Press Fit Bottom Bracket Problem - Help

[dev null]

I have the following problem with my son's Giant XTC frame/bottom bracket.  It seems that the bracket came loose on the drive side, and the whole thing now has too much play to press fit it back.  What do I do?  Don't want to scrap the frame.

 

BTW, it is a normal Shimano Press Fit BB with plastic shells.

[David Marshall]

It is a common problem, usually on the non drive side.  You can try to press the BB into the frame with a shim made from a strip of thin aluminium from an imported beer can.  Before the BB is fully home trim any excess material with a sharp blade.

[dev null]

Thanks Dave

 

It's a pity that nobody as yet have manufactured aluminium inserts that can be epoxied into the carbon shell to help with this problem.

 

I hate press-fit bottom brackets.

[SCD]

the plastic ones have a limited life span. Rather replace. It's not very expensive. R200-300 for the BB, a threaded rod, washers and nuts for a make shift bearing press.

[dev null]

Yes, but I have a suspicion that the bracket on the drive side have been spinning in the shell, wearing it out a bit by a few thou.  Thus the talk of some sort of shim or whatever.

 

A permanent solution would be better.  I don't know if the Chris King BB sorts this issue out.

[BogusOne]

If its a carbon frame it can be built up so the bearing fits snugly again. If its a alu frame id go for David's suggestion.

 

[dev null]

Carbon frame.  Do one get a reamer to ream the shell to spec after building it up again?

[nick18]

Have a look here, an aluminium pressfit bob with Enduro bearings:

 

http://www.rushsports.co.za/collections/bottom-brackets

[Tony datoy]

Why not try a warrantee claim, push Giant to replace the frame.

T

[David Marshall]

 

I hate press-fit bottom brackets.

 

They are such a step back after the outboard cup - GXP type.  All in the name of weight saving.  A larger diameter tube made thinner.

 

I used to service Alex Harris' training bike (aluminium).  That man could a shred a bb bearing in days.  The non drive side used to go first.  I hit on the idea of just replacing the one side at a time.  Tried to use an old RHS cup in the left but no chance - even when a new cup would sit firm.  Eventually the frame wore on the left to the extent that we had to shim.

[dev null]

Why not try a warrantee claim, push Giant to replace the frame.

T

 

Looking at that option first, but I have an idea Giant will say it is normal wear and tear. Next up is the fix suggested by BogusOne.  Else I will have to get inventive.

[dev null]

Currently looking at this option to help strengthen this weak area on the XTC Advanced SL frame.

 

http://wheelsmfg.com/bottom-brackets/bb86-92/bb86-92-bottom-brackets/bb86-92-outboard-angular-contact-bb-for-24mm-shimano-cranks-black.html

[dev null]

Where can I get carbon fibre cloth and resin to fix the bottom bracket shell.  I decided that either the wheels manufacturing or the enduro BB is the way to go, but I must still build up the carbon fibre that was worn away.

 

I am in the Helderberg basin BTW, for those that do not know where Strand is.

[raptor-22]

Amt composites in maitland

[The MTBer]

I took my XTC Carbon in for a new bb (GXP Press fit). At collection my LBS said that when they removed the bb the Aluminum sleeve also came out with the bb (and it is not supposed to come out of the carbon). The Alu sleeve is where you press on the cups, that way you don't press the direct into the carbon (I think). They also said it may be a warrenty claim, because the chances that it will come loose in the near future is more that 90% and it will then just make everything bigger, and bigger means the normal bb won't fit.

 

Anyone had similar experiences? Is it really a possible warrenty claim?

[dev null]

If you are the original owner, try warranty claim first. Then, when you get the new frame, immediately put in a Wheels Manufacturing or Enduro BB where the 2 halves screw into each other.

 

If the claim is not an option, get the carbon built up again and attempt the BB options above. I had the same problem, as explained in this thread, and the Enduro BB option sorted that out.

 

The problem is that the Giant carbon BB shells has too much flex. When you pedal, it flexes and starts rubbing on the interface with the standard pressfit BBs, eventually causing the carbon to wear away.

 

Good luck anyway.