Sigh ... bottom bracket going again?
Discussion
Boardman MHT 8.9 bought in April, done about 1000 miles on it.
Although I can feel no play in it, theCrankshaft main bearing Bottom bracket has started making a 'cracking' noise on each pedal stroke that resonates through the frame. Presumably the bearings are starting to break up? Started to do it on Friday I ignored it hoping it might go away by itself but this morning its well and truly creaking.
By 2000 miles the bottom bracket on my last bike a Giant Talon was on its way out with play evident, but this one is starting to show signs of failure after only 1000 miles. Do they really only last for such a short length of time? Replacement should be covered by Halfords under the warranty? Any one know what type of bearing it is?
Although I can feel no play in it, the
By 2000 miles the bottom bracket on my last bike a Giant Talon was on its way out with play evident, but this one is starting to show signs of failure after only 1000 miles. Do they really only last for such a short length of time? Replacement should be covered by Halfords under the warranty? Any one know what type of bearing it is?
I'll try and trace a Hope replacement then and probably do it myself. I'll let you know how I get on 
I just looked up the spec and it might have an FSA megaexo BB. In my experience FSA BBs are shockingly bad.
FSA megaexo and Shimano Hollowtech II BBs are directly compatible, so you could swap it for a Shimano one.
The Shimano BBs aren't that bad but as mentioned, Hope are known to last significantly longer.
FSA megaexo and Shimano Hollowtech II BBs are directly compatible, so you could swap it for a Shimano one.
The Shimano BBs aren't that bad but as mentioned, Hope are known to last significantly longer.
Treb0r said:
I just looked up the spec and it might have an FSA megaexo BB. In my experience FSA BBs are shockingly bad
Yes it has one of those fitted. I took the bike into Halfords, they will replace it under the warranty but (as usual) there is a catch ... they can't do it until Thursday week.... There is still no play in the crank, but the bearing is making a right racket. Do you recon I'll be able to creak on for a week, or is the bearing likely to disintegrate into many bits stranding me? The weather is far to good to be off the bike at the moment. I might ask Halfords to get the bearing in, and I'll do it myself. GSE said:
Do you recon I'll be able to creak on for a week, or is the bearing likely to disintegrate into many bits stranding me?
It's very rare that the bearing will disintegrate to the point of being unrideable, however with the BB30 system where the bearing sits directly in the frame my main concern would be that any movement in the bearing could be damaging the BB shell in your frame. I've seen it before where a frame was rendered scrap due to to an ovalised BB shell.I’ve just looked at the FSA megaexo BB you have on your bike. It’s actually threaded already by the looks of it. In which case the loud click you’re hearing is more than likely down to the cups starting to loosen. Get a BB tool on it and torque the cups up to 40Nm. That should help. I have a power spline cartridge BB on my old Boardman MX Comp, and that clicks like a good’un when it’s ‘settling’ after a new one goes in, on old threads. I had to re torque the last one 3 times until it settled, and stopped clicking.
GOATever said:
I replaced the PF 30 on my old Boardman Pro Carbon with this
It’s a PF30 to HT2 threaded outboard type adaptor. I’ve had no issues ever since.
I am under the impression OP has a BB30 system rather than PF30, so that adaptor wouldn't work. It’s a PF30 to HT2 threaded outboard type adaptor. I’ve had no issues ever since.
Good choice though, wheels MFG make some lovely components, Praxis Works are another top quality brand who do similar stuff
Just re-read and realised OP has a mega exo system, which is just their version of an outboard bearing (a la HT2, X type, GXP etc)
OP feel free to keep riding it if you can put up with the noise. It almost certainly won't leave you stranded and the only thing it'll damage more is itself, which is fine as it's destined for the scrap heap already anyway.
If you want to upgrade then in theory you need an FSA specific item, such as that available from wheels MFG, however in practise you should be able to make it work with one of the other standard sized (24 mm spindle) bottom brackets, e.g. hope. The difference is that most outboard systems use a 24 mm spindle, but FSA use one which is a tiny bit larger; ~ 24.07 mm, but with a bit of persuasion it probably would fit.
OP feel free to keep riding it if you can put up with the noise. It almost certainly won't leave you stranded and the only thing it'll damage more is itself, which is fine as it's destined for the scrap heap already anyway.
If you want to upgrade then in theory you need an FSA specific item, such as that available from wheels MFG, however in practise you should be able to make it work with one of the other standard sized (24 mm spindle) bottom brackets, e.g. hope. The difference is that most outboard systems use a 24 mm spindle, but FSA use one which is a tiny bit larger; ~ 24.07 mm, but with a bit of persuasion it probably would fit.
Gareth79 said:
Do check everything else first before replacing the BB. I just built up a new bike (from a 2nd hand frame) and had a new BB pressed in. It creaked when standing in the pedals but after some head scratching I tightened the rear QR skewer and it stopped!
QR skewers are a good source of creaks, as are spoke crossing points, seat rails, pedals etc etc etc. But I think the OP was complaining of the loud click you get from a threaded BB when the cups come a little loose.Generic Shimano-like one on my hardtail only lasted about 700 miles before it needed attention. Overdoing the preload on the bearings (when the cranks are being (re)fitted) is a very common cause of premature wear, it doesn't need to be tight at all.
I thought about a Hope or similar but when a Deore BB is a tenner on CRC you'd have to get through a lot of them for it to make financial sense.
I thought about a Hope or similar but when a Deore BB is a tenner on CRC you'd have to get through a lot of them for it to make financial sense.
shouldbworking said:
Whilst fsa megaexo bbs are rubbish, you haven't said what you have done to prove it's that making the noise.
Bike frames carry sound rather well. Have you taken the chain off and spun the cranks in a stand to pin down the cause?
I've done exactly this. The noises are definitely coming from the BB, with the chain off there is a regular scratching/cracking noise, like ball bearings rattling about in a jam jar, each time you rotate the pedal. Under load, when riding the bike, occasionally there is a loud click coming from the left hand crank. Yet I can feel no play through the crank arms when moved by hand. Also the noises seem to be amplified through the frame as if they are coming from the head set! Aside from the noise issues, the bike is still riding fine, did 110 miles on it this week.Bike frames carry sound rather well. Have you taken the chain off and spun the cranks in a stand to pin down the cause?
I took it to Halfords they've agreed to replace the bearing under the warranty next week. I'm relatively new to biking and from what I've found out it's not unusual for BB's to fail at this mileage. Since I switched to commuting by bike, instead of using the car, I like to compare the pro's and con's of both methods of transport. I can run my Fiesta for 6 months and 6000 miles without requiring surgery, I was kind of hoping that the bike would be the same! I'm not overly concerned about the problem, interested in the technology as well. When Halfords replace the duff BB, I'll ask to take it away and I might cut it open on the lathe at work and see what's going on
At £40 a go, based on my annual mileage I will have to spend an extra (unplanned) £120 per year on BB's - might as well get Halfords to do it under the warranty
Edited by anonymous-user on Friday 19th July 19:07
GSE said:
When Halfords replace the duff BB, I'll ask to take it away and I might cut it open on the lathe at work and see what's going on
It’s an aluminium cup with a bearing in it, with a seal over the top. You can just knock out the bearings and replace them for a couple of quid, if you can be bothered that is.The green tube is just that, a bit of plastic tube to keep crap out.
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