Can disc brakes cause front quick-release to loosen? I just purchased a Yuba Spicy Curry Bosch cargo bike with disk brakes and quick release skewers on both wheels. I haven't had any issues with it so far, in fact, I love riding it, but I have read that using disc brakes with a quick release axle can be dangerous, as the braking force can cause the quick release to loosen and the wheel to fall out. It seems crazy to me. Nobody wants to lose their front wheel riding.

Is the risk overstated? Is it something that only happens with badly designed or improperly adjusted QR/disc setups? I check brakes and tire pressure before every time riding, if I just check the QR as well am I going to be fine?

Would it be safer to just replace the quick release on this particular bike with regular nuts?

I just can't imagine it is a common occurrence, but since I ride this bike with my kid as passenger and share it with my wife, I really don't want to leave it to chance. I am curious to hear from anyone familiar with this particular problem of disc brakes, beyond what is stated in the Sheldon Brown article. Thanks!

Most of the time, a bike wheel spins around the axle. When braking, the axle suddenly wants to spin around the point where the brake caliper is grabbing.

The traditional orientation for a fork dropout, with the opening a little forward of straight down, is such that on a rim brake, these forces pull the axle stubs up into the dropout, and no movement can occur.

On a disc QR fork, this orientation of the opening is a poor choice because the axle stubs want to move in that direction under braking forces. Shifting, or in the worst cases ejection, of the hub can occur. A fairly large number of QR disc brake forks have unfortunately been made that use this orientation. That's a trend that's been changing for a while now, but unfortunately slowly. It is the reason a number of QR disc forks have more forward-oriented openings, which looks funny but eliminates the problem.

Skewers that apply higher amounts of clamping force, such as good quality internal-cam ones like Shimano, counteract this tendency but will not necessarily eliminate it.

Usually lawyer lips are sufficient to make actually losing the wheel impossible, but will still tend to allow the hub to shift if the dropout opening gives it a path to do so.


What do I do if my brakes keep squeaking when I press on them? Do I use lubricant or what? It’s really annoying in public places when I’m trying to stop my bike. Please explain

Answer: NO

NEVER lubricate the friction surfaces of your brake system under any circumstances.  There is NO time where this makes sense, ever.

Do check the duplicate question for answers on how to reduce squeal.

Or embrace it - I had some canti brakes that would make hideously loud noises under hard braking, but under gentle braking they were silent.  After a while I realised that is really a feature, cos hard braking squeals is like a car horn and alerts people to a possible danger.


How can I reversibly uglify a bike? I'm likely to have to commute to somewhere that's less than ideal for security.  The whole thing is less than ideal but it's only for a couple of weeks.

Using using the beater bike I already have isn't an option: it's 23 km under time pressure,  and sometimes I'll have to use the hybrid with child seat (and try to get there in 55 minutes).  I'd rather use the tourer if I don't need the child seat.  In either case I'll take two locks (probably one D-lock and one cable lock, possibly 2 D-locks).  There are some fairly solid iron railings to lock up to, and both bikes are already security marked and registered.

So as an added detterent I'd like to make the bikes look as undesirable as possible -- how can this be done in a reversible way?  While Reduce Resale Value to Avoid Theft? (Uglify) is closely related, the answers there concentrate on permanent approaches, and I'm specifically after something more temporary.

I like stickers. Lots of stickers. Almost anything will do, promo stickers after often cheap and fairly easily available. First put reflective tape on the key areas of your bike, then cover as much of the rest of it as you can with stickers. They will inevitably fade and degrade, but you can help that along by spraying muddy water on them then over-spraying with dilute varnish once the water dries if you want (use acetone specifically to damage the printing if you can).

You can also often downgrade components cheaply - with drop bars hit the bargain bin and buy some cheap, thin bar tape and wrap that over your existing stuff. If you're lucky you'll be able to get two mismatched rolls :) And look out for wrecked bikes and swipe components off them. Rusty, bent seat clamp mounted reflectors, for example. The goal is obvious things that don't affect how the bike actually works.

You could also use packing tape to strap an old torch to the handlebars. Don't use it as a light, it's there because it's big and ugly.

All of that will come off fairly quickly using a plastic scraper and a craft knife, but it'll look convincingly ugly.
For security, I would use secure wheel and saddle attachments (like Pitlock) because that way you can use a grungy old lock around the frame like all the other beater bikes do. Spray paint them black before installing, and don't be too fussy about it. Then get a half decent chain lock (secure, heavy) or cable lock (lighter, not as secure) and thread an old inner tube over it. That way it looks cheap and awful.


What causes the threads on bike pedals to become stripped? Is there something I can do to prevent my bike pedals from wearing out? And what causes the threads on a bike pedal to wear out?

I have a 4 year old Raleigh road bike with just regular open pedals. After 300 miles of riding, I had to replace the pedals because one of them broke off when the threads on the arm that the pedal screws into wore out.

The bike repairman offered to send the pedal out to be re-threaded but that would have taken a week and cost more than just replacing the pedals.

Any suggestions or recommendations?

It probably means that the pedal was never installed correctly: either it was not tightened enough or it was cross-threaded.

It's actually not that hard to install a pedal incorrectly. If you miss perfectly aligning the threads, it's called cross threading. It's possible to cross thread the pedals and still have them feel like the pedal look like it is installed properly.

However, if you look closely, you'd see that the pedal isn't perfectly perpendicular to the crank. When you pedal, you'll feel a pop as the pedal goes around when your foot crests and the pedal (due to not being parallel to the crank) has to change orientation.

Over time movements of the pedal relative to the crank will slowly strip out the threads on the crank, on the pedal, or both.

I could speculate that your raleigh may have been purchased at a department store, and that it wasn't assembled by a professional. They didn't install the pedal correctly.


What is the folded size of ORI AR18 or ORI CR87? I'm assuming ORI AR18 and ORI CR87 use the same frame design and size. I couldn't find any specs on these bikes about its folded dimension.

http://www.oribikes.com/ori/upload/download/2012%20Catalogue.pdf

There's a footnote on page 3 of the PDF brochure you linked:

Approximate unfolded size L:1430 W:550 H:1000 Wheelbase:980 BB height:300 (mm) mm mm
Approximate folded size L:690 W:310 H:630 Volume:0.134 (mm) m
Ori is designed and tested for use by riders weighing up to 100kg


Bike ideas for cross-country - trail biking. I am 6ft & 85 kg What style of bike would you suggest for cross-country trails for a beginner? Think mud and gravel trails (in a coffee estate).

I weigh 85 kg and am 6 feet tall and am looking to spend ~2k USD.

Mainly I am confused about the following aspects:

Cross country or trail or full suspension.
Brakes (should I go for both disk brakes on both front & back).
Rim size
Kind of gears

I have done some basic research but am quite confused with the wealth of information online. Sincerely appreciate some pointers in the right direction.

Unless steep or with lots of tree roots or embedded rocks, those sound like easy conditions for a mountain bike, and almost anything would do. Full suspension would be excess weight for no benefit. On many trails like that you don't even need suspension, just grippy tyres.

Disc brakes are nice, especially in the wet, but not essential in those conditions unless you're going very fast. However assuming you're buying new, decent quality (and plenty of rubbish ones) mountain bikes are likely to have discs.

Gears depend on the hills you expect to encounter, as well as the surface, but at a beginner level you don't need the latest 1x11 setup.

Wheel size, so long as you don't find something out of the ordinary (which makes tyres hard to buy), isn't such a big deal either as a beginner. You probably want either 29" or 27.5", but I'm taller than you and haven't had trouble on 26" wheels.

Overall you want something maintainable where you are, so if hydraulic disc brakes are rare, make sure you've got access to spares and repair services before spedning lots of money on them; if 26" wheels are rare, buy something else, but in many places 26" is a common size.


Are bleeding kit syringes single use? I recently bought a bleed kit (for shimano brakes from shimano) and used it on my hydraulic brakes (successfully as far as I can tell). During cleaning up I noticed the syringe says it was for single use only. This seemed annoying to me at first (produces waste, requires to actually get new ones - shop opening hours / struggle with shipping companies …) so I was wondering what the reasons might be and came up with the following candidates:

They come from the same production line as medical syringes, where they really really shouldn't be used more than once. So the label is on it by default and the production company never bothered to figure out what actually happens upon multiple uses.
The syringe won't be clean after the first usage and the oil damages the plastic over long exposure, so you get traces of whatever comes out of that reaction into the oil, and the syringe won't work properly (piston not tight / piston stuck)
The oil attracts dust and dirt, so after storage I would contaminate my brake with "bike tool drawer dust".
I might not remember if I used a syringe for mineral oil or dot 5.1 / dot 4 and run into danger of mixing the two when using on a different bike, and all just because I tried to safe a few bucks on a new syringe. (or even worse, who says I only use the syringe for brakes? I might mix all sorts of liquids)

You can likely use it multiple times.

Obviously, you don't want to mix different fluids in that are incompatible; you could clean the syringe by drawing in and out a bunch of times, but its probably less convenient than just keeping a separate syringe for different fluids.

They may fail at some point (likely the gasket), but that's probably fine; just use a new syringe when it fails. This may occur between multiple uses if you don't clean/if the materials degrade the syringe over time. But its not a big deal.

Note that even humans  have fairly high success rates reusing syringes, particularly drug addicts in first world countries and oral syringes for babies (which is closer to the type of syringe your bleed kit has). Though, obviously, for medical reasons, you don't always want to (usually don't) want to reuse a syringe.


Need Advice with upgrading Chainrings / Crankset I currently own a 2012 Specialized Secteur and I am interested in upgrading to a 52/36 crankset. I have a the original crankset (S150) and the 50/34 chainrings. My cassette is SRAM Apex, 10-speed, 11-32t

If I have to upgrade to 52/36, do I have to upgrade the crankset and bottom bracket as well ?

Please advice what all needs to be upgraded ? Is the SRAM Rival set a good option ?

Full bike specs are here
https://www.specialized.com/us/en/bike-archive/2012/secteur/secteurcompapexcompact/35153

Because you say you have Apex rings and the specs list the S150 crank, it's not clear which crank you have, Apex or S150. Either could have the rings swapped to 52/36 just by getting new rings. If you were to do that, the simplest path would be getting the SRAM 10spd 110x52 and 110x36 that are still available, although you may have to hunt around for them a little. If you were to use another brand or 11spd SRAM rings, you could probably get it working fine, but it wouldn't necessarily "just work" as easily, may require thin spacers with the 11spd, etc.

If you have any Apex GXP crank you could switch to any other GXP road crank without having to mess with the BB. If you have the S150 that means you've got a Powerspline BB, which can only go on other Powerspline cranks if you wanted to re-use it.

Depending on prior chain sizing choices you may (probably) need a new chain to accommodate the 52. Even if not, it's still a good idea to pair new rings with a new chain. If your cassette is fairly worn it's good to replace that at the same time. Don't worry about it if it's pretty fresh. If it's somewhere in the middle it's a judgment call, but depending on how $$$ of a cassette you go with it can easily be the more economical choice in terms of saving chainring wear.


How do I figure out what crankset replacement will fit my derailleur? I have a bike with a Shimano FC-M560 crankset in the front which I want to replace. I naively bought a Shimano FC-TY301 crankset, thinking that there's norms and that 3-speed cranksets are more or less interchangeable.

Fast forward; the distance between the new crankset's chainrings is larger than the old ones. Since the Shimano Deore LX derailleur doesn't go as close to the seat tube, the chain will rub against the cage when on the smallest chainring.

My question is: How do I select a part that will fit my particular derailleur without relying on the exact series? (The exact components are expensive to get at this point since they're not made anymore).

The service manual here seems to refer to a quantity named stroke, is that the relevant number here?

According to the Bikepro.com bottom bracket compatibility page, the M560 crank requires a 113mm x 68mm bottom bracket (113 mm is the spindle length), which is in agreement with your service manual (113 mm for a 47.5 chainline, or 118 for a 50 chainline).

The Shimano FC-TY301 crankset requires a BB-UN100 / BB-UN26 bottom bracket. The BB-UN100 only comes with a spindle length of 123 mm.

What this means is that you're using a bottom bracket with a spindle length of 113 mm with a crankset that was designed to be used with a bottom bracket that has a spindle of 123 mm. Since the entire crankset it basically shifted a whole centimeter towards the frame, this could be causing the problems that you are describing.

Usually you can get away with using a different bottom bracket with a slightly shorter or longer spindle, but it appears that in your case you require the correct bottom bracket to make everything work properly.


Can I use a 130mm OLD wheel on a 135 mm rear spacing frame to put on a home trainer? I got a hand-me-down home trainer and I want to use it with my disc road bike (with a rear dropout spacing of 135mm).
To keep the budget low, I want to use an old 130mm wheel.
My dropouts are for Quick Release

Can I use some kind of spacers (on the non drive side?) to achieve that?

Since it's on a home-trainer I don't need to brake, so there is no problem of rotor/caliper alignment. However it would be great if I didn't have to tune my rear derailleur each time I swap wheels.

Is it doable or should I just look for a cheap second-hand 135mm wheel?

Can I use some kind of spacers (on the non drive side?) to achieve that?

TLDR:  Try it, see if it works.

Full answer:

Maybe, depending on how much clearance your frame and rear brake have. 5 mm really isn't that much. But without redishing the wheel the tire will be about 2.5 mm off center.  Given most newer road bikes are built to accept 25 tires and quite likely even 28s, you may have to stick to a 23 trainer tire, and even that might not fit.

If your bike is designed to handle 28s, you can probably get away with it without much trouble.

There's also the possibility that the 130 mm rear wheel interferes with your disk brake somehow.  I don't see any way to work around that, should the wheel and disk brake caliper interfere, as any redishing would move the rim and spokes closer to the brake components.

And you'll be lucky if you don't have to tune your rear derailleur at all with such a wheel swap, but you likely won't have to adjust the limit screws.  Some tweaks on the barrel adjuster will almost certainly be needed, as what you're proposing to do is should translate to a "normal" wheel swap, and such swaps often do require small adjustment to the barrel adjuster as the hubs on the wheels being swapped are just a bit different.


Fitting a rear derailleur I'm building a bike from old bikeparts, but i've got a problem. The part that connects the derailleur with the frame doesn't fit, and I thought I would find something on chainreactions, but I can't see anything. Any suggestion?

2 suggestions.

Only change the derailleur, since the new frame should have its own derailleur hanger.
derailleurhanger.com


Can someone help me identify this bicycle? It says it is a Cannondale F400, but it seems those all have forks with suspension.  I am trying to figure out what it is, and it's value, before I move forward with looking at it, but I can't find anything that looks the same, and has the same features.

I can't post the images directly.  Thanks.

http://portland.craigslist.org/mlt/bik/4013428729.html

BikePedia has an entry about a bike that looks to be the same as what you posted.

It's a Cannondale Adventure 400 femenine model.  It appears that this came with a front shock initally, but may have been fitted with a rigid front fork (or there were alternate models without the shock).

These appear to have been produced for several years, with a mostly similar design. I'm not quite sure what year that model is.


Damaged (bent) fork dropout - what are my options? I have an old Dunlop mountain bike - I'm not sure whether it's a steel or aluminium frame. (I have had the bike since I received it as a kid probably 20 years ago.)

For some time, I've had it stored on a horizontal wall-mounted hook in my garage. For some reason, the hook mounting came away from the wall, dropping the bike 4 feet onto the concrete floor. The front wheel was not attached, so the forks hit the ground and resulted in the damage and bending of the left-side dropout you see in the photos.

What options do I have to rectify this damage? I think the blades are still in alignment, so can I bend the dropout back straight and be safe? Or does it really require replacement of the fork for integrity? As stated, the bike is old and honestly in need of a little TLC, but to date has been perfectly serviceable. However, if this would take any amount of money to repair (in conjunction with other possible servicing), it might be more economical to replace the whole bike outright?

Get a frame builder to braze in a new dropout. That dropout is finished and dangerous to use, it has bent too far.


different types of rear shock suspension and their uses? explain me about the rear suspension of mountain bike.

Here is a very rough answer to your very generic and open ended question:

A rear suspension (or shock), together with the front suspension (fork), allows the bike to handle more terrain roughness. This gives you:

safety
traction
ability to go faster

The main two types of rear suspensions are:

air sprung
coil

Generally air suspensions are lighter and better for XC, all mountain, enduro. Coil shocks are heavier, more linear and better for downhill. See What's the difference between All-Mountain, Cross Country, Freeride, Downhill bikes? for a reference on mountain bike types.


Presta valve inner tube issue: area around the valve does not fill up I have this problem I keep running into and it's getting pretty expensive.
I've bought many inner tubes and when I pump the tire up with air, the inner tube fills up really good except in the area where the valve is. That area is still completely flat and I can't figure out why. I use a Presta valve adapter since I use a mini hand pump that doesn't have the Presta pump hole...could that be the problem?

When you fill up an inner tube outside of a tire, the area near the valve will look a bit constricted because the rubber is reinforced in that area:

However, when you fill it inside the tire, don't worry - there's enough stretch in it so that it will expand to the right size and work properly.

The same goes for patches. If you fill the patched inner with air outside of a tire, the patches will deform the tube, but it'll still work just fine once in the tire.


Methods for selling used bike I have a used bike I would like to sell. It's relatively high end (retail price was about $3.5k). I put the bike for sale on Craigslist at what seemed to be a good price, especially relative to others on the site that I've seen, but haven't gotten any responses at this time.

What other methods or services are popular and reliable to sell a used bike?

EDIT:

To be clear, I don't want tips about why my ad might not be good on Craigslist, as that is a very different question and probably not helpful to most readers. I'm curious about reliable venues to sell used bikes from people who have experience with that.

Best methods to sell a bike will vary depending on where you are located.

If you are in North America local Facebook marketplaces oriented to bikes or bike gear can be good. See https://www.facebook.com/groups/dcusedicyclemarketplace/ as an example.

Pinkbike has a buying and selling section https://www.pinkbike.com/buysell/ but it seems to be dominated for really high end bikes (think > US$5K).

The general rule is that if you can't sell something you are asking to much for it. Try checking Bicycle Blue Book https://bicyclebluebook.com to get an idea of how much your bike is worth. Many folks will say BBB values are BS, and I partially agree as values are dependent on many factors, but at least you'll get an idea what you should be asking ($100s vs $1000s).

Post Christmas winter is probably a bad time to try to sell a bike. Wait until the warmer spring weather appears and you may have more luck.


Prescription Cycling Glasses I visited my optician last week and the time has finally come for me to start wearing glasses for driving. As a result of this I figure it is probably a good idea to start thinking about prescription lenses for my cycling glasses too.

Looking on the web, the prescription glasses that I'm seeing are basically "regular" cycling glasses (including regular lenses which may or may not be tinted), plus some kind of insert (clear prescription lenses) which seems to clip to the frame and sit between eye and frame.

The "insert" appears to be shaped to the frame, so it looks like I'd need to buy both glasses and insert, and possibly throw my current glasses away. (I'd rather not do this, but if I have to, I have to.)

I guess my first question, for anyone who already wears prescription glasses, is whether my description above is accurate or not? Second, does having this insert actually "work"? By "work", I mean being able to ride a bike at decent speed, for several hours, up hills, down dales etc. For example, do people experience fogging problems (moreso than you might with non-prescription glasses)?

My next question is more general, a kind of a technology rec. Are there other viable approaches to prescription cycling glasses, that I should consider? For example is it possible to get prescription tinted plastic lenses that will just snap into a frame? (my gut feel is that I would prefer this approach if possible.) [Edit - I've now seen that this approach seems to be available, albeit at a premium (especially as I'd want lenses in at least two colours).]

For the purposes of this question, it's fine to treat money as irrelevant, I can worry about this later.

Please note lastly that I'm not looking for any advice in the general area of cycling glasses here, I've been using them for years and think I already understand the pros and cons pretty well. It is purely the prescription aspect of things, I'd like to know more about.

I'll answer you comment on contacts, as I think you should investigate it.

I had the same dilemma a year ago. After wearing glasses for a couple of years for close up stuff, I was getting to the point I needed glasses while out on the trail. I looked around at options and decided to go down the contacts path. I now wear contacts in weekends and while riding, and have progressive lens glasses for work (computer based) that are suitable (although not ideal) for driving and distance. The glasses offer much better performance when its not raining, muddy etc, but when outdoors (biking, fishing, skiing etc) in all weather, contacts win hands down.

I suggest you discuss contacts this with your optician. There are a vast range out there, from one time use that you take out an throw away to monthly lens than can be left in for a week. Your optician will discuss the in and outs of different types and what suits you, and try various combinations till you get one that works. He will teach you to put them in and take them out - all the stuff that is "creepy" is dealt with - You get shown how to do it properly (and safely), and will be taught how to do it. Although not for everyone, I found it easy to learn to do.

I know you said cost is not an issue - that is good. Contacts are not cheap - initial fitting costs (where they also teach you how to look after your eyes and the lenses) - and cost of the contacts and cleaners mean glasses work out much cheaper.

You may also want to discuss lazer surgery with your optician.


Cannondale CAAD 9 with gravel tires is it possible to fit gravel tires for Cannondale CAAD 9? If yes then can you please suggest some good ones.
The bike looks very similar to the one in the picture.
Thank you in advance.

Most modern road bike rim brakes only have clearance for 28 or 30mm wide tires. Unfortunately I’m not aware of any real gravel or cyclocross tire with less than 30mm width. With disc brakes some road bikes have clearance up to ~35mm width.
Edit: I should add that older brakes and frames have less clearance, the ability to fit 25 or 28mm tires has really only become commonplace in the last few years. Older (or more race oriented) bikes are sometimes limited to as little as 23mm.
Your best bet is probably Panaracer’s GravelKing SK (small knob) which is available in 28mm width and does have some tread (tiny knobs).
However, I don’t think the tiny knobs are going to make much difference for grip (maybe on grass or relatively firm mud).
Low tire pressure is going to help you much more. I’d just get a high quality road tire (e.g. Conti’s GP5000) and run it at as little pressure as possible.


How tight should my front quick release lever be? I'm referring to my first new bike, with a front wheel quick release lever as shown.

The picture is picked from Internet

How can I know whether I have locked my front QR lever correctly? Neither too tight nor too loose? When I tried to open it recently it seemed too tight for me as I was not able to open it.

You are correct that those levers are designed to be opened with your bare hands. Unfortunately it's usually easier to push the lever closed than to pull it open, so it's easy to over-tighten it.

Start with the lever open, and facing back as shown in the picture
Wind the nut on the other side back 2 or 3 turns.
Close the lever. It should be very easy, and the wheel is not properly attached.
Wind the nut in until it is tight (finger tight, do not use tools!)
Open the lever.
Wind the nut in half a turn.
Close the lever. It should be firm, but not impossible.

If it's too hard to close, back the nut off a small amount and try again.
It it's too loose, tighten the nut up a small amount and try again.

Unless you're unusually weak, not being able to open it means it is on too tight. Even if you are somewhat weak, unless you have disk brakes "as tight as you can" should be ok.

Note that if you have disk brakes it is much more important that the quick release be tight. When you use disk brakes the reaction force is pushing the wheel down, out of the fork. It is better to have the QR slightly too tight than slightly too loose with disk brakes.

Also, the QR lever should always point backwards as shown. That makes it less likely to catch on anything and be pulled open (or throw you off the bike).

The link broke, so here's key bits of the article via archive.org and another article that summarises the problem

Disk brakes and quick releases - what you need to know

(Updated Jan 2006 with the first out-of court settlement)

Yes, that's right - a UK cyclist has recently settled out of court with a fork manufacturer, in what is I believe the first successful case of its kind. There are a few more details in this thread here - the rider himself is hoping to avoid the limelight but thought that others might like to know.

The purpose of these web pages is to explain the danger of using a disk brake with a standard quick-release fastening for a front wheel on a bicycle.

This page you are now reading covers the main description for failure, and evidence in support. What happens and why..
This page quotes several experts who have commented on the matter. If you aren't prepared to take my word for it (and why should you?) then have a look at what the independent experts say.
Here is the press coverage.
The CPSC letter gets a page of its own
I've had a problem with my disk brake + QR. What should I do about it?
A chronological look at how this all happened, which will also be kept reasonably up-to-date with the latest news and current status of the problem.
The manufacturers have hardly responded so far, but I'll put up anything more they say.
One year on, and the manufacturers deny they have ever heard of this problem.
Finally, I got hold of a copy of Cannondale's tests. Read and weep (or laugh).
At last, an admission from Marzocchi.

[NB for 'quick release' please read 'conventional axle in slotted dropouts'. A simple nutted axle may be slightly better than a QR in theory, as it can provide a higher clamping force. However I'm not convinced that in practice it is safer, as it will be less obvious if it loosens or slips, and in fact the greater bolt diameter will generate a stronger unscrewing force. The safe alternative is a properly clamped axle combined with fork ends with a blocked exit slot, as shown in the pictures below.]

A brief `Executive Summary'

There are two main aspects to the failure.
The disk brake generates a massive force largely downwards in the direction of the open fork ends. The friction of a quick release skewer is often not sufficient to stop the axle slipping down in the dropout slot.  This is explained in more detail here,
The QR is initially restrained by the retention lip on the fork (assuming it is present), however over time the slipping of the quick release leads it to unscrew, which is described here. Once it has unscrewed enough, it can be forced over the retention lip and the rider will crash.
Below the analysis, we have a section of  anecdotal and experimental support, and I've put the small number of  manufacturers' comments on a separate page.

....


How to determine if my rear axle is bent? When riding, the rear wheel feels as if there is a tiny pebble, stuck within the thread.

The wheel is one week old, the hub is Shimano FH-M475. I have done only very tiny jumps - for example from curbs, but could have landed badly a few times i.e. directly on the saddle. I am 70kg (154lbs).

I don't have rim brakes, so I can't determine if the rim is bent. However,visually, it is fine. My rear tire runs at 4.5 bar (65psi).

Is the axle bent? Is it my fault or can I claim warranty?

To my mind, a 'feeling like a small pebble' suggests something in the hub itself, perhaps a failing bearing. To test for bearing damage, hold the axle in two hands and spin on he wheel. See if you get a regular catching feeling that would suggest a damaged bearing or bearing surface.


Onguard U-lock jammed I'm currently trying to unlock my bike that has been sitting on my porch for a while, the key works and turns, and I can hear the lock engaging/disengaging, however I cannot get the shackle to come out. I think their might be dust/sand stuck in the mechanism however I'm not sure how to get it off now to check.

Get some "Creep" or other penetrating oil (ask at Home Depot or Lowes and they'll point you right to it). This is similar to WD-40 but it foams a bit and seeps in everywhere. Apply liberally both at both ends where the U plugs into the bar as well as where the key fits in (key may turn without the tumblers moving completely).

This will likely loosen things up...a bit of patience and a bit of trying to move the parts around will usually work wonders.

If this fails, apply some more "creep" and use a persuader (hammer, etc).

If that fails, you're going to need a hacksaw and a couple of blades.

Good luck!
Note: This is karma's way of telling you that your bike likes to live indoors when it's not being ridden :-)


How to stop foot clipping front mudguard My feet overlap the pedal and clip the front mudguard when I'm turning at a low speed because I have to turn the handlebars wider than normal.

My foot doesn't clip the wheel when the mudguard is not attached. Does anyone know if this is a common problem and what is done to solve it?

My thoughts are:

Bend the excess metal rods around the outside of the mudguard to lessen the amount of excess rods that can be caught by my foot.
Somehow rotate the mudguard anti-clockwise (as viewed standing from the right of the bike) to lower the excess rods and rubber flap and create more clearance.
The mudguard is not suitable for my bike and I should get another set.

I have a very similar setup (SKS Chromoplastics), and can say the following:

I installed a suspension forks and then the former length of the metal wires bacame too long for the setup. I BENT them in a sharp turn to run parallel to the mudguard (of course it can be bent in any suitable direction, just NOT point straight back like yours). Haven't had any issue yet. I DIDN'T CUT them because there is always a possibility to use the mudguard in other bike with a larger wheel (I use 26in), or to put the rigid fork back. If that happens, I'd just unbend the wires again.
Rotating the mudguard backwards is always good. The more backwards, the less water flying below you. If you have clamped the little "L" shaped metal plate in front of the fork, you can change it to the back part of the fork. There are only two relative caveats:

The front part of the mudguard might become too short, and some drops might start getting on your face at high speeds on rainy or wet days;
If you go down some step or curb, you should take extra care not to hit the rear part of the fender against the obstacle.

Any mudguard like yours is suitable to the bike. Your main problem, as DanielRHicks correctly pointed, is that you should have got the wires short (either by cutting or by bending). Even then, it is acceptable to have a minimal toe overlap. Since you ride platform pedals, I would suggest you to watch yourself if you are pedalling with the foot too much forward ("arch pedaling"). Perhaps you might like to use straps or clipless pedals.

About using a flap, I am ABSOLUTELY CONVINCED that it is very very welcome and extremely useful. Some designs are more flexible, and that work better, but yours is fine, specially if you manage to get the whole mudguard lower than this. I use to say that I'd rather ride without all the rest of the mudguard than without the flap, because it is the actual responsible for a clean and long-lasting chain, and not-so-wet feet.

Hope this helps


What special measures do I have to take to commute in frigid temperatures? Until now, I have been an infrequent recreational (summer) cyclist, but this winter I plan to begin commuting to work via bicycle.  It is a relatively short distance, (approx. ten minute ride), but the temperature in winter can get as low as -40°C (-40°F), although more-typical lows are between -25 to -30°C (-13 to -22°F), with the ever-present wind making it feel even colder.

It generally stays below freezing most of the winter, so I'm not particularly concerned about wetness or slushy/icy streets; my primary concern is temperature.

My bicycle is a mid-range mountain bike -- not super fancy, but not the uber-cheap Walmart variety, either.  (I realize it's not the ideal commuting bike, but it's what I have.) It has rim brakes and trigger shifters for the derailleurs.

At home, my bike will typically be stored in an unheated shed.  At work, there is a heated indoor location to store it.

Snow is generally cleared from the streets reasonably quickly, and I have a dedicated bike lane most of the way to work, so I'm not too worried about navigating the streets in the winter.

This is not a duplicate of What are the minimum requirements to commute comfortably through the winter?, since it deals with moderate New York winters, and I'm asking specifically about much colder temperatures.

I want to know:

Is there any special equipment/care/maintenance I need for my bicycle for it to be able to function appropriately in these temperatures (e.g. special lubricant for the chain, special tires that won't crack in the cold, etc.)?  I have little experience with this, so I don't know whether my bicycle will be sufficient as-is or will need special treatment.
I plan to dress warmly, cover my face, etc., but I'm wondering if there is any special clothing/equipment I need for myself, aside from regular warm winter clothing.
Is there anything else I need to be aware of when commuting in very cold weather?

First of all, I haven’t done anything as extreme as you, only -18°C.

The bike should be fine, maybe use less viscous chain oil and grease. I’ve ridden normal (though quite supple) Michelin Mud2 and Schwalbe Racing Ralph cyclocross tires in -10°C and didn’t notice any difference in their performance. In even colder weather I’ve only ridden studded Nokkian tires. There are special winter tires, e.g. the Conti Top Contact Winter 2 which might be a good idea in any case.

Be aware that cables can freeze and molten snow can form ice on your rims. Regularly check that you are still able to brake, especially before approaching an intersection or the like. Battery powered lights might run into problems (or at least reduced battery run-time).

Regarding clothing: Think about all the contact points between you and the bicycle: Saddle, pedals and handlebar (brakes, shifters). If you can comfortably sit in the saddle with your -40°C winter pants, don’t rub on the crank arms with your -40°C boots and can still shift and brake with your -40°C gloves everything should be fine. For your hands you could get Bar Mitts which allow you to wear thinner gloves. This assumes that your clothing is otherwise suitable for wind and strenuous activity in the cold weather.


Does tightening a QR skewer in different ways affect wheel alignment? Logic tells me no, but if I refit my disc brake wheel and the disc is rubbing slightly on the caliper, if I undo the QR lever, tighten the nut on the other side clockwise and loosen the QR the same amount anticlockwise, then push closed the QR lever again it can correct the rubbing, i.e. it shifts the wheel slightly to one side.
Am I imagining it, or is that a recognised thing of how QR mechanisms work?

It is possible that when you put in your wheel into the drops you are not seating it all the way before tightening the QR.
This can lead to the wheel being slightly off angle that would lead to rubbing.
The fix for this is some people will install wheels when the bike is on the ground to prevent this or alternatively you need to apply pressure into the drops as you close the quick release when the bike is firmly in a stand.
I tend to use the second approach as often when I remove the wheel the bike is in a work stand. I have found that once I reach the normal tension prior to closing the QR usually snug and such that when I close the QR it leaves an impression in my palm, that any alignment issues usually have to do with not getting the wheel all the way into the drops.
Another possibility, which I do not think is the case is your wheels could be out of true and that is fixed by adjusting spoke tension.


Square taper crankset develops play after changing bottom bracket After replacing a bottom bracket with square taper I repeatedly have to tighten the screws that fix the crankset (on each side) to the bottom bracket axle or otherwise I can feel sometimes a slight movement of the crankset on the axle. I understand that this might be needed once or twice for parts to really settle in but I wonder how common that is or wether there are tricks to avoid it. This is an old Shimano crankset and a new Shimano bottom bracket. Since the screws are not very long (about 10mm of thread) I also fear I could damage them in the process.

As some commenters have indicated, your crank arms are worn out.

We can speculate all day about what was the cause, but since you indicated that you felt some wobbling, that means they are now because that is the fast-track to ruining the square taper interface.

You'll have to replace your crank arms.* When replacing them, make certain that your crank bolt is tightened to spec. It needs to be pretty dang tight. Also, when you get the new crank, replace the crank bolts with the snazzy allen headed crank bolts.

*If you are short on cash or like to gamble, you could also just replace the crank bolts with the snazzy ones, then tighten the absolute snot out of the bolts. While a low chance of success, it might work. The BB spindle is hardened steel, and the cranks are aluminum, so you don't pose much risk to the BB spindle if you choose this option. But still abide by the no riding when the crank is wobbling rule.


Electric bike: Do I need display? I'm planning to buy an electric bike kit. However, I don't really like adding the display for aesthetic reason. However, the display (either LED or LCD) has function on/off and low/mid/high power on some model and this confuse me.

Can I just have BLDC motor, controller, battery, PAS, and brake sensor and hope it will work?

If you are building your own kit, you can do whatever the heck you want. The reason pre-built ones have them is both safety and convenience -- you want to know when the e-assist is on for safety reasons, what power mode you're in, and how much power you have left so you're not stuck on the road.

Without blinkenlights, it can be hard to diagnose problems, especially on the road. Is your e-assist not working because the battery is low or dead? A bad main power connection? Maybe the brake-cutoff switch is broken, etc. etc.

If you are aesthetically against the blinkenlights, you can design your own enclosure that is more modest, use dimmer LEDS or tape over them, or relocate them to make them more discrete -- perhaps under the saddle where you can still check them when problems arise.


Are Hövding helmets safer than regular helmets? I would like to know if these very expensive helmets (about 500€) are actually better than regular ones. I'm sceptical about the claim that they are three times safer: if they are so much safer, why do they not seem to be being used by professionals? I cannot find any serious studies supporting these claims, so am wondering whether they are in fact substantiated.

That's the inflatable "airbag" helmet.  It's main claim to fame is that it isn't really a helmet, but sits in a (dorky looking) collar around your neck until needed.

First off, I'm skeptical that the helmet could be tested to most bike helmet standards at all, since the test procedures would not be designed for such a helmet.  So it's pretty much impossible to say if it "meets standards", much less is better than others. For helmet testing info smf.org/standards/b/b90astd (thanks to @Ken Hiatt)

Secondly, the trigger mechanism can't rely (as a car airbag does) on waiting until impact to activate.  So it must trigger based on sudden movements of the head and upper body.  The reliability of this is questionable.  (Keep in mind that a substantial number of head injuries while cycling are due to simply falling off the bike -- the old "forgot to unclip" problem, eg.)

Third, given the iffy nature of the trigger mechanism, false triggering would seem likely, and having the helmet suddenly inflate in a critical situation could be extremely disorienting and lead to an accident that would not otherwise happen.


Is it difficult for one person to ride a tandem bike? About 4 miles away from me, there is a bike hire shop that has tandems. I'm trying to work out the logistics of getting the tandem to my house to pick up the other rider.

I'm an experienced cyclist, but have never ridden a tandem before. It's not convenient for both of us to go to the shop. Is riding a tandem particularly difficult for one person?

I suppose I'll get the bus there...

I have a 1990 steel racing tandem, and sadly it gets more miles solo than with a stoker.

The main differences between tandems and solo bikes apply when riding a tandem on your own (rear wheel cuts corners more, you can't bunny hop)  but points to note:

Cars may not see the rear of your bike, and may not anticipate the extra space required when pulling up or allowing room to turn.
Steering is a bit odd - it may be unique to mine, but if the solocaptain doesn't commit to a corner with enough lean, the bike tries to stand up straight and go straight.
Braking - its still possible to raise the back wheel clear off the ground when doing an aggressive brake with just a captain.  And the stoker's bars may get in the way of your backside if you lean backwards.
Drag brake is less effective with no stoker.  So big descents you have to ride more like a solo bike.
You may get heckled with "Your passenger fell off!" so have a witty retort like "Bugger - so that's why she stopped nagging!" or "Damn I thought we were going slower than normal!"

Speed is generally not an issue - I've topped 40 km/h solo on my tandem, and the previous owner exceeded 70 km/h on it on a race, with two riders.


Stripped threads on left crank on the first ride I just purchased a new road bike and had a friend assist me in the assembly. There must have been a problem because it fell off after only 2 miles of riding for the very first time. I used a pedal wrench and tightened it. The pedal was indicated as being the "left" pedal and has reverse threads.

Now the threads on the left crank are about half stripped. I have successfully screwed the pedal on but am worried about it failing now. The crankset is a Shimano FC-RS500. I would post a picture but I don't want to do anymore damage to the threads by taking it off again.

Do I replace the left crank now or just wait and see?

First thing to check: the left pedal uses a left-handed thread. Was it screwed in correctly? Depending on the amount of damage to the threads, it may be possible to sort-of screw it back in the wrong direction, which will damage it even more.


Any reason for non-continuous mountain road barrier? I have been cycling recently in Polish mountains and when riding through one of less occupied mountain roads, I have found many places where road barrier (that is suppose to secure bikers and car drivers from falling into nearby river) is not continuous.

Some questions around:

Is anyone familiar of those? Can these be found in other countries?
Is there any particular reason for having such risky solution?
What am I missing in thinking that they pose a serious danger?

I was a too-close (as for me) from not stopping before one of these "separation holes" and falling into river, so I'd like to learn as much as possible about these "things".

While this deals with medians and not strictly side barriers, the animal answer is strongly supported by this study:
https://www.researchgate.net/publication/256425278_Potential_Impacts_of_Highway_Median_Barriers_on_Wildlife_State_of_the_Practice_and_Gap_Analysis
A reasonable response would be that there is a drop into a stream that would prevent animals from crossing.  And I agree, and suspect that simple legality is part of the answer.  A law that requires an animal passing gap every X meters may simply have no exceptions for areas where terrain would be impassable for the animals.


Should I be wearing sunblock? I spend the vast majority of my time inside, so I would like to start getting into cycling. I rode up to the beach a couple days ago and got some slight sunburn. I personally don't mind sunburn all too much, but the news has successfully instilled a fear of skin cancer into me.

My initial reaction to articles like: http://shine.yahoo.com/healthy-living/the-new-rules-of-sun-safety-2477938.html that make claims such as:

  It's not smart to go out-of-doors unprotected.

..was that the writers were absolutely nuts. We've spent our entire evolutionary history under the sun - to think that short excursions outdoors would be dangerous seems ludicrous. But then, people are living much longer than they ever did before and, if there are dangerous aspects of sun exposure, the increase in greenhouse gases might be adding to them.

So, does anyone know the reality behind all of this? Should I wear sunblock, or is skin cancer only a risk for people outside all day everyday?

We've spent our entire evolutionary history under the sun, but also aging quickly and dying at young ages. The evolutionary history argument just isn't very compelling.

The current consensus is that sunscreen helps prevent skin cancer, and skin cancer is indeed common. On the other hand, I have seen references to theories suggesting that sunscreen might increase a certain type of cancer or decrease vitamin D production, but these do not seem to be widely accepted. An in-depth discussion of this is probably more appropriate for Skeptics.SE than Bicycles.SE.

In the meantime, just use sunscreen.

EDIT: As heltonbiker pointed out, burning and cancer susceptibility depend on your skin, and most people develop some protection from tanning. I personally wear sunblock during mid-day rides (between about 11:00 and 3:00), when the sun is directly overhead, but I'll leave it off for evening and early morning rides.

If you're burning instead of tanning (even if you don't mind the burns), you're probably getting too much exposure and should use sunscreen more often.


What Cannondale bikes compare to a Specialized Crosstail or Hardrock? I don't know much about bike parts, so I don't really know which make is better, So I hope you can help out here.

As I said I don't really know how they are, but I've always had a thing for how Specialized bikes look.

Now I want to buy something that can be used for both commute and some trail, so I'm looking at CrossTrails and HardRock 29ers... but it turns out I have a 20% discount off cannondale bikes... which is quite appealing. I could probably buy a better bike and pay the same, or just get a comparable bike and save some money. What cannondale bikes compare to those I mention or which should I get so that it would cost me around the same after the 20% discount?

Thanks!

extra..

The Cannondale shop is right in my company's campus so that would make it easy when it needs maintenance.

I can also get 10% off specialized in one specific store, but the shop is  25+ miles away from where I live.. so that could make it troublesome when to take it needs its maintenance)

EDIT:

I've dug a bit into the Cannondale bikes.. how would they compare (component/build wise) to say a Trail SL 29er 2?

Comparing bike brands is exceedingly difficult. A small number of bicycle factories produce the bicycles for many different brands.

Cannondale used to be made in the U.S.A. which made them different from other brands. Now they are mostly made in Asia along with other bike brands.

Here's a quote from about 5 years ago to illustrate the complicated world of bicycle factories:

  Here is a short circumnavigation of the world of wheels. Starting in the old country, Europe, there is the German factory of Villiger/Diamant producing bikes for Trek. Italy's Dedacciai factory does some bikes for Kona. Some Bianchi bikes are still made in Italy too. The Ideal bicycle company has one of its factories in Poland producing bikes for Scott. China boasts the biggest factories with romantic names such as Boan, A-Pro, Sunrise, Kenstone, Kinesis, Ming Kao, Ideal and Giant. These places produce bikes for us under the labels of Norco, Rocky Mountain, Marin, Iron Horse, and Brodie. Taiwan, although not as large of a producer in numbers as China, is a technological leader. The Taiwanese factories of Merida, Fairly and Hodaka produce bikes for Specialized, Kona, and Fuji. There are new frontiers for manufacturing being explored in Thailand as Bangkok Cycle is building some Norco bikes and the Pt. Insera Sena factory in Indonesia creates product for Scott

I'd recommend going to your local bike store and talking to the staff there. If they are friendly, helpful and offer good service buy a bike from them that fits you, is comfortable to ride, and fits within your budget.

If they don't offer good service go elsewhere and find a shop that does.


Campagnolo Super Record H Screw I am having trouble adjusting the shifting on my Campagnolo Super Record rear derailleur. I have set the high and low limit.
I think the main problem now is that the jockey wheels are too far away from the cassette (around 1cm when it should be 5mm). I tried to do this with the H-Screw.
However, when I turn the H-Screw... Absolutely nothing happens. Nothing moves, I turned the screw until it cam out, put it back in, not a single change.
So my question is: How is the H-Screw supposed to work? Is there a spring or something that I may be missing?
In this photo, the H-Screw is fully extended:

In this photo, the H-Screw is fully inserted:

Here is the back view:

Side view:

Is it possible that my chain is too short, or that the derailleur hangar is bent? I can't think of any other explaination.

The H-screw aka b-tension aka angle adjustment is meant to be adjusted in the lowest gear position for any rear derailleur where the guide pulley is offset from the cage pivot, which is most of them, including this. The manufacturer recommended distance will always be for that position.
For conventional road derailleurs like this, that 5mm number really means just short of the chain rumbling in the low gear. Two ways of saying the same thing.
All that said, it's not likely the H adjustment is your problem. It's a subtle adjustment and won't make or break shifting in most cases, the exceptions being if it's way out for no reason or on a derailleur with excess pivot slop from wear.
It's likely you're dealing with one of the common rear derailleur maladies Iike hanger alignment, cable friction, incorrect tension, etc. Hanger misalignment is a likely candidate from your pictures. Eleven speed has little tolerance for it.


Rear wheel tilted on the trainer My bike is Giant Defy 5 and trainer is Elite Rampa. I notice that after putting my bike on the trainer and riding for a while, the rear wheel tilts to one side, usually resulting in the wheel rubs the brake and even frame. I do not have this problem outside. Is there something wrong with my trainer setup? Thanks a lot for your help!

I can't think of any reason that would be migrating in the frame unless it wasn't secured enough to begin with.  You should check the tightness of your quick release.


Can fresh hot asphalt damage slicks? Today I was riding with my road bike when I suddenly hit a patch of hot asphalt. The day before the one side of the road was already filled with a hard first load, so I didn't think much of riding along there again. Also there was traffic on the other side, so I didn't think about going to the left. After maybe 50 meters I felt that there was a sluggish kind of noise and there was steam rising from the ground.

The wheels looked fine as I checked them after the ride, but may they have suffered some substantial damage (security risk)?

I don't think so - I've ridden over 1/4 mile stretches of freshly poured asphalt with no apparent damage to my tires.

The asphalt is around 300 degrees F when it leaves the plant, but it will have cooled to 200 degrees or less by the time it's open to traffic (water will stand on the surface without boiling, so it's definitely below 212F)

Further, unless you're stopped, your tire has a very short contact period with the hot road. A typical road bike tire has a circumference of around 80 inches, and at 5mph, it will be rotating at about 1 revolution per second. If your contact patch is 2 inches long, that means each part of the tire is in contact with the hot road for only 2/80 = 25 milliseconds before having almost a second to cool off in the airflow. 25 milliseconds is about 1/10th the duration of a typical blink of the eye. Or, to look at it another way, each part of the tread only spends about 2.5% of the time in contact with the pavement and 97.5% of the time exposed to air.

The hot asphalt definitely has more "give" than cooled asphalt, so it will feel a bit spongy under your tires, but that's not because your tires are melting.

I'd be a little more worried about the fresh oils on the surface of the asphalt, the oil might degrade your tires if in contact for a long time, and it's super slippery if you hit a wet patch or ride over an iron plate before the oil wears off the tire's surface.


What iOS / iphone app can give me turn by turn navigation of a pre-planned route? What iOS / iphone app can provide turn by turn navigation of a pre-planned (mostly on road) route (stored in GPX or TCX file)?  Voice features are nice, but not mandatory. I've found many apps that will track my ride, or display a route and my position, but none that will direct me when to turn to follow the planned route.  This would be very useful when training for an event where gpx files have been provided, or exploring new routes that I plan to ride in unfamiliar territory.

I'm ideally looking for something like the android cue sheet app.

The RideWithGPS Android and iPhone apps now also offers this with subscription payment.

http://ridewithgps.com/app

As mentioned before, the RideWithGPS website is useful for trip planning, you can customize your cue sheets, save maps and route for offline use, etc.


Clothing advice for beginner I've read online not to wear underwear with bike shorts. Unfortunately, I don't have cycling specific attire.
What would be a best clothing to wear (below the waist, specifically)  for first time 75 km ride on the road?
Riding "Ride For Heart" in Toronto this Sunday, using Norco Cyclocross bike.

Update:
Thank you all for the advice. The ride went well and we finished in about 3.5 - 4 hours.  Avg Speed was ~20 km/h. Highest recorded - 37.5 km/h :)
Used normal synthetic gym shorts with synthetic undies. No rash, but my butt hurts a bit today :)

I'd invest in a pair of bike shorts.

Casual riders going short distances on big comfy saddles can get away with casual or regular sports clothing. You won’t be able to do that riding significant distance on a sports saddle.

Bike shorts have padding, obviously, but are also constructed so there is no seam between rider and saddle. Regular sports shorts have a central crotch seam that is painful to ride on.

The reason to not wear underwear under bike shorts is to not re-introduce seams between rider and saddle.


Am I over weight for this bike I bought My weight is 240 pounds (109 kilograms).

I bought a miele velo gr1 they said it will hold my weight but wheels only have 32 spokes.  Are they right?

The bike should be fine for your weight, assuming you use the bike for its intended purpose.  Which would be on-road riding, not off-road riding or other high impact activities.

For your information, 32 spokes is not that little,  wheels with less spokes are also often rated for up to 109KG.


What's the best way to quickly align front quick release wheel? The front wheel on my bike is quick-release, and I often remove it when locking up my bike. Then when I go to put it back on, sometimes it is a bit difficult to make sure that the wheel is centered properly. I.e., the brake pads are not equally distant from the wheel rim, so sometimes one side of the brakes is a bit too close to the wheel.

I don't want to have to spend a spend a ton of time placing the quick-release wheel back on the frame. That defeats the purpose of quick-release, if it is slow-replace.

What are some techniques for quickly but safely replacing the quick-release wheel with v-brakes?

What I worry about mainly is the horizontal alignment of the wheels and brakes (V brakes or disks). In my experience just pressing fork down on the wheels will then "auto fit" which creates an horizontally accurate alignment.

I press from the handlebars vertically to the ground and the wheel keeps an horizontal alignment with the brakes (accurately set). The operation to press and lock the wheel takes 10 seconds, no more.


road bike - how to choose chainring (crankset) and cassette size? I'm going through a 1st bike build (road bike) and looking for some advice on choosing chainring (crankset) and cassette size.

I'm pretty much decided on the Shimano Ultegra Groupset (6800), which I plan on purchasing from Chain Reaction:

http://www.chainreactioncycles.com/us/en/shimano-ultegra-6800-11-speed-groupset/rp-prod110818?utm_campaign=bazaarvoice&utm_medium=Default&utm_source=AskAndAnswer&utm_content=Default

I've already decided on crank length, so now it's down to chainring and cassette size.

My current cross bike is a Giant AnyRoad CoMax which has a 50/34 crank and 11x32 cassette.  This is pretty much perfect for this bike, on occasion downhill I'll be in 2-11, and on occasion on a super steep climb into the wind I'll be in 1-1.  This bike weighs about 22.75 lbs, and the road bike I'm building will weigh in at about 16 lbs, so I should be going at least a little bit faster.  The spread between the rear gears seems about right, I don't think I would like more fine spacing between gears.

Based on this, my inclination for my road bike build would be 52/36 & 11x32.  The odd thing is that I can't seem to find a single major manufacturer that uses this combination on a high-end road bike.  For example:

Trek Madone (50/34 & 11x28):
http://www.trekbikes.com/us/en_US/bikes/road-bikes/performance-road/madone/madone-9-5/p/1472000-2017/

Trek Emonda (50/34 & 11x28):
http://www.trekbikes.com/us/en_US/bikes/road-bikes/performance-road/%C3%A9monda/%C3%A9monda-slr-6/p/1470000-2017/

Trek Domane SL 8 (50/34 & 11x28):
http://www.trekbikes.com/us/en_US/bikes/road-bikes/performance-road/domane/domane-slr-8/p/1477400-2017/

Trek Domane SL 6 (50/34 & 11x32):
http://www.trekbikes.com/us/en_US/bikes/road-bikes/performance-road/domane/domane-sl-6/p/1460000-2017/

Specialized S-Works (52/36 & 11x28):
https://www.specialized.com/us/en/men/bikes/road/performance/sworks-tarmac-duraace/128538
https://www.specialized.com/us/en/men/bikes/road/performance/tarmac-pro-ultegra-di2/118441

Giant TCR (52/36 & 11x28):
https://www.giant-bicycles.com/us/tcr-advanced-sl-1

Felt FR1 (52/36 & 11x28):
http://www.feltbicycles.com/Global/2016/Bikes/road/race/FR/FR1.aspx

Is there some reason 52/36 & 11x32 seems to be a taboo choice by manufacturers?  The 11x32 I'm running on my cross bike currently seems to provide a fine choice between rear gears, if anything I wish the difference between gears was not quite so fine, so sticking with 11x32 at the rear and upping the front from 50/34 to 52/36 to adjust for anticipated slightly faster speed all round seems to be the natural choice.  Anybody have some thoughts or advice on this?

The main reasons your combination is avoided are as follows:

It would require a long cage derailleur. The maximum a Shimano short cage derailleur can handle is 33 teeth, and your combination would require 37 teeth. Long cage means extra weight, wind resistance and cost, none of which the manufacturer wants.
34/28 is already extremely low. Not many people who ride racing bikes need gears lower than that. Compare that until few years ago, the standard used to be 52/39 and 12-23.

Of course, since you are building a custom bike, you can just order a long cage derailleur and build what you want.


Why does the rear hub (cassette) moves on the axle when I pedal? I am new to this website. I am also new to the terms, and names related to bicycle components.

I have a bicycle called a Burner SuperCycle.

I went to the repair shop twice in the last year because things started breaking down. I am not using my bike in an extreme environment. Just in the street of my city. What I have noticed is, after a while, I start hearing a strange noise when I pedal. And with time it gets worse and worse and now it's just too much.

A couple days ago I decided to investigate by putting my bicycle upside-down and pedaling manually. There was no strange noise but the rear hub/cassette was moving up and down in a circular manner on the little bar that goes trough it (I don't know the name, sorry).

So I have a strong feeling this is where the sound is coming from.

What should I do next? Take off the whole wheel? Tighten up something?

It's almost certainly a bent rear axle.  I'm willing to guess that you have a freewheel design, where your rear chainrings have the freewheel mechanism integrated.  The assembly then screws onto the rear wheel.  This design was universally used from the mid-80s back, and is still used on low-end bikes.  The design works ok for single-speed bikes, but as you add more gear sprockets on the back, the drive-side wheel bearings (at the edge of the wheel hub) must be further and further away from the frame.  The resulting forces are notorious for bending axles, even with good quality axles.  I've broken one axle cleanly through because of this issue.  On a low-end department store bike like yours, the axle is probably even weaker, so it's not surprising that it would bend, even if you haven't been abusing the bike badly.

You should be able to replace the rear axle, assuming that there is no additional damage.  It's probably best to take the bike to a bike shop, since the work is a bit messy and is a little finicky with reassembling and adjusting the hub.

If you wanted to do it yourself, you should do a bit of reading on how cup and cone rear hubs work (Sheldon Brown's site has some nice diagrams and advice: http://sheldonbrown.com/cone-adjustment.html and http://sheldonbrown.com/tooltips/hubs.html).  Then you could disassemble the wheel bearings, pull out the axle, find a matching replacement, then reassemble.  You would need wrenches to remove the rear wheel nuts, cone wrenches and grease to reassemble and readjust correctly.


Listening to audio without obstructing ears I'm looking for a way to listen to my audiobooks while commuting without obstructing my ears.

One (rather expensive) option appears to be the Tunebug Shake (a Bluetooth turn-your-helmet-into-a-speaker gizmo); however, I'm hesitant to spend $120 on a device made by a company which does all their consumer promos with skater-style helmets and doesn't answer emails asking questions about sound quality with vented helmets.

Another option would be a water-bottle speaker (I commute with a Camelbak -- this is Austin, after all -- so either of these mounts are fine). Obvious downside is positioning -- my two water-bottle cages are below and behind my ears -- and several of the commercially available devices are specific to Apple hardware (and the thought of buying an iPod rather than using my existing Android-based phone smarts a little).

Suggestions? Experience?

I'm assuming you want those more to be able to hear traffic, less because how unobstructed ears look. I use a pair of cheap sony ear plugs. They're the kind of plugs that don't go all the way in the ear, but are only small round bulbs that sit at the front. Thus they still allow me to hear everything around me perfectly.


How to make my wife's bike lighter? Is it worth the cost? We inherited a Huffy Stone Mountain 26" mountain bike. We live on the 3rd floor of a walkup. It is quite difficult for her to carry the bike up and down the stairs.  It has a fork with a spring suspension. Other parts of the bike look normal. When I pick up the bike, it seems to be front heavy.
I'm not sure how much the bike is worth now...maybe $50 bucks maybe a little more? Is it worth trying to tweak it to make it lighter or should I just trade this one in?

Difficult to say without knowing more about the bike, but I'd trade it in for a better bike; Huffy has a rep for low-end, tank-like bikes. From your description, you'd need to replace the frame and front fork to see any significant weight savings.

Something with an aluminum frame like a hybrid bike would probably be easier to carry up the stairs, even though aluminum will give you a harsher ride.

Suspension forks are heavy, particularly on low-end bikes. Suspension usually makes sense for off-road riding. If your wife mostly rides on pavement, you can get a bike without suspension of any kind.


Effects of jockey wheel sizes & types I'm wondering about the variations in jockey wheels / derailleur pulleys and what differences they make; There's a lot of conflicting and confusing information out there, so I'm after some general opinion on them.

Common sizes appear to be 10T, 11T, 13T. I can see that the larger the pulley, the lower its rotational speed and chain bend and thus the less friction it will cause, at the expense of some weight and space. Some stock pulleys are apparently over 30g, and some light alloy ones are under 10g, which is a reasonable range for the weight weenies to fuss over!

Larger jockey wheels will require a longer chain, which I've seen described as also increasing gear capacity; is it effectively like having a longer cage? If so, is it reasonable to use a 13T bottom pulley to gain capacity?

The upper pulley is clearly going to affect shifting most, as it feeds the chain onto the cassette, so a larger pulley will move the chain closer to the cassette - is this likely to reduce capacity?

I've seen jockey wheels sold in pairs specifically labelled as upper and lower, and often one of them will have some degree of float or play, rather than being rigid on its axle.Is this meant to make it more forgiving of slightly misaligned gears? Is it necessary if you have well-aligned gears?

Alloy pulleys seem to be more highly regarded than plastic. Is it also the case that plastic wheels may have more flex than alloy ones, providing float-like behaviour in the wheel rather than the bearing?

Bearings will usually be smoother and lower friction than bushings, and ceramic bearings are better than steel - but how big is this difference?

Main gain is less friction when using ceramic ones and less friction on the transmission when using up to 15T pullies. This translates into couple of watts after a big number of km's.

If you are into pro racing or you are a really weight weenie or you just have money to burn, then you can go and change both pullies if you want to. From several studies, at very high performance you inded gain some power from using larger pullies, but that is really almost irrisory and only really valuable at really high performance levels, say pro riders at Tour de France, Vuelta, Giro, etc. Other than that, ceramic ones have less friction so is supposed to save you some watts on long rides, which translates on some miliseconds on the clock after couple hundred km's.

If you check prices, good ones are up to 400 usd...so, what you will do, change pullies or fully upgrade your transmission? I'll go for the 2nd option ;)


Longer pivot bolt for the front road brake? On a roadbike, I want to mount dynamo front light on the brake pivot bolt bracket (because my handlebar is occupied with gadgets, and because I want to use the handlebar bag which obstructs the light). Naturally, there is no extra length in the bolt, and the standard solution is a longer recessed nut.

Unfortunately this does not work with my fork: the nut does not go down further than the designed one (I realized this having bought a longer recessed nut after asking a related question earlier).

The only solution I see is a longer pivot bolt. Is such thing available? Or is there any other way to mount the light above the wheel, below the handlebar bag? (I do not want to put the light any lower.)

The brake is Sram Force 2012 (if that matters). I'm ready to replace the brake if another model allows for a solution.

Some caliper rim brakes do have interchangeable pivot bolts and accompanying hardware available, either explicitly or by way of what are usually simple hacks. Within Tektro brakes for example, many of the brake arms use the same bolt style and hardware and can be switched between front recessed, rear recessed, front external nut, and rear external nut mounting if you have the hardware to swap around, which can be useful at times in the shop when you need a certain color, reach, front/rear position, and nut style permutation right now. Tektro makes a product that supports this so you don't have to go cannibalizing other brakes. But none of that applies in any way to a Force brake, or if there were a way of getting another company's external nutted pivot hardware on there (which would be one way of solving this, probably) it would be an experiment and a more fabrication-requiring hack. Your brakes don't have any pivot hardware offered aftermarket by SRAM.

If you're willing to change the brake, you may be able to get a front brake intended for external nut mounting to work. I say may because you'll probably need to trim the bolt some to work with your recessed nut, but they only give you so much threaded length to work with, so you'll need to have enough threads falling in the right area. I believe all or almost all brakes have threads that can't be extended with a die because the material isn't there to do so, either because the threads are rolled or some other reason. Another potential solution if that becomes a stumbling block would be putting in some spacers in the recessed part of the fork and just using an external nut.

Another approach is using one of the generator light brackets available that are somewhat intended to address issues like this by only adding a bare minimum of material behind the caliper. (Maybe you've already looked at this; I offer it in case you're running into the issue by trying to use one of the chunkier generator light brackets out there, such as the plastic ones.) An example would be the B&M 471F:

Many people who ride road bikes with handlebar bags, such as randonneurs, use handlebar bag racks and other front racks with integrated light mounting for generator lights.


Fork swap possible or not worth it? Fat bike tapered I got a Fat Bike With a FAT Fork that is tapered. For summer riding, I swap out to a 29+ 2.2” Wheelset.   However, That Fat fork just feels like an anchor and I’d love to be able to swap it out too for a slimmer, lighter Surly Ogre or Krampus fork. IF POSSIBLE.  These Surly forks are a strait 1-1/8” tube.

1) Can I use some sort of tapered to strait adaptor?  And how complex for a non-mechanic/ tinker level novice?

2) Are there comparable tapered forks like the Surly ones mentioned I should consider instead?   I want something with a lot of mounting zits for bikepacking.

3) Other solutions besides buying a new bike?

This is my Fat Bike spec:

All you have to do to use a straight fork like a Surly is put a reducer crown race on it. The one for this would be FSA part number 160-5540.

Steel forks with tapered steerers aren't popular because things get so heavy. I don't know of any, although that doesn't mean there aren't any. There are some carbon ones like the Salsa Firestarter.


What to do after an accident with a child? I was biking home last night and had a minor bike accident with a child of around 12 or 13. It was around 6pm on a mixed use pedestrian+bike path and completely dark, with little lighting on the path.

I was going uphill maybe going 8mph, he was on the downhill. I was well lit (headlight + white flashing light on the front of my bike, with full reflectors including reflective vest), he was unlit, no reflectors (except half a yellow reflector on one pedal). I saw him at the crest of the hill, he was on his side of the path, I was on mine. Then not more than 10 or 20 feet in front of me, he suddenly swerved into me. I was against a fence and had no where to go, so I yelled at him and just clamped on the brakes as hard as I could before he hit me.

I think the left side of his bike clipped the left side of mine, but both of us ended up on the ground, he seemed ok, and got up on his own after laying there for a moment -- he did have a bleeding finger, but he was able to bend it without pain. He wasn't wearing a helmet.  I asked him where his mom was and he said she was biking nearby, so I asked him where I could find her. He called her on his friend's cell phone (who also had no helmet or lights or reflectors) and told her to come.

I asked if he was ok or if he hit his head, he said he was fine and didn't hit his head. Mom showed up a few minutes later (no lights, reflectors or helmets) and said "What did he do?" so I told her what happened and pointed out that he needs to have reflectors and a helmet, and she said "but it was light out when we started riding". I also told her to check him for head injury just in case he hit his head on the ground, and she kind of rolled her eyes at me. My bike was ok, I was ok, he seemed ok, and mom just wanted to leave so I just left it at that and continued home without incident (I did discover the next day that my head light was scraped up and the light mount was cracked, but I had a spare mount so that was easy to fix), but after leaving I'm wondering what else I should have done?

We didn't even exchange last names, I got one picture of him and his bike with my cell phone camera but that's it.

Should I have called it in to the police? California law requires riders under 18 to wear a helmet and to have lights at night. Should I have said more to the mom about helmet and reflector use? Should I have gotten his full name in case I discovered significant damage or injury later?

Or since neither of us was injured was just biking away the right thing to do?

This is my first real accident in over 15 years of riding, I always figured that when I did have an accident it would be with a car, I never thought that it would be with a snot-nosed (literally) kid on a bike path.

Where I live there is a legal requirement to report any injury accident to the police, and from past experience they would call a bleeding little finger an injury. However, I personally would not bother for such a minor injury, they will fill the report and forget all about it.

As far as other legal issues (Again, speaking from my own) - you stopped, ascertained injury and damage and rendered assistance - you fulfilled you legal obligation.

It appears that you did way more than was really needed, and had/have real concern for the other person -  there is little else anyone can do, especially if offers of assistance are turned down and advice is shunned.

On the issue of lights and helmets - there is not much you can do about it and you went beyond what is morally required (Sounds like mum probably thinks way beyond).

A couple of weeks ago a friend of mind had a teenager (No helmet) T-Boned her car at an intersection - he came off a foot path at high speed and could not stop. He and bike flew over car bonnet leaving a small dent, he cracked his head on landing. Although dazed, he refused offers of help and a ride home etc, and rode off before an ambulance was called (Here there is no cost for medical treatment for accidents), despite several bystanders "suggesting" that he needed to be checked out. What else could she do?  These things happen - especially with kids and teenagers, as long as no one is seriously hurt, it's a good day


What are compact cranks? In overheard in a post ride discussion this morning about wanting a set of compact cranks.
My search on bicycles.se has only found this question with them in the title, but the answers don't mention exactly what they are.

Are they similar to the old biopace cranks?

They probably weren't talking about the cranks per-se, but the whole crankset, which is the cranks and the chainrings.

Compacts are cranksets with smaller chainrings (typically 50 teeth and 34 teeth) as opposed to standard cranksets which have say 52:42. Combined with wide-range cassette this can give a good range of gears without having to have a triple-ring.

Biopace were oval rings - you can get non-round chainrings for either compact or regular cranksets.

Note that the cranks themselves do come in different lengths to account for different leg-lengths, but this is independent of the chainring diameter.


What do I get by paying more for a bicycle? I am not experienced with bicycles, although I have been using them for years to get to work, as well as to go out in the countryside (dirt trails) to take nature photos.

I have used affordable B'twin bikes and I was generally happy, but after my last bicycle was stolen I am looking to step up a bit. There are countless articles on the internet suggesting not to spend too little. But I find it very difficult to find anything tangible or easy to understand about what precisely one would really get by paying more.

Take for example the Rockrider 520, 540 and 560. (I am linking the English Decathlon site so people here can read it, but I do not live in the UK.) I am looking at these: all of them are better than what I had. The price more than doubles when going from the 520 to the 560. I look at the specs, but I am unable to translate them into what I could do with the 560 that is not possible with the 520, or how the experience would be different.  I am looking for help with this, especially advice that I could translate to other models as well, although it is these three that I am looking at now.

All of these are marked as:

  Not suitable for XC, All Mountain, Enduro and BMX.

This restriction seems to cover all forms of mountain biking (which is puzzling) and some websites suggest to dismiss all of these bicycles from the start because of this note. However, the cheapest model from Decathlon that does not have this note is 50% more expensive, way more than what I can afford (where I live, it's actually 2x the price of the discounted 560).

To sum up:

For any bicycle I pick, it is easy to find another one that is two or four times as expensive. How can I better understand what one gets in practice for paying more? The specs often just mention components of a certain brand, but it is hard to even see which component is better, not to mention how having a better component translates into riding experience (please see the specification lists I linked).

When looking at the three choices above, my spouse asked me "Even the cheapest one is better than what you had. What would you gain by paying more than that?". And I could not answer. What I really wanted (bigger wheel, better gear range and theoretically better brakes) is indeed present in the 520 already.

As to the question "why a mountain bike", I would like to be able to go on rougher trails (rocks, roots) without too much worry. I would like to learn how to do that safely and efficiently. However, I am not young and sporty or physically skilful person. I also keep thinking that my own physical limits may be reached much before that of an expensive (for me) bicycle.

With so many good answers I hesitate to say anything.

But, in an effort to add something useful to the conversation...

The Value Curve
Part of the reason it's hard to understand the difference between more and less expensive bikes is that you do get what you pay for, but cost increases faster than value.

What is Value?
For the purposes of this answer I'm defining "value" as some measurable improvement.
For example, a $15 steel chain that will last 3,000 miles vs an $80.00 stainless steel chain that will last 8,000 miles (made up numbers - this is only an example)

Why is There a Curve?
The cost to manufacture increases faster than value. Each improvement cost more to manufacture than the last one.

For Example
It's easy to see a difference between a $50.00 bike and a $400.00 bike.
It's harder (not impossible) to see the difference between a $800.00 bike and an $1200.00 bike.
As price goes up it gets harder and harder to see an increase in value.

I would argue that at some price point there is no value increase and you are paying (hopefully) for craftsmanship, like extra polish or fancy lug work or exotic materials that are expensive but don't contribute to a measurable difference.

Suppose I agree that there is a value curve - what should I do?
There is a "sweet spot" in the curve. A place where you get the most bang for your buck. The problem is that I can't tell you exactly where that is because it changes over time and it depends on the individual's situation - finances and type of riding.
Bike shoppers have to balance their budget with the desired level of performance and decide where their sweet spot is.

Always test ride bikes before buying. Always ride more than one so you can compare.
A parking lot is not a great way to compare ride but it's much better than nothing. Bike feel matters.


Which holes to use for mounting rear rack? I just got a rack to mount on the rear of my bike frame, but I'm puzzled at which mounting holes to use. On the right side of the bike there's an obvious screw hole for mounting, but the corresponding spot on the left side has something in the screw hole so I can't use it. Hopefully you can see the silver obstruction in this picture -- mounting hole would be just above and to the right of the axle.

The other screws are holding on the disc brake, so I don't think I want to mess with them.

The bike is a Trek 3500, the rack is a Blackburn Local Spring Clip.

Looking for advice on how to proceed with mounting this.

The quick release skewer is the lower mounting point, remove the skewer pass it through the rack and reinstall. After the lever is tightened, verify that the threaded rod end comes to the edge of the acorn nut. If the threaded rod is not visible you will need to source a longer skewer.


Safe steerer spacers stack height I'm building my first road bike, which means I'll have to find appropriate bar height through personal experience and cut the fork steerer in process at least once. I plan to start with the following combination, from down to top:

8mm conical spacer that came with headset.
20mm and 10mm spacers.
40mm high stem.
5mm spacer.

In summary, 38mm before stem, 5 after, resulting in total of 83mm of exposed steerer after cut. The fork has 1 1/8 inch (~28mm) tapered carbon fibre steerer, without metal liner inside. Headset is integrated, upper bearing is almost flush with head tube.

Will it be safe or I'll have to cut shorter? Fork manufacturer did not answer the question. I do not plan to ride out of saddle too much, at least during initial fitting, so bars won't experience significant load, and I'm pretty lightweight.

A total spacer height of 30mm below and 5mm above is quite typical, and certainly nothing to be worried about.  The most important thing, since you have a carbon steer tube, is to make sure you use the proper compression plug and the specified amount of torque when assembling it.  Also make sure the top of your top spacer is just slightly higher than the top of the steer tube, because the top cap needs to rest on the spacer (or stem), not the tube.

Don't forget you can achieve some bar height adjustment by flipping the stem, too.


How do I maximize my upper body workout from riding? I often hear people say “your bike is a whole-body gym”. I know my upper body workout will never be close to the workout my legs get, but so long as I’m a bike commuter, I figure I ought to get as much as I can out of it. I have a Trek 8.3DS, flat handlebars, no bullhorns, no upright grips.

How do I adjust my riding style/choice of bike/choice of equipment/types of rides to maximize whatever upper body exercise biking can give me?

The "pure" answer to the question as asked is probably as others have said, climb as much as possible.  But perhaps a better answer is to admit that cycling is awesome for aerobic fitness and leg strength but not as great on the upper body.

Obviously, cross-training is an option, but even if you are 100% committed to your bike, you can probably get significant results from two common calisthenics pre and/or post ride: Push-ups and Pull-ups.  The key is that you want to develop your chest/shoulders/triceps (pushing) and your back/biceps (pulling), and doing multi-joint exercises is likely more efficient/helpful than isolation exercises.  If you can't do pull-ups and don't have access to a lat pulldown machine you can help yourself by using your legs to give yourself a gentle assist.  If you have or can scrounge some dumbbells you can do a bit more.

Try this:

Do a set of 20-25 pushups, then 8-12 pull-ups, either just before or just after you put on your shorts/jersey.
Do a second set 5 minutes later after you've made up your water bottles, etc., put on your shoes, whatever.
Pump up your tires and get your bike "ready," then do a third set.

Go for a ride, and try to get in as much climbing as possible.  You'll probably be amazed at how quickly your strength will improve just with three sets of good form concentrated upper body calisthenics pre-ride.  Again, if you have dumbbells or a weight bench you could do bench presses/military presses, or laterals, and you could do rows to help with the "pull," but the goal isn't really do to a full on weightlifting session, just some quick calisthenics with one effective push and one effective pull exercise and at least two, preferably three sets as you prep for your ride.


What makes grease appropriate for bikes? I'd like to grease my seatpost, and in front of me I've got a tube of "CMD Extreme Pressure Lube #3" that claims to be good for "ball bearings, roller bearings, deep drawing, rivet spinning" and a host of other industrial applications I don't understand.

Is this likely to work well?

If not, what makes grease appropriate? I'm sure I could pick something "specifically intended" at the LBS tomorrow.

Phil Wood, the owner of the bicycle tool and components company of the same name, once commented that his number one requirement when he was buying barrels of grease for his company, was that it be the exact same green color shade as the previous batch, so that he didn't get too many phone calls asking what he'd changed.

Point is that the "bike specific" greases generally aren't.

As far as functional necessities:

Not too thin - A thin grease, like Slick Honey, will run very smooth, but only for a very short time. If you want ideal performance, and don't mind overhauling your bike every couple weeks, use this.
Not too sticky - Motorcycle/Automotive type bearing grease tends to be very sticky and very thick. They are designed to thin out at higher levels of heat and friction than a bicycle will reach. So it will last a long time, but will feel tight, and add friction to your bearings.

Generally, buy a tube of Phil Wood or Park tool grease, and feel free to use anything with a similar purity and consistency in the future.

Edit: After reading Matthew's answer on this page, I realized I hadn't pointed out the 2 cases where the grease matters. In the case of Carbon, see here. In the case of Titanium, with any non carbon frame, you must use a copper paste grease, commonly sold as TiPrep. it is messy, annoying, gets all over everything, but it stays put, which no other grease i am aware of does for Ti.


Rear red light with seat bag My bike has this red reflective light right below the seat (I don't know its name), and I'm thinking of buying a seat bag such as this one. Won't the light be covered? Isn't this potentially dangerous? How does one fix it normally?

The reflective brand name tab on the rear of that seat bag is a light holder. You will most likely need to remove the light from the seat post. Hopefully it has a clip styled mount, otherwise you can get a light that has a clip mount.


Chain doing noises... what to do? I have a city bike with a 3 gear hub on the back.

From some time now, from time to time I hear (I think) the chain clicking/cracking (noise) specially when going up a ramp.

Initially I though it was just missing oil, but after greasing the chain it still does the same noise.

Any tips to solve that?

Extra info: When I hear the noise it seems like the chain jumps in the cog?!?! I am not sure though.

Sounds like your gears need adjusting. How to do so would depend on the type of the gears you have exactly.

But if you're getting the clicking and jumping gears, then your gears are out of index.


mtb hubs why is his hubs louder but on paper they are the same My mate and I purchased bikes.   I got a Norco HT 2 and he has a Norco FS 3.
On paper we have the same hubs but mine is silent, and his is decently loud when coasting.  Why is that?

Something happening inside the freehub is different. Possible variants that I can think of:

One hub has more or different thicker grease on its pawls (or equivalent parts responsible for  enforcing the one-way rotation). The grease adds "liquid" friction between the parts, preventing them from smashing as fast against each other with every step of the ratcheting mechanism. Without enough kinetic energy present in pawls to be dissipated as heat/sound, the clicking is not as loud.

One hub is older/newer, and its pawls are worn/fresh. Again, the pattern of the pawls striking against their counterparts may affect how loud the sound will be.

Hubs have slightly different internal design even if they are marked with the same model name. Their internal components may be from different production batches, or minor revisions can be made without changing publicly visible names of products.


If many bottom-outs are happening, should air pressure or compression damping be increased? I know springs exert a force proportional to displacement from a steady-state position. On the other hand, an ideal damper exerts a force proportional to the speed of the object.

The procedure to tune an air fork that I have been taught is:

Set positive chamber air pressure according to a table with rider weights or by measuring sag.
Set compression damping according to current trail conditions each time. Aim for the least amount of damping which still avoids repetitive bottom-outs during the ride.

But I still struggle to understand why to increase compression damping instead of positive chamber pressure. What would be the difference?

Increasing positive chamber pressure would reduce bottom-outs, but at the expense of reduced "up" travel.  Increasing compression damping will also reduce bottom-outs but without reducing "up" travel.  This would have the negative effect of reducing the shock's compliance which will make the ride harsher, so it's a balancing act where the goal is to optimize the shock's action for the riding you do and how you want the shock to work for you.  If you mostly ride smooth trails but with occasional drops, then increasing positive chamber pressure so that you can keep compression damping low while still not bottoming out very often might work best.  If the shock is bottoming out every time you hit a big rock, then may you have to increase both positive chamber pressure and compression damping.

If you can't find an effective combo that doesn't reduce bottoming out, then maybe you need a longer-travel fork.


I sit real far back on my saddle Asked this on diaspora, but was urged to come here, so, here's my question:

I tend to slide BACK on my saddle really far, to the point where my sit bones are very near to the edge. If I try to scoot forward, it's markedly more uncomfortable for the soft tissues and the angle of my legs doesn't feel right. The bike frame itself is the right size-- the shop helped me with that. So I don't know if I just have a big ass, a weirdly long torso, or what?

I was told that I should never, under any circumstance, adjust the seat further back on the post, but I'm somewhat at a loss of what I should do to fit my body's dimensions.

Also, I need a new saddle anyways, so any suggestions would be helpful. (Assuming they won't cost me an arm and a leg. I'm unemployed, after all.)

As others have said, just because the bike shop says it's a good fit, doesn't make it so. Their incentive is to sell a bike off the floor so they'll find the one that fits best and sell it to you.

I got a custom fit and I have longer thighs than most people. This meant that to get the seat position right, I had to have my saddle further back from the pedals than is typical. I ended up getting a frame built to my measurements.

It's possible you have the same setup. If you can't afford a bike fit, then look for a "setback seatpost" and you can do some trial and error.

The goal of having the seat in the right position for you is to allow your legs to cantilever your torso and "unweight" your hands, arms and shoulders. Here's an article that talks about the benefits of unweighting your arms and how far back to set your seat to achieve this.