Discussion
Friend of mine has a Felt F4130. nice bike, but he's been having trouble with the bottom bracket.
It was clunking for a while, so he took it in and and someone in the shop tightened it. But a couple of weeks later it was loose again.
Had it in for a service and the very next day one of the crank arms came off as he was pedalling. He was very lucky, bearing in mind he was on a busy London road, that he didn't come off completely and fall in front of a car. Though it was serious, him telling the story and mentioning how he quickly had to get to the side of the road with his foot still clipped in to the pedal and the crank arm attached to that does make me smile.
Now, the shop involved in the service were very apologetic and have offered to replace the entire bottom bracket and cranks for free, but it does seem to me that these BB30 bottom brackets are more trouble than they're worth.
I'd never heard of them before - and he'd been given no advice when he bought the bike about having to tighten it periodically, but it seems like a flawed design. Most bottom brackets don't get touched for years.
Not really sure where I'm going with this other than, do you think these will be phased out? Improved? Something else?
It was clunking for a while, so he took it in and and someone in the shop tightened it. But a couple of weeks later it was loose again.
Had it in for a service and the very next day one of the crank arms came off as he was pedalling. He was very lucky, bearing in mind he was on a busy London road, that he didn't come off completely and fall in front of a car. Though it was serious, him telling the story and mentioning how he quickly had to get to the side of the road with his foot still clipped in to the pedal and the crank arm attached to that does make me smile.
Now, the shop involved in the service were very apologetic and have offered to replace the entire bottom bracket and cranks for free, but it does seem to me that these BB30 bottom brackets are more trouble than they're worth.
I'd never heard of them before - and he'd been given no advice when he bought the bike about having to tighten it periodically, but it seems like a flawed design. Most bottom brackets don't get touched for years.
Not really sure where I'm going with this other than, do you think these will be phased out? Improved? Something else?
I have a BB30 on my Cannondale. I've had no issues with it in the 15 or so months I've had the bike. A couple of occasions ive started to get creeks I've immediately assumed it was the BB but on both occasions it was actually my pedal/cleat.
I had no idea you were supposed to periodically tighten them. I've not touched mine in all the time I've had it.
I don't think the crank arm falling off was a fault of the BB, more a bit of negligent spanner work by the LBS. Which I dare say is why they were so quick to throw a new BB and chainset at your friend.
There does seem to be a lot of bad press for BB30 though.
I had no idea you were supposed to periodically tighten them. I've not touched mine in all the time I've had it.
I don't think the crank arm falling off was a fault of the BB, more a bit of negligent spanner work by the LBS. Which I dare say is why they were so quick to throw a new BB and chainset at your friend.
There does seem to be a lot of bad press for BB30 though.
As I say I had no previous knowledge of them.
But when he was looking for someone to replace it - the splines looked like they'd rounded off - the bike (supplying) shop said that it wasn't a failure of the part and the damage would have happened when the crank arm came off. Reasonable I suppose. It was at this point they mentioned that it should be re-torqued every 2,000 miles or so or you risk it coming loose.
As it is, I also believe that the servicing bike shop is to blame here.
My mate has now bought a torque wrench so that he can keep an eye on it.
But when he was looking for someone to replace it - the splines looked like they'd rounded off - the bike (supplying) shop said that it wasn't a failure of the part and the damage would have happened when the crank arm came off. Reasonable I suppose. It was at this point they mentioned that it should be re-torqued every 2,000 miles or so or you risk it coming loose.
As it is, I also believe that the servicing bike shop is to blame here.
My mate has now bought a torque wrench so that he can keep an eye on it.
The crank arm fell off my new boardman but as I'd signed for the bike unbuilt then I guess I only have myself to blame for not checking that the pre installed crank was torqued up. Once it had 40Nm on it it never budged again.
We've got a new Specialized, Cannondale and the Boardman this year and apart from the above they've all been great. My previous bikes have all been Hollowtech up to now but I quite like the BB30 now. We do a lot of cyclocross and also change gearing quite a bit and they've always gone together and come apart nicely. I like the way that the crank bolt acts as a puller to drive the arm off the crank. Once its torque down it certainly needs a fair torque to get it off again.
Has anyone double checked the installation diagrams in the manual to ensure he has the correct shims, covers and wavey spring in place? If the wavey spring is crushed flat then it will absorb the clamping force before the crank arm is seated home.
We've got a new Specialized, Cannondale and the Boardman this year and apart from the above they've all been great. My previous bikes have all been Hollowtech up to now but I quite like the BB30 now. We do a lot of cyclocross and also change gearing quite a bit and they've always gone together and come apart nicely. I like the way that the crank bolt acts as a puller to drive the arm off the crank. Once its torque down it certainly needs a fair torque to get it off again.
Has anyone double checked the installation diagrams in the manual to ensure he has the correct shims, covers and wavey spring in place? If the wavey spring is crushed flat then it will absorb the clamping force before the crank arm is seated home.
Edited by Bobley on Tuesday 26th November 13:20
Bobley said:
The crank arm fell off my new boardman but as I'd signed for the bike unbuilt then I guess I only have myself to blame for not checking that the pre installed crank was torqued up. Once it had 40Nm on it it never budged again.
We've got a new Specialized, Cannondale and the Boardman this year and apart from the above they've all been great. My previous bikes have all been Hollowtech up to now but I quite like the BB30 now. We do a lot of cyclocross and also change gearing quite a bit and they've always gone together and come apart nicely. I like the way that the crank bolt acts as a puller to drive the arm off the crank. Once its torque down it certainly needs a fair torque to get it off again.
Have you check the installation diagrams in the manual to ensure you have the correct shims, covers and wavey spring in place? If you crush the wavey spring flat then this will absorb the clamping force before the crank arm is seated home.
As I say, not my bike.We've got a new Specialized, Cannondale and the Boardman this year and apart from the above they've all been great. My previous bikes have all been Hollowtech up to now but I quite like the BB30 now. We do a lot of cyclocross and also change gearing quite a bit and they've always gone together and come apart nicely. I like the way that the crank bolt acts as a puller to drive the arm off the crank. Once its torque down it certainly needs a fair torque to get it off again.
Have you check the installation diagrams in the manual to ensure you have the correct shims, covers and wavey spring in place? If you crush the wavey spring flat then this will absorb the clamping force before the crank arm is seated home.
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