Most common mechanical failures?

[telstarbox]

Inspired by the spare tyre thread.

Apart from punctures, what are the most common mechanical failures you might encounter on a ride? (Let's say in the UK on tarmac roads, on a bike which sees a bit of cleaning and servicing now and again).

[quixoticgeek]

Inspired by the spare tyre thread.

Apart from punctures, what are the most common mechanical failures you might encounter on a ride? (Let's say in the UK on tarmac roads, on a bike which sees a bit of cleaning and servicing now and again).

I'll reply in 3 weeks, I've got a couple of big rides planned and don't wanna Jinx it :p

J

[zigzag]

if the bike is being looked after and not mishandled there should not be any mechanical failures really.

very rarely: spokes break, chains break, cables snap, inner tube valves fail, shifters fail, rims crack etc.
extremely rarely: frames crack, forks and steerers break, handlebars snap, seatposts snap, saddle clamp bolts break, saddle rails snap, cranks break, hubs crack etc.

i would rather ensure that the bike is in good order instead of worrying what can break/fail

[hatler]

The only true failure (as in, I wasn't able to complete the commute) was a combination of a puncture, and a vital bit of my pump being absent (dropped out I suspect).

I got away with a chain failure one time because I was only 20 yards from my front door. (Never buy a Taya chain.)

Beyond that, the odd spoke or two have pinged (but that didn't stop me rolling) (and I haven't had one of those since I bought a proper set of wheels), a rack lug pinged off the frame, a brake cable snapped, and that's probably it.

All this in 14 years of commuting averaging about 2500 miles/year.

[Kim]

Off the top of my head, in approximate order of frequency:

-Bent chainring guard, especially if there have been trains, cars or Silly Sustrans Gates™.
-Mis-aligned lights (see above).
-Brakes/gears needing routine adjustment.
-Derailed chain requiring oily fingers and foul language to rectify.
-Mirror's a bit slack.
-Knee/lung/digestive system problems^[1].
-Other people's mechanicals (various) that they haven't brought a tool for.
-Incompetent fettling makes itself known on first subsequent attempt to ride bike^[2].
-Excessive mud/snow/ice clogging things up.
-GPS crashes (buggy routing, loose SD card on eTrex after battery swap).
-Bat flatteries requiring changing.
-Allergic reaction to attack by random flora/fauna^[1].
-Rubbing mudguards, generic loose bolts and rattly things.
-Punctures (including valve problems).
-Crash damage (including attacks by wildlife and inanimate objects) to bike and/or rider.
-Random illness makes itself known mid-ride^[1].
-Headset needing tightening / stem needing straightening.
-Gear cable.
-Broken spoke.
-Cleat problems.
-Non-critical luggage failure (eg. zip).
-Hypothermia^[1].

Very few of these can't be easily dealt with at the roadside.  The most problematic seem to be crash damage, and the various forms of engine trouble.  My main conclusion seems to be that I don't get anywhere near enough punctures...



_{[1] If bio-mechanical failures count...
[2] I've put this in because it's fairly common, but applied common sense means it usually happens within walking distance of home, and not at the start of an important ride.}

[Cudzoziemiec]

By far the most troublesome component for me has been tyres. I've also had brake cables pull out of the lever retention holes because sometime between the mid 80s and mid 90s the design of the blob on the end changed. The only actual ride-ending mechanical was a burst sidewall due to my own teenage ineptitude (badly adjusted brake blocks), but that's outnumbered by car drivers (twice).

[grams]

For me:
- Ripped tyre sidewall caused by dodgy rim tape causing explosive puncture
- Gear cable snapping inside STI shifter
- Losing a chainring bolt (twice, on chainsets that were last disassembled a year plus beforehand)
- Bent hanger and/or rear mech into spokes (sometimes after crash damage, sometimes unexplainable)
- Luggage mounting and bidon cage failures.
- Damaged dynamo cable

I have a whole category of "bolt not sufficiently tightened (or tightened at all, or present) due to rushed last minute home maintenance", but I'm guessing that's not what you're after.

I've never snapped a spoke.

[fd3]

Breaking cranks (x2)
Snapping chain on fixed going downhill (x1)

... I don't think that's standard for most riders and my poor workmanship was contributory to at least one of those.

[Brucey]

most metal parts crack before they break, but it is not always the case that you can see the cracks before they are large enough to cause the part to break.

So when (say) cranks and framesets crack, the cracks can usually be seen before the part is likely to break. But in smaller parts (like spokes) this is not the case. Other parts are hidden from inspection, like steerers and axles.

Thus if you don't want to be let down despite a little TLC, it is sensible to apply a different logic to the purchase of different parts. 

cheers

[ElyDave]

me,

- shifter failure(s) on different bikes
- BB failure - not terminal
- bent rear hangar after fall
- seat bolt/clamp failure (seat kept adopting a nose down attitude)
- valve stem failure due to cooling from use of CO2 (not me, snapped off in a mate's CO2 inflator)
- hub flange failure - others
- explosive tube failure
- light mount bracket failure - fatigue, jury rigged and too lightly constructed - now better.
- idler bolt failure on recumbent - now carry a spare of those
- front mech failure - >10YO, inspection showed fatigue

Absolutely none of those terminal, several inconvenient

[Chris N]

Broken spokes seem to be my most common failure (5 or 6 in the last ten years or so), followed by mudguard issues (usually caused by loose hardware) then saddle/seat post problems (slipping clamps).

Have also had BB bearings give up on me, chainrings come loose, broken/bent mech hangers (one causing the mech to go into the spokes, the other being ripped off by the mech clogging with grass), insufficiently tightened bar and brake lever clamps, saddlebag mount (bagman) failure and electrical faults in dynamo and battery lights.

[mattc]

Inspired by the spare tyre thread.

Apart from punctures, what are the most common mechanical failures you might encounter on a ride? (Let's say in the UK on tarmac roads, on a bike which sees a bit of cleaning and servicing now and again).

I'd say it's well worth reading the articles by LEL mechanics (in Arrivée, and 1 online somewhere? ). They covered this from a pretty objective viewpoint.

[Kim]

I'd say it's well worth reading the articles by LEL mechanics (in Arrivée, and 1 online somewhere? ). They covered this from a pretty objective viewpoint.

Agreed, though it comes with the obvious biases that LEL is a long audax, and therefore not representative of other forms of cycling (eg. heavily loaded, off-road or city riding), and that the mechanics only saw the problems that weren't dealt with by the rider, either at the roadside or through preventative maintenance.

What it shows well is how much of a PITA certain problems (eg. internally routed cables) can be to fix in a hurry.

I'd expect a lot more punctures and things getting bashed while parked in real life.

[ijsbrand]

While commuting? Failing pedals, and slightly bended cranks because either the bike fell, or I and the bike did.



Bike touring has come with a whole other set of problems. Which included a whole frame that got bend after plane transport once.

[Paul H]

Ride ending, train home - snapped handlebar, broken derailleur
Ride changing, continued but not as planned  - crash damaged Ergo
Ride continued - snapped saddle rail, broken hub flange, snapped spoke (Twice), broken mudguard, broken chain link.

It's possible that with periodic examination the crack in the handlebar would have been spotted before it broke , but does anyone do that?
The broken derailleur and damaged ergo could have been avoided by paying more attention to where I was riding 
I don't think I could have done anything to lessen the likelihood of the others, things break.
Cleaning is useful, I've noticed a cracked crank, frame and rack while doing so.   

[Whitedown Man]

Working on the basis that even the most utterly non-mechanically minded (i.e. me) can and should check tyre and brake pad wear regularly, then I’d say cables are the next most likely failure. However, my only DNF-inducing mechanical was when my pump rod snapped in half three hours walk from the next town in the wee small hours on a DIY.

[nobby]

It isn't common but I'm very wary of anything that may buckle a wheel.
I've had it happen twice, 35 years apart, and both times I was bloodied and bruised and the wheels had to be replaced.
First was a pothole (we had potholes in the mid 1970's) and the second was hitting 20mm gravel swept from a farmer's drive while on a Brompton.

[Phil W]

DC levers breaking (most common out of this lot for me)
Cables snapping
Spoke snapping
Frame cracking
Bottom bracket blowout
Crank cracking
Chain snapping
Rear derailleur into wheel
Pump seizing (frame mount and a harsh winter)

Then on my next ride...

[andrew_s]

Things requiring either roadside action or cutting the ride short.
Not counting crash damage or things discovered after investigation at home, such as a cracked crank or a worn out BB.

Spoke broken
Pedal failures
Frame cracked
fallen/falling out bolts
tyre cuts/excessive wear
chain jammed behind crank
broken chain
broken mudguard
broken gear cable
broken crank
split/worn out rim
bent rim (flat spot from a pothole, bad enough to make the brake unusable)
broken handlebar

I ride 36x36, so a broken spoke generally just requires action to stop it flapping about, though I will fix it at the roadside if I'm suitably equipped (i.e. on tour). IIRC, it's 4 in my first machine built wheel, 2 impact damage, 1 at the nipple with 26"/Rohloff/3x, and about 10 that broke in the middle, that I put down to a bad batch of wire at the manufacturer (plus one possible pending failure - I noticed a bend/wiggle in a driveside rear spoke the other day).

The pedal failures were all Eggbeaters, or the Look 4x4 clone. One snapped axle, and several bearing failures that allowed the pedal to slide off the axle. Shortest route home generally, but I ended up carrying a replacement bearing for a bit, before I gave them the sack.

The frame were 3 x gearside dropout breaking where it plugs into the chainstay (fixed under warranty by SJSC), 1 x seat tube/BB shell join in a very old secondhand Mercian, and one cracked round the down tube, starting at the lug point. All were rideable, in a directly home fashion.

[Brucey]

re eggbeater bearings; these are/were of the 'one DU bushing plus one teeny cartridge bearing' type.   If you have a spare cartridge bearing, great, but

a) you can only fit it if you can get the remains of the old one out and
b) if the DU bushing is worn (and that is why the cartridge failed) the same thing will happen again, before too long.

I have seen the same type of bearing layout implemented with no less than three cartridges and one DU bushing, and the pedal still came off the axle, with all three bearings failed. They (of course) cannot share the load unless the DU bushing is in perfect condition.

cheers

[The French Tandem]

Agreed, though it comes with the obvious biases that LEL is a long audax, and therefore not representative of other forms of cycling (eg. heavily loaded, off-road or city riding), and that the mechanics only saw the problems that weren't dealt with by the rider, either at the roadside or through preventative maintenance.

With over 2 million km ridden in 5 days (1500 riders x 1400km), LEL ils a fantastic opportunity to collect statistically significant data on failure rates of various bits. Shame that no zone really took this opportunity.

Regarding the lack of preventive maintenance, yes, the mechanics saw mainly the most poorly maintained bicycles, but failures due to lack of maintenance happen anywhere,  so LEL is not different from any other cycle évent.

[Zed43]

I'm just back from two and a halve weeks of touring in the UK. Rode a lot on national cycle routes, meaning gravel paths and even worse tarmac. Mechanicals (of sorts):

• Arkel Dry-Lite pannier ripped off its attachment strap when I could not avoid going through a hole; Arkel notes "resistance to impact is less than with Arkel's heavy-grade products", HA!
• lost two locking nuts holding the randonneur bag in place
• bolts attaching the rear brake to the frame worked themselves loose, should have used loctite

Before I've had bolts holding the mudguards in place working themselves loose.

[mattc]

Agreed, though it comes with the obvious biases that LEL is a long audax, and therefore not representative of other forms of cycling (eg. heavily loaded, off-road or city riding), and that the mechanics only saw the problems that weren't dealt with by the rider, either at the roadside or through preventative maintenance.

With over 2 million km ridden in 5 days (1500 riders x 1400km), LEL ils a fantastic opportunity to collect statistically significant data on failure rates of various bits. Shame that no zone really took this opportunity.

Well a couple of the mechanics did a reasonable job - see my post a few lines back. To do a more thorough job would take up another volunteer's time, and would not - IMHO - serve humanity (or Audax) all that well.

[The French Tandem]

^^ I'm not blaming anyone! It's just a matter of scientific curiosity. If some volunteer cares to take note of everything mechanics do next time, I think our general knowledge of bicycle failure modes will be enhanced.

[mzjo]

My only ride stopping incidents that I can remember have been
1) a freehub that broke up (either the main hub bearing or the freehub) leaving me with a very wobbly multi-speed fixed. The wheel was a donated second-hand one and I rebuilt it with a new hub and didn't bother investigating the exact cause (crappy cheap hub so it got binned).

2) a hyperglide chain that broke on a club tandem that didn't get used much; meant a slightly complicated walk with a blind stoker.

The club tandems have had a regular history of chains, cassettes, shifters and tyres but most of this is due to lack of maintenance and the rest due to poor communication with those who might be trying to do the maintenance.

Non ride stopping incidents for me have included another hyperglide chain that made it to the finish with a pin out of one sideplate (taught me to never use Shimano chains, especially not scrounged secondhand ones!) and putting a hole in the sidewall of a Pasela because I hadn't readjusted the brakes after swapping out the mtb wheels (different width rims). Otherwise my most common problem is nuts and bolts coming undone (or lost, particularly granny ring chainring bolts) and a couple of times a crank coming loose (for which I always carry the correct tool, 8mm allen key or 14 or 15mm tube spanner depending on the bike). Twice I have had a front brake cable come adrift in the lever (nipple chewed up, vintage Dia Compe aero lever, which has persuaded me to put non-aero levers on the tourer, along with dt  gear levers - no point in looking for trouble!). In the case of the brake cable I did about 150kms on one brake the second time and with the nipple stuck the wrong side of the lever it was a bit of a faff to sort out at home - the first time it happened I ended up untaping the bars and removing the lever, the second time I got a bit lucky with a long-nosed pliars (or pair of pliars, if that is more correct!)