GXP BB Service

seanorawe

So

Following on from a previous post, ive narrowed everything doen to my sram GXP BB needing serviced, to get rid of some noise. THe BB is 6 months old

IS it best to take off the BB cups and clean the re grease cups and also the threads in the frame, then put it all back together?

Or

Do I need to get into the cartridge itself and try and clean and grease the balls? IF so, can anyone recommend a guide to follow for the process? Im afraid of breaking the seal that protects the balls.

nicklouse

remove and replace if the cups are not just lose or the retaining bolt not tight.

keezx

seanorawe wrote:

Or

Do I need to get into the cartridge itself and try and clean and grease the balls? IF so, can anyone recommend a guide to follow for the process? Im afraid of breaking the seal that protects the balls.

Take the cups+bearings out of the frame and put them in container with degreaser.
After flushing out all junk inject fresh grease (from inside, seals are only on outside)
Noises can also come from the left side as the bearing inside is 22,2 mm and the axle is 22,0 mm.
The newer GXP BB's have all this 22,2 mm.
I fill the gap with Loctite or something like that > noise gone.

seanorawe

This bb came with my bike bought from planet x about 6 months ago. But I don't have a caliper to measure the bottom and axle. What's the purpose of the loctite. Will grease do the same job ?

keezx

No, grease won't help, it needs something solid to fill the little gap.

seanorawe

Keezx wrote:

No, grease won't help, it needs something solid to fill the little gap.

Where do you put the loctite?

svetty

seanorawe wrote:

Keezx wrote:

No, grease won't help, it needs something solid to fill the little gap.

Where do you put the loctite?

Exactly! Funnily enough SRAM make no mention of Loctite in their servicing instructions.........

If you remove the crank and just turn the bearings by hand you will feel if they are smooth or not. If so just regrease the spindle and re-insert. If they are rough then IMO re-greasing achieves little - just replace.

captain_tiara

Ha, timely thread!

Recently turned into time to replace GXP BB. Had the groupset [Rival] on what is now my winter bike since 2009. I've been through a couple of steel & a couple of ceramic BB's in that time.

So I bought one of these GXP Team BB's, which it would seem is what you can get now - or Blackbox Ceramic. I've worked out that @ £20 for the steel vs £100 for the ceramic I can't really justify the ceramic's cost. They might get me, just, through 2 winters, but at 1/5th of the cost & no real discernable difference you can afford 5 steel ones.......

Anyway, I've had no problems in the past with installing sram/truative GXP BB's. In it goes, tighten it up & off you go.

The "improved" gutter seals on the "Team" version are a crock of sh*te. Totally not a seal on the non-drive side. Bearings are really bad, rough, worse than the ceramic ones coming out after 2 years.

And I couldn't actually tighten the bolt up without pinching the bearings & stopping the cranks from turning. Tried every permutation with the spacers for this 68/73 utilitarian version [which incidentally you didn't need before...]. Utter fail.

Luckily I kept 2 old sets in the spares box 1 ceramic 1 steel. I never really entertained the thought of replacing the bearings cos a whole new BB is £20ish. But you can't get a non "Team" GXP BB since they "evolved".

Luckily I picked it up from Halford's so with the really bad bearings managed to get a refund.


So, knocked out the sealed bearings, checked the difference between drive & non-drive side, did some interweb research & the best result is http://www.airebearings.co.uk/Bike-bear ... 20bearings

So now you can replace your GXP bearings for under a tenner.

keezx

Svetty wrote:

seanorawe wrote:

Keezx wrote:

No, grease won't help, it needs something solid to fill the little gap.

Where do you put the loctite?

Exactly! Funnily enough SRAM make no mention of Loctite in their servicing instructions.........

.

Well , sometimes things are not made as they should be an you'll have to work out how to make them working properly.
If SRAM had not changed the left bearing to a , as I suspect , cheaper one there wouln't be a problem.
It is a well known fact that the later GXP BB's do not fit perfect at the LH axle and will develop creaking noises.
There is a small gap axle-LH bearing and this must be filled with somthing suitable, as Loctite...
The crankbolt cannot be torqued to a crazy value as it's light alloy.
put loctite on the 22 mm part of the axle before fixing the cranks in the BB.

Changing the bearings to good fitting ones is even better......

captain_tiara

I lied.

It is exactly a tenner, delivered!

seanorawe

I took the BB out yesterday. and gave the whole thing a good thorough clean and greased her up with plenty of marine grease. Commuted to work today and its running smooth. I did have to pop out the little bearing cover on the drive side as the left side just falls out off on its own. IT was dry as a bone inside. The whole BB was dry and not a spot of grease on it, so Im thinking Planet X either used shit grease, or I need to be more careful washing the bike, or both!

Anyway, its now running smooth, as soon as it happens again ill replace the BB. as the BB tool I used was not gentle on the shell.

seanorawe

Captain Tiara wrote:

I lied.

It is exactly a tenner, delivered!

That whole process sounds scary for a learning home mechanic like me.