Bottom Bracket - signs of failure
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HarryTheDog
Guru
- Location
- Basildon Essex
By mentioning cones I take that this is some old type BB ( which I know nothing about) not a BB with just replacement bearings. I quite often get sideways movement on the cranks as the crank needs tightening nothing to do with the BB. ( the joys of a FSA crank)
- Location
- Glasgow
I witnessed @phantasmagoriana ride her bike 100 miles (at least, could have been more) with a well wobbly BB.
mjr
Comfy armchair to one person & a plank to the next
- Location
- mostly Norfolk, sometimes Somerset
[QUOTE 4545289, member: 9609"]The BB on my bike is a cartridge type and as far as i know I won't be able to adjust sideways play.[/QUOTE]
Sometimes they come loose if not properly installed, but that's about all the tightening you can do. Not adjustment as such.
[QUOTE 4545289, member: 9609"]But I am curious if failure is always catastrophic (complete breakdown) or do they just get noisy (like my last one) and would be able to get 20 or 30 mile home.[/QUOTE]
Sometimes they just start to feel rough as you pedal and you can eliminate the wheel hub and chain (edit: by unlinking the chain and trying the BB alone) and everything else (pedal bearings?) as the source of roughness, reducing it to the BB.
Sometimes they come loose if not properly installed, but that's about all the tightening you can do. Not adjustment as such.
[QUOTE 4545289, member: 9609"]But I am curious if failure is always catastrophic (complete breakdown) or do they just get noisy (like my last one) and would be able to get 20 or 30 mile home.[/QUOTE]
Sometimes they just start to feel rough as you pedal and you can eliminate the wheel hub and chain (edit: by unlinking the chain and trying the BB alone) and everything else (pedal bearings?) as the source of roughness, reducing it to the BB.
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Racing roadkill
Guru
It very much depends on the frame material and type of BB as well. An alloy frame with a square taper type BB, will tend to feel more okay, right up until it actually completely fails, than a press fit BB in a Carbon frame, where I personally tend to notice the deterioration much sooner. If the BB is still running freely ( no roughness or graunching ) and there isn't a lot of play, I wouldn't worry too much, until the play is noticeable when you go to unclip ( if your using SPD type pedals) or the bearings are running noticeably roughly. I find It saves a lot of aggravation.
[QUOTE 4545289, member: 9609"]I only mentioned cones in relation to how a wheel feels when you get sideways movement and they need tightened a little. The BB on my bike is a cartridge type and as far as i know I won't be able to adjust sideways play.
I am going to order one to keep on the shelf for when needed.
But I am curious if failure is always catastrophic (complete breakdown) or do they just get noisy (like my last one) and would be able to get 20 or 30 mile home.[/QUOTE]
I once had a rear wheel bearing fail suddenly and catastrophically. I physically could not turn the pedals. As I was only a mile or 2 from home I was able to ride it back slowly by loosening the QR and having the QR spinning in the dropouts, definitely not safe practice.
As for BBs, I have always had Hollowtech ones which have no adjustment. Never had one fail on me but symptoms of wear include noise and a rough feel when you turn them with your fingers. Dirt between the BB and the cranks can produce similar noise so its worth checking that too (my carbon road bike seems very prone to this). I have also mistaken a dirty bottom bracket for gear indexing problems as the noise is very similar.
I am going to order one to keep on the shelf for when needed.
But I am curious if failure is always catastrophic (complete breakdown) or do they just get noisy (like my last one) and would be able to get 20 or 30 mile home.[/QUOTE]
I once had a rear wheel bearing fail suddenly and catastrophically. I physically could not turn the pedals. As I was only a mile or 2 from home I was able to ride it back slowly by loosening the QR and having the QR spinning in the dropouts, definitely not safe practice.
As for BBs, I have always had Hollowtech ones which have no adjustment. Never had one fail on me but symptoms of wear include noise and a rough feel when you turn them with your fingers. Dirt between the BB and the cranks can produce similar noise so its worth checking that too (my carbon road bike seems very prone to this). I have also mistaken a dirty bottom bracket for gear indexing problems as the noise is very similar.
S-Express
Guest
[QUOTE 4545289, member: 9609"]The BB on my bike is a cartridge type and as far as i know I won't be able to adjust sideways play.[/QUOTE]
Sideways play can be adjusted out on cartridge BBs - such movement is not necessarily a sign of failure, just a sign that it may have come slightly loose. Nip it back up and keep riding.
Sideways play can be adjusted out on cartridge BBs - such movement is not necessarily a sign of failure, just a sign that it may have come slightly loose. Nip it back up and keep riding.
jefmcg
Guru
Yeah, I've had a catastrophic failure too. I can't remember if the pedals spun freely or wouldn't turn at all, but the bike was completely unrideable .
It wasn't without warning
. I hadn't had it fixed because the LBS was booked solid for a couple of weeks . Ironically when I limped in with a broken bike, they fixed it while I waited.
It wasn't without warning
. I hadn't had it fixed because the LBS was booked solid for a couple of weeks . Ironically when I limped in with a broken bike, they fixed it while I waited.
andrew_s
Legendary Member
- Location
- Gloucester
Cartridge BBs (square taper). There are also similar cartridge BBs with fatter axles, splined at the ends.
Sideways play in cartridge BBs can only be adjusted out if it's due to a loose lockring (top left).
More usually, it's because the bearings are worn, as was the case with the bottom unit, in which case replacement is all you can do. Usually, you can carry on riding, just putting up with the play, for quite a long time, but occasionally a bit of broken ball, or the ball clip, can jam up the bearing.
Quiz:
Can anyone spot why I thought it worth taking a photo of the old BB after I'd unscrewed it from the frame?
fossyant
Ride It Like You Stole It!
- Location
- South Manchester
As has been said, most square taper cartridge bearings get play well before failure. Mine have always developed play, with a slight knock under pedalling pressure. Time to replace. I've never had one fail completely.
S-Express
Guest
Photography competition?
Dunno, but when I clucked on the photo I got a message saying my phone was infected and an invitation to click a link to fix it. No thanks.
Cartridge BBs (square taper). There are also similar cartridge BBs with fatter axles, splined at the ends.
Sideways play in cartridge BBs can only be adjusted out if it's due to a loose lockring (top left).
More usually, it's because the bearings are worn, as was the case with the bottom unit, in which case replacement is all you can do. Usually, you can carry on riding, just putting up with the play, for quite a long time, but occasionally a bit of broken ball, or the ball clip, can jam up the bearing.
Quiz:
Can anyone spot why I thought it worth taking a photo of the old BB after I'd unscrewed it from the frame?
S-Express
Guest
Incidentally, I get those messages regularly when accessing this site on my phone. Only ever get them on here.
fossyant
Ride It Like You Stole It!
- Location
- South Manchester
[QUOTE 4545701, member: 9609"]wasn't quite sure the way you worded that; are you saying you are happy with a little play but when you feel it pedalling it is time to replace?
On close inspection there is some minor play on this one one (which I don't think was there the last time it had a deep clean (a month ago)) but it is a long way off feeling it whilst pedalling, the bearing itself niether feels or sounds unduly rough. When my last BB failed it basically started grumbling and felt rough.
I have ordered another, it won't take any harm sitting on the shelf.[/QUOTE]
I replace as I get play. It's a warning of it being knackered. Play usually means clunking, and I can't stand a noisy bike.
On close inspection there is some minor play on this one one (which I don't think was there the last time it had a deep clean (a month ago)) but it is a long way off feeling it whilst pedalling, the bearing itself niether feels or sounds unduly rough. When my last BB failed it basically started grumbling and felt rough.
I have ordered another, it won't take any harm sitting on the shelf.[/QUOTE]
I replace as I get play. It's a warning of it being knackered. Play usually means clunking, and I can't stand a noisy bike.
