helps)

Gears are measured in terms of the number of teeth, not the width.
The mechanical advantage is given by the number of teeth on the front chainring divided by the number of teeth at the back.
Often this is then multiplied by the diameter of the tyre, to give a measurement in 'gear inches'.
Your bike looks to have a 14t-28t freewheel. Your rear derailleur is a 'mid cage' model designed for 14-28t freewheel and a 20t front difference, for example a 48-38-28 or a 44-34-24 triple chainset.
You might be able to change the freewheel for a 14t-34t six-speed freewheel, but if you have a triple chainset fitted, then your mid cage derailleur may be beyond its limits. In this case a similar quality 'Tourney' SGS (long cage) derailleur should be quite cheap to buy if it does not work well.
As you have not indicated whether you have a triple, double chainset or a single chainring at front, it's hard to say the main cause of your trouble - for example if you have just one chainring up front, then the 28t small cog is likely to result in a very hard easiest gear, and in that case the problem is at the front, not the back.
However it is quite possible that you do have for example a 48-38-28 chainset with the 14-28 freewheel, which is not a particularly hard gear compared to a modern racing bicycle sold for non-athletes, which will typically have a 50-34t chainset with an 11-34t cog (28/28 is the same gear ratio as 34.34), but your bike is likely to be heavier, so this still might not be enough.
Anyway, switching from 14-28t to 14-34t or 13t-34t freewheel will give you a considerably easier gear, but you might end up needing a new rear derailleur as well, and it would be easier to answer your question knowing about your front chainring(s).


Where should I mount a mirror? What do you recommend as an optimal point and orientation for mounting a rear-view mirror? I'm open to handlebar-, glasses-, or helmet-mounted.

Some of the considerations, as I understand it, are:

Ease of mounting.
View provided.
Vibration.
Likelihood of breaking.
Robustness for repeated off and on (for glasses-mounted).

I've got a hybrid bike with flat handlebars.

I'd also welcome specific product recommendations and recommendations about other aspects to look for in a mirror.

A mirror is a great addition to a cyclist's toolkit. While all cyclists should be able to look around behind them without one, a mirror lets you do this more often and safely. And a mirror is no substitute for looking behind you anyway. Here's a summary of the kinds of mirrors I've used.

Glasses-mounted mirrors like the take-a-look mirror are great for giving you a wide, easily adjustable field of view. Pivoting your head means you can "sweep" the area behind you, and the mirror is close to your eye so it's a fairly wide field of view. However, they're only usable if you wear glasses or goggles, and some mirrors won't mount to some glasses, particularly glasses with thicker temples like some non-prescription sunglasses.

I find that the take-a-look is a great mirror, but it tends to pull my glasses off just a bit over time. Adjusting it is merely an annoyance that I've decided to live with, since the mirror is otherwise excellent. (My glasses are also extremely light, and this would happen with any mirror, although the take-a-look is fairly heavy for a mirror.)

Upside: Great field of view, keeps the mirror off the bike. Inexpensive.
Downside: A little more finicky to adjust than bar-mounted mirrors, easy to forget.

If you don't wear glasses, or prefer not to put a mirror there, you can get a helmet-mounted mirror instead. Most of these attach to your helmet with adhesive pads. The only one I've had that I cared for attached to a helmet's visor that was designed to accept it. Look at helmets specifically for commuters if you want one of these, I loved it but had to get rid of it when I replaced the helmet.

Upside: The mirror is always there.
Downsides: More vibration, smaller mirror, and you're locked into that helmet if you want to keep the mirror. Harder to adjust than any other kind of mirror, since your head is always moving and your helmet moves a bit on your head - unless your helmet is really tight.

Handlebar-mounted mirrors are generally larger in area and have a curved surface. (Think "objects in mirror are closet than they appear".) The ones meant for drop bars usually mount with velcro or another attachment system, and the ones for flat bars will generally be screwed onto the side of the bars. I've never found one I liked for drop bars, but the flat-bar mirrors work quite well.

Upside: The mirror is always there, and the permanently mounted ones are easier to adjust than any other system.
Downside: A little clunky, they make your bike wider (an issue if you need to take your bike on the train or if you have a folding bike), and you need to look down to see it, taking your eyes off the road. Can be snapped off if the bike falls or grazes a wall. (Some are advertised as "folding on impact", though.)

Recommendations

Outside of the ubiquitous take-a-look mirror, it's difficult to give specific product recommendations. But there are only a few kinds of mirror available, and even the most expensive mirrors are still fairy cheap.

I'd avoid plastic eyeglass-mounted mirrors, as they tend to break. But a good eyeglass mirror will give you the best rear visibility.

If you want to avoid eyeglass mirrors: In your situation, with flat bars, I recommend a mirror that screws into the sides of the bars. You can put on one or two mirrors, depending on your situation. For example, in countries where you ride on the right, a single mirror on the left side of your bar will cover almost all situations. Having a second one on the right is nice, as it covers your "blind spot", I consider it a luxury.

In the end, everybody has different preferences with mirrors. You really need to try a few different kinds and brands and see what you prefer. There is a silver lining, though; many cyclists have unused mirrors. Chat up some cyclists if you have a club or friends who cycle, and someone will likely offer to lend you a mirror of give it to you outright.


Does more gear inches on a folding bikes work better? Below are technical details of 2 folding bike that I am considering.

Friends, can I safely assume that the option 2 with more gear inches would be a good choice. I am a recreational weekend rider. I am gonna ride this for not more than 30 minutes on comparatively flat paved suburban roads with slight hills. I do not fancy fast but yes I would like to tackle some ascend and descend comfortably.

Is there a bigger question technically related to gears that I am missing?

Option 1

Gearing  14-28T 6-speed freewheel.
Chainwheel 52T steel chainwheel with 170mm alloy crank arms.
ChainRing Teeth : 52
Rear Sprocket Teeth: 14,16,18,21,24,28
Gear inches  69, 60, 54, 46, 40, 35
6 Speed Shimano drivetrain

Option 2

48T steel chainwheel with 170mm alloy crank arms.
ChainRing Teeth : 48
Rear Sprocket Teeth : 14,16,18,20,22,24,34
Gear inches  64, 56, 49.8, 44.8, 40.8, 37.4, 26.4
7 Speed Shimano drivetrain

Thanks

"Gear inches" is a way to define how "difficult" a given gear is.  A larger value means that the gear is more "difficult" and will take more leg muscle to move the bike forward.  A smaller value means that the gear is "easier" and hence you'll be able to climb steeper hills.

We can't tell you what range of values is right for you.  Your option 2 above has 7 different combos, vs 6 for option 1, and the "smallest" gear is smaller (in gear inches), meaning it will be "easier" than the "smallest" gear for option 1.  The "largest" gear for option 2 is also smaller than the "largest" for option 1, meaning that you will not be able to go as fast on flat land or going downhill.

But none of this really has anything to do with the bike being a folder, other than the fact that folders typically have a more limited gear range.


How do I wrap a road bike handlebar? What is the best way to wrap a handlebar?

Specifically:

Should I start near the stem or at the bar ends?
wrap clockwise or counter-clockwise?
How to wrap (e.g. how many times) around where the brake hoods are?

Park Tools has a great description with a video, pictures, and instructions.

Expanding the Park link a little:

1 - you can start at either end, conventionally start at the bar ends because that way the overlap on the wraps has the lower side out so smooths as you slide your hands down the bar. That way it lasts longer and looks nicer.

2 - wrap up the outside on both sides. So the answer to your question is "yes".

3 - this is where most of the variation in styling occurs. Tape that is more flexible or stretchy can have fewer wraps around the brake levers, although you can often do a single skip around the back of the lever even with quite unyeilding tape. I prefer to go once around the levers to get 3 strips of tape behind them. Experiment to see what works for you.

If you're wrapping bars for the first time I suggest buying the cheapest tape you can find to experiment with, as well as the stuff you actually want. It's something that's not too hard but you will probably make mistakes the first time.


Internal Cabling Problem? I've been having some bike issues with a 2016 Trek Allant 7.4 . I'm looking for any documentation about this problem, or any known solutions that don't include externally routing the cable.

Long story short is that the gears aren't shifting properly. I've seen it up on the mechanic's stand and within a few minutes he was able to downshift on the shifter and the derailleur didn't budge at all.

When I ride you have to downshift one past the gear you want and then upshift again to reliably get it into gear.

If you downshift a few gears at once, like you might when going up a hill, downshifting one more than you need and then up again doesn't always seem to get you into the gear that's selected on the shifter.

What happens then is that the derailleur changes the gears at some unexpected time to the gear that is actually selected on the shifter. There's a crunch that I'm sure isn't great for the cassette or the chain, and your weight gets thrown off balance.

The mechanic I spoke to said that this was a problem with the design of the Allant 7.4. The shifter cable comes out straight at the same angle from the chain stay. It gets bent upward and sits in contact with the quick release nut. The mechanic told me that the problem was due to the sharpness of the angle that the cable was routed after it exited the chain stay.

The same mechanic told me that this problem was addressed in later models. I've attached a photo of the Allant 7.4 and FX-4 routing and you can see that the FX-4 angles the cable upward at the exit from the chain stay. It looks like the FX-4 routing is along a much more gentle curve as well.

The shop I bought the bike from has replaced every single component involved in the rear gears (possibly not the external sheath at the back? The manager told me this couldn't be the cause of the problem). The cassette, derailleur, chain, shifters, shifter cable core (now using a thinner core) have all been replaced.

The bike has been looked at by 5 mechanics: 3 mechanics from the store that retailed the bike and stock only Trek bicycles, and 2 mechanics who are Trek employees.

This experience has really put me off internally routed cabling and Trek bikes in general to be completely honest.

Does anyone know of any documentation around this issue? Are there any known fixes?

https://archive.trekbikes.com/au/en/2016/Trek/allant_7_4#/au/en/2016/Trek/allant_7_4/details

https://www.trekbikes.com/au/en_AU/bikes/hybrid-bikes/fitness-bikes/fx/fx-sport-4/p/21559/?colorCode=grey

The cable doesn't flare out to the right that much, I think my phone's camera is giving a bit of a fisheye effect up this close.

I agree with Nathan Knutson's comment that this looks like cable friction, but I suspect confirmation bias has everyone looking at the wrong portion of the cable routing.

  The mechanic I spoke to said that this was a problem with the design of the Allant 7.4. The shifter cable comes out straight at the same angle from the chain stay. It gets bent upward and sits in contact with the quick release nut. The mechanic told me that the problem was due to the sharpness of the angle that the cable was routed after it exited the chain stay.

The rear derailleur cable routing isn't perfect, but it does not look that bad either. There is nothing inherently wrong with the cable housing touching something.  The problem can arise if the housing is severely kinked, which doesn't appear to be the case, I beleive the manager is correct in that this is likely not the culprit.

You also said:

  The shop I bought the bike from has replaced every single component involved in the rear gears (possibly not the external sheath at the back? The manager told me this couldn't be the cause of the problem). The cassette, derailleur, chain, shifters, shifter cable core (now using a thinner core) have all been replaced.

This still leaves a couple possibilities:

Cable housing from the shifter to the frame has a kink.  You made no mention of whether or not the cable housing (cable outer) was changed.  If the housing is a bit short and/or the handle bars get over rotated this can damage the housing.  This however should have been obvious from inspection, and I would hope a reputable shop would have looked here first, long before cassettes, derailleurs and shifters!
Inside the frame, you are missing a sheath or the cables inadvertently became entangled during assembly. If the cables are tangled, then this would cause extra friction. You might be able to see this by activating one shifter and looking for movement on the other derailleur. Friction could also be increased if an internal sheath is missing. Most internally routed systems will run the cable inside a sheath to reduce friction. If is missing, then the friction is higher.
The shop changed the inner cable, but depending on how this was done, they might have missed these type of problem (e.g., you pull the new inner cable through by using cable that is currently in place).

Typically, internal cable routing results in straighter cable runs and should provide better shifting for longer than external routing.


Air Pressure on wheels Does the perfect air pressure is related to the performance of bikes? If yes, what is the exact amount of pressure required on MTB, Hybrid, City Bikes and BMX?

The optimum pressure for any kind of bike is going to depend on a lot more factors than just the type of bike. You have to look at many other things such as rider weight, terrain, and tire size. It also depends on how you qualify something as optimum. Higher pressures might be optimum in some situations, but may not be very comfortable to the rider, making long rides very hard on their body.


Bridgeless suspension forks Suspension forks typically have a bridge which connects the two lower legs. In the past, this also provided a hanger for the rim brakes. I always thought though that the main purpose was to ensure that the two legs remained parallel in compression, so that there was no torsion on the front axle.

I've noticed some MTB suspension forks that are bridgeless. In these systems what prevents the legs from compressing at different rates and twisting the axle? Can we broadly say a bridgeless suspension is weaker than a bridged one?

No, you can't broadly say "Bridged suspensions are stronger".  It's depends on many things, including the design of the system, materials used, build quality, etc.

As Batman mentioned, Cannondale's Lefty suspension is stronger than most traditional systems and isn't bridged, or even bridgeable.

Inverted, or "upside-down" systems, like the one in your photo, have other considerations as well, outlined in this question.  To your question, the thru axel keeps the stanchions bound together, preventing different rates of compression.

I think we will see fewer front forks with suspension bridges in the future and more inverted systems, as the technology trickles out to less expensive builds and the cost of manufacture drops.


Adding lower gears to a nine speed Ultegra road bike with triple ring My wife has a road bike with an Ultegra triple crank and a nine speed Ultegra 13/30 cassette. She needs a lower gear. Can the derailleur handle a larger rear sprocket? Ho large?

I’m not sure which version of an Ultegra derailleur you’ve got, but if it’s the 6500, it’s only rated for a 27-tooth cog and 37 teeth of wrap. You’re probably at 31 teeth of wrap.

It might be more productive to put on smaller chainrings. Depending on what she’s got now, that’ll get her an extra gear or two.


Specialized Rock Hopper (1987) - Service I was wondering if anyone might have a service manual of some description for a vintage Specialized Rock Hopper(1987 - Yellow)?

I have googled this for hours and hours and have tried contacting Specialized directly but no dice. I need to find out how to remove the rear brake, there appears to be something (perhaps a hidden pin) holding it to the bike. I really need to find out how to remove this, and I really don't want to pay the LBS for what could be a simple fix (colour me stingy).

As you can see, I've got a lot of work ahead of me to make this bike cosmetically sound, but the brakes are the only mechanical failing... Ideally I'd like to take them off to give them a deep clean, and to lubricate each part.

Any help would be greatly appreciated.

Many thanks,
Bill

These are just old U-Brakes (installed at the chain stays as was cool for part of the late 80s). You just need to unbolt them from the studs (maybe hit it with some penetrating oil to help loosen it oFF the studs). Unfortunately due to the placement of the U brake , you're going to need to get another u brake since you won't be able to mount a normal brake that way.


What should my first adult bike have? I bike a lot and I'm looking to spend £400-800 on a full size bike. It must have full suspension, detachable front wheel, preferably room for a minipump and a large water bottle (without using the far bottom side of the frame). I see this is close to a discussion, but I think there are some obvious answers I'm overlooking. Bike or shop suggestions welcome.

Update: I commute (half off-road), use the canals, in-town and between-town roads, and a lot of off-roading. I would like to be able to manage my bike well, hopefully learn to do more than just replace tyres/tubes. It will occasionally be carried by car. I use bike lanes, pavements and the middle of the road fairly equally.

How complex are softer drivetrains and disc brakes? I'm not familiar with either of them.

£ so if you are in the UK, check out Edinburgh bike coop if there's one near you.

Definitely get disc brakes. Opinions on full suspension bikes differ - it used to be said that if your are spending less than $1000 don't get it. But I don't do extreme downhill so don't really know.

Most mountain bikers use camelbacks rather than water bottles because off road the bottles get covered in dirt (=cow shit) and you catch lurgy and die.  You can always add a water bottle holder later.


Why and how much is riding big-chainring-frong small-cog-rear a negative practice? A friend of mine is riding consistently in largest chainring front and smallest cog rear. The corresponding teeth counts are respectively 44 and 11.

The bicycle is an Acera-level mountain bike with very light and fitting them frame. Gears shift relatively quickly and reliably.

Their average speed is about 30km/h, while commuting 20km total per day. The traffic is average.

Their acceleration at traffic light is low. However, I have observed no other drawbacks. To my surprise, the chain and smallest cog are still operational, after 1-2 years of year-round commuting - dust, snow, salt, mud, rain. (measured with a chain ruler)

Also, when it becomes impossible to ride this gear (standing up), they switch to a much much easier gear.

Is this a reason for concern? Knees, traffic safety, mountain trekking endurance, bike components wear (from most important to least important)?

EDIT:
A couple of clarifications:

The tires are 26x2.0 semi-slicks.
It was a mistake to claim average speed of 30km/h. This is rather cruising speed. On the other hand, starting from a red light or recovering from a difficult turn takes forever (5 seconds for example).

As commented by @Daniel R Hicks the problems I would be concerned about are to his own health. The bike components that will wear out prematurely are simpler to replace.

Potential health issues are knee problems from "mushing" all the time. MTBer's tend to run lower cadence than road riders, for valid reasons, but when on the road tend to run closer to road cadence. Mushing causes excessive pressure on the knee, causing the joint to wear out - its an Orthopedic surgeons retirement plan, in 20 years time he will be doing knee replacements.

The other concern is mixing it with traffic in high gear. You have limited ability to accelerate and your balance is often compromised. Under usual conditions, not a problem, but in an emergency that could be the difference between a close call and a grease mark on the road.

Less of a concern, and people physical attributes vary, is endurance and aerobic capacity. The reason for spinning faster is it provides maximum aerobic efficiency. Under about 80RPM you are not able to maximize the power output of you legs. Beginners often spin too slow, as the optimal cadence needs technique and practice to learn how.  To some it feels you are going faster mushing as it feels like it takes less effort if you spin faster. I find a good test is to get them to change down a gear, keep the same effort and monitor their speed. Most are surprised to see an instant increase of 1 or 2km/h for no more effort.

If you are really keen to get him to spin faster, put him on a bike with short - really short (like 145mm off a kids bike)- cranks for a few rides. As you have much lower torque, you have to spin to go fast, but spinning smoothly is easier, so you just do it. It's a great training aid.


Reynolds 531 frame single speed Very newbie question and possibly obvious. I've been looking at purchasing a Reynolds 531 (frame only) to create a single speed bike. Are the brakes, wheels, gearing etc universal among all 531 frames?

No. 531 is a frame material from which any type of bike can be built. It's actually Reynolds 531 a brand name, from which different tubesets are made and they have also sold small quantities of raw tubing as well as custom butted tubes. That exact tubing is now somewhat dated, they sell newer compositions with different numbers now.

So all you can really say about a bike with 531 tubing is that it's probably more than 5 years old. It might be a touring bike, it might even be a load bike, but more likely it's a road or track racing bike.

If you're looking at buying a frame, first make sure it's designed to be built up the way you want (most importantly for you does it have horizontal dropouts). Then measure it and make sure it will fit. Best done by finding a bike that does fit you and comparing the measurements, since building up the frame will cost money.

Also, make sure you have a fork for it. Most likely a 1" threaded head tube, 622mm or 630mm fork. If it doesn't come with one it's very important that the first thing you acquire is a suitable fork. In the event you can't get one you would need to get one custom built and that will be expensive (this will most likely be because the forks you can find that fit look ugly because they're cheap). Best to make sure you can get that custom fork if you need it, before even buying the frame.


Shorter crankset on road bike I’ve been wondering what are the pros and cons of having a shorter crankset.

I’m looking into changing my crank length to a 165mm. I currently have a Shimano FC-RS510 172.5mm upgrading to Shimano 105 FC-R7000 165mm.

Thoughts on this idea? Thanks! I’m riding a Giant Contend AR 1.

There is little research on the impact of crank length on power output in cycling. There are some lab studies, and they seem to show that even for crank lengths significantly shorter or longer than the norm, the metabolic cost to maintain a specified speed or power output in the lab doesn't change. Importantly, some of these studies included lengths ranging from 120-160mm at the short end to 190-220mm at the long end. Sometimes, the very shortest or very longest cranks seem to be more metabolically costly. However, it could be that the human body is fairly adaptable to different crank lengths, and most people can accommodate a given crank length if it's not too far outside their optimal one.
That said, there may be some reason to prefer shorter crank arms. Professional road cyclists seem to be trending in that direction, and I believe that professional triathletes are doing so as well. One stated reason is that, emphasis mine:

According to Trek Precision Fit program manager Matt Gehling, shortening the crankarms and moving the saddle forward means the rider’s legs aren’t coming up as high at the top of the pedal stroke, which then allows riders to drop down lower up front for better aerodynamics, all of which can be done without losing power.
“The big reason the team wanted to try it, and this was at first focused on time trial bikes, was to get their front ends lower,” he said. “A time trial position is the worst thing you can do on a bike for your hip angle, and that is why triathlon bikes come with steeper seat tube angles and shorter cranks; both of these things open the hip up more.

Regardless of the needs of professional athletes, because shorter cranks reduce  the range of motion required at the knee and the hip, they might make overuse injuries less likely, as discussed in the first Cyclingtips article I linked. This blog post by Ridefar and this blog post by a bike fitter both make that association, although do note that this is based in their personal experience.
One of the limits of lab studies is that they are a highly controlled scenario, and they only measure things in the short term. Expert opinion posts can be based on longer-term effects, but one of their weaknesses is that now, everything is uncontrolled - a rider's increased power or injury recovery might have happened for a myriad of reasons unconnected to different cranks. Moreover, experts and their clients are also vulnerable to the placebo effect.
One possible harm of shorter cranks the cadence to maintain a certain power is increased. This means that at very high power outputs, some athletes might have their cadence climb out of their optimal range. However, people can attempt to adapt to this, and most people don't absolutely need to maintain very high power outputs regularly. Riders should be aware that to keep all else equal, going to shorter cranks requires raising the saddle and moving it slightly backward, as discussed by Lennard Zinn (albeit he is discussing the opposite scenario).
I'd probably do the following:

Many serious cyclists benefit from periodic bike fits anyway. If you get one and the fitter indicates that you should shorten your cranks, then do that unless you can see a reason not to. Naturally, give yourself time to adapt, but if you have pain as a result, you should revert. Knee and back pain have many causes, but they sometimes result from cranks too long. If your thighs hit your stomach when in the drops, that might be another objective indicator that you'd benefit from shorter cranks.

In the absence of anything objective, there doesn't seem to be a strong reason to get shorter cranks unless you were changing the cranks for another reason, e.g. getting a power meter, getting a new bike, upgrading the whole groupset.

If you're at equipoise between two lengths, then the balance of upsides and downsides seems to indicate you'd favor the shorter cranks.

If you're very short or very tall, then the common range of cranks is centered around the meat of the bell curve. You might want to experiment with shorter or longer cranks as you are able. For example, I'm a 5' 5" male rider, and I've been successful on 170mm cranks, but I did get a deal on a set of 165mm cranks with a power meter, so I am trying them. Conversely, if you're much taller than the norm, e.g. over 6' 6", then you might not want to choose cranks shorter than the norm. In fact, Lennard Zinn makes custom long cranks (and bikes) for very tall riders, and his experience seems to be that very tall cyclists benefit from very long cranks. Nevertheless, height alone should not compel you to immediately switch.

A digression: the Marginal Gains podcast has an episode titled "Granola and Cargo Cults." The upshot is that in the absence of objective data, we tend to do what our opinion leaders do. This led to a bunch of teams at the Tour de France adopting granola for breakfast because someone in the top team was doing that. Amateur athletes should be wary of following professional athletes just because we want to emulate them or to be seen emulating them. They are a lot fitter and more flexible than us mortals, for one. Hence, adopting the slammed stem position is a choice with a lot of downside for many amateur riders. With shorter cranks, on careful consideration, the balance of upsides and downsides does appear favorable.


Are the numbers on a shifter standardised? My bike has several gears labelled one to six. Do these numbers relate specifically to a certain standard? In other words, would a bike set to say gear four on one bike, perform in the same way as another different bike set to the same gear?

No.

The full gearing ratio of the bike (from your foot to the tire contact patch) is determined by four factors: the crank length, the chainring diameter, the cog diameter and the wheel diameter. Since these components can be changed independently, it is impossible to develop a uniform numbering system for a single component ("uniform" in this case means getting the same full gearing ratio from the same gear numbers selected for the chainring and for the cog).

I.e. even if you standardize the "front gear number to chainring diameter" and "rear gear number to cog diameter" relationships, two bikes with different wheel diameters will still perform significantly differently even when the same gear numbers are selected on both of them.


Can I partially upgrade from Shimano Sora to Ultegra 6800? I have a Shimano 9 speed groupset and I want to upgrade to something that's better on the climbs without shelling out and buying a whole new groupset which would be more money than my actual bike.

Would it be possible to just buy a new 11 speed chain + 11 speed rear derailleur + 11 speed cassette + 11 speed shifters (all ultegra 6800)?

I.e. I want to avoid buying front derailleur + hub + crankset.  Would this work and be worth it?

Thanks!

Stay with 9 speed. the beauty of Shimano 9 speed is that the 9 speed road levers are compatible with mountain derailleurs and vice versa. You can get a 9 speed deore derailleur and a 9 speed 12-36 cassette and Bam! way more gear range. That's literally all you have to buy (and maybe a cable if your old one dies on removal) edit: you will likely need a new chain as well as your current one will probably be too short (but hey 9 speed chains are way cheaper than 11 speed chains!)

If you actually want to go to 11 speed, as stated above you'll need at least chainrings, chain, cassette, shifters, and front and rear derailleurs. It won't necessarily buy you more gear range though, honestly. I believe the ultegra 11 speed derailleurs can still only go up to 32 teeth on the cassette maximum. edit: as @nathan Knutson pointed out, 11 speed road for Shimano uses a wider freehub body (mountain does not, but is incompatible with drop bar shifters/road derailleurs) so you could not simple put an 11speed cassette on your current wheel


Bike tires only inflate up to 30psi with foot pump My bike has sat over the winter, and the tires went flat.  I used my foot pump to inflate the tires (front and back) and both tires inflated to 30 psi.  I have shraeder valves.  The pump continued to working with the same amount of resistance, but the psi on both tires would not go above 30. I am assuming that since the tires did inflate up to 30 psi, the valve connected, air is getting into the tire, and the pin is not stuck. Maybe I am wrong. Hoping someone else has had this issue and can share the fix.
Update. There is no sound of air escaping anywhere. I left the pump connected to the valve over night, and the psi did not decrease. The Gauge on the pump goes up to 100psi.

I don't think it's likely that there's a problem with the valve or tube. You should check it with a separate pressure gauge and try a different pump.


Is is safe to use WD40 as a matte paint protector for a carbon bike? I like to take care of my bicycle and clean it regularly.

After a deep clean I would use Muc-Off Bike Protect to protect and preserve the matte paintwork. This works, but is pretty expensive. I do notice the distinctive WD40 smell when rubbing this solution into the frame, forks etc...

I wonder if the branded Muc-Off spray is essentially a similar formula to WD40 with the addition of a higher price tag or is there something in the Muc-Off formula that isn't present in WD40?

I am concerned that if I use WD40 on my new carbon frame and forks to preserve the matte paint job, it could ruin the pain job?

Has anyone tried to clean/preserve the matte paintwork of a carbon frame with WD40? If so, what were the results and would you recommend it as a cheaper alternative to the Muc-Off product?

Muc-Off Bike Protect link: https://muc-off.com/products/bike-protect

There's not really a generic answer as not all finishes will react the same way to a given chemical, especially over time with repeated application. WD-40 has a bunch of naptha, which generally speaking you want to keep away from paint you care about. It also leaves an oil coating behind that can attract dirt, which is ugly and potentially bad for the finish by itself.

Just use one of the many silicone cleaner/wax/protectant products. Silicone is good because its whole deal is it doesn't harm any finish type on bikes, regardless of specifics.


Shimano tourney 7 speed shifter for rear not working My bike's shifter for lowering the rear gears is not working. It just slide all the way and "click", "click" sound comes but gear does't shift to lower ones. Its currently stuck at the 7th gear and won't shift. The cable also appears to be a little loose. What should I do? Please help.

The cable could have broken, leaving the derailleur sitting on the smallest cog on the upper limit.  I had this a few weeks ago, the cable had broken within the shifter so was not immediately visible.

If when shifting you feel little or no resistance when trying to change to a lower gear this will be a good indicator that this is the problem.