SRAM gxp BB bearings gone

[wearwell]

SRAM gxp is a very neat design - not least the self-contained crank extracting set up. And it's obviously very light.
But one bearing has gone already. Is this common?

I doubt I've done 2k miles on this bike from new. Have done very many more miles with various shimano BBs which seem to outlast the bikes themselves.

Can one replace just the bearing or is it a new BB?
Not expensive but still a PITA!

[Keezx]

Which bearing is gone?

[Brucey]

SRAM gxp is a very neat design - not least the self-contained crank extracting set up. And it's obviously very light.
But one bearing has gone already. Is this common?

I doubt I've done 2k miles on this bike from new. Have done very many more miles with various shimano BBs which seem to outlast the bikes themselves.

Can one replace just the bearing or is it a new BB?
Not expensive but still a PITA!

if you read SRAM's service instructions they say to regrease GXP bearings once ever few hundred miles and additionally to that whenever the bearings have seen the worst kind of weather. I think you should be able to replace a bearing or two (in a cup perhaps) and get going again; these bearings do fail and fail often, so they are available.

cheers

[wearwell]

Which bearing is gone?

Near side

if you read SRAM's service instructions they say to regrease GXP bearings once ever few hundred miles and additionally to that whenever the bearings have seen the worst kind of weather. I think you should be able to replace a bearing or two (in a cup perhaps) and get going again; these bearings do fail and fail often, so they are available.

Really? I see no instructions on the installation guide. In any case they are supposed to be sealed bearings. But lubrication doesn't seem to be the prob - they are clean with plenty of the original grease still in evidence.

I'll get another BB they are not pricey. I'm planning to replace the whole SRAM APEX set up as it's been a PITA from day one, but trying to get my monies worth before I shell out another few hundred quid!

[Brucey]

if the bearing internals are clean they they shouldn't be worn. Are you sure you have set the bearing preload correctly?

Re servicing the advice here on p25 is typical for recent SRAM BBs

https://sram-cdn-pull-zone-gsdesign.netdna-ssl.com/cdn/farfuture/YjkhMdAWX5nhj3hY8wwPA3Aucz1JjRnlCvzTmjf9Hyw/mtime:1372788147/sites/default/files/techdocs/my10-sram-tech-manual-rev-a.pdf

so yes, you do need to regrease them as I previously advised.

cheers

[wearwell]

if the bearing internals are clean they they shouldn't be worn. Are you sure you have set the bearing preload correctly?

Re servicing the advice here on p25 is typical for recent SRAM BBs

https://sram-cdn-pull-zone-gsdesign.netdna-ssl.com/cdn/farfuture/YjkhMdAWX5nhj3hY8wwPA3Aucz1JjRnlCvzTmjf9Hyw/mtime:1372788147/sites/default/files/techdocs/my10-sram-tech-manual-rev-a.pdf

so yes, you do need to regrease them as I previously advised.

cheers

Right.
Bearing preload was set by bike supplier (Spa Cycles)
It says one should re-grease the bearings immediately after any exposure to water. This means they are totally unsuited to anything but fair-weather cycling conditions. Glad I've got that sorted! The sooner I dump SRAM APEX and hub, the better.
All the shimano BBs I've had have been sealed for life and needed no service at all - except to take the whole unit out now and again to make sure it hasn't seized up in the bottom bracket

[wearwell]

Had it all apart. Easy to do. The seals come off easily (too easily?) but the grease inside looked OK. So the bearing has failed in normal moderate use, not for any other reason.
It's usable but a bit graunchy and I've ordered a replacement.
Are there better alternative BB units which would take the SRAM pedals?

[Brucey]

....It says one should re-grease the bearings immediately after any exposure to water. This means they are totally unsuited to anything but fair-weather cycling conditions....

correct... but then the current generation of shimano H-II bottom brackets are similarly constructed (seal wise), fail as quickly without maintenance etc, only shimano are deluded enough to say 'no user serviceable parts inside'.... so go figure...

You can buy new sram gxp bearings and cups for less than £15 . You need a GXP compatible bearing set because (say) a shimano cup set won't fit your cranks. Hope make a nicer (more durable) set of cups/bearings that (together with a converter set, purchase separately) will work with a GXP crankset.

When you install the new cups you need to torque the crank bolts carefully as per the instructions, so that the LH bearing is trapped against the shoulder on the spindle. If you don't do this everything will wear and it will seem as if the bearing is worn whether it is or it isn't. If the wear is bad enough the spindle will be damaged and that will finish the crankset.

In all fairness I can't think of a crankset type where you could expect to be able to ride it 2000 miles without it being a good idea to have the crankbolts retorqued to be sure that nothing was working loose. [This is why most bike shops offer a free service after a few weeks.] In the case of a GXP unit it ought to be regreased several times in that mileage if you follow the service instructions.

Not fit for purpose? Well that is how it is these days, lighter, stiffer, 'racing inspired', more gears.... and less durability...??

You can still buy square taper BBs and matching cranks. You can still buy 9s transmissions that last a fair bit longer than 10s (let alone 11s) so you don't have to buy this stuff if you don't want to.

cheers

[tim-b]

Hi
The Gussett ext 24 has a good name with MTBers, and they now do a SRAM version
I think that the bearings are designed to be replaceable in these, but ask your dealer to be sure
Regards
tim-b

[wearwell]

Thanks for all the info.
Now I see how it works the GXP does look doomed to fail regularly as the axle is tight fixed to just one inner race of the near side bearing, which is going to take a lot of hammer.
On the other hand it's very quick and easy to dismantle/replace and not expensive (at the cheap end at least). Also in spite of lack of maintenance the flimsy seals had not failed and the original grease was still in place.

[reohn2]

Hi
The Gussett ext 24 has a good name with MTBers, and they now do a SRAM version
I think that the bearings are designed to be replaceable in these, but ask your dealer to be sure
Regards
tim-b

Thanks for the heads up.
Whilst checking it out I came across this:- http://s383075164.e-shop.info/shop/arti ... d%3D707%26
I wondered if it's the answer to the EBB problem,anyone heard about or tried them?
PS,Mine's a young Deore BB51 which though keeping an eye on,I'll not be surprised at premature failure,as EBB's are a real dogs dinner of an idea IMHO

[Brucey]

roller bearings are stronger and more durable but only if they are well aligned (to a higher tolerance than ball bearings) and the seals keep the water out.

Since all these BBs fail because the water gets in and furthermore the alignment is often a bit suspect (which is why shimano bearings sit on plastic collars and beds of retaining compound) then simply fitting roller bearings is kind of treating the symptoms not the cause. Unless the seals are many times better than those fitted to alternate units and the alignment is perfect I'd expect the life to perhaps be shorter if anything....

BTW the GXP unit does use a single bearing on the LH side to withstand the lateral loads. If this doesn't last long (and there is no sign of water ingress) then I'd suspect that the alignment is perhaps not quite good enough.

cheers

[beardy]

Those tapered bearings would allow you to get the bearings out very rapidly and clean and grease them very easily.

[reohn2]

roller bearings are stronger and more durable but only if they are well aligned (to a higher tolerance than ball bearings) and the seals keep the water out.

Since all these BBs fail because the water gets in and furthermore the alignment is often a bit suspect (which is why shimano bearings sit on plastic collars and beds of retaining compound) then simply fitting roller bearings is kind of treating the symptoms not the cause. Unless the seals are many times better than those fitted to alternate units and the alignment is perfect I'd expect the life to perhaps be shorter if anything....

BTW the GXP unit does use a single bearing on the LH side to withstand the lateral loads. If this doesn't last long (and there is no sign of water ingress) then I'd suspect that the alignment is perhaps not quite good enough.

cheers

Thanks for that I'll take your word for it.
Going off reviews it'll probably be this when mine expires:- http://s383075164.e-shop.info/shop/arti ... 705.004%26
PS, they come in pretty colours too

[pliptrot]

So, just to be clear; if you ride in the rain once, you will need to regrease the bottom bracket bearings. This is for equipment sold in the UK. Really?