Play in GXP bottom bracket

YateleyChap

My GXP BB has developed 1-2mm of play which I'm struggling to eliminate. I have a 68mm BB shell with 2.5mm spacers on either side of the bb, SRAM X7 triple ring (which the GXP BB came with). I've tried a variety of different spacer combinations including adding additional spacers on either side to see if that helps, and the crank arms are done up as tight as possible. The bearings themselves are fine as well. It's 6 months old and I'd say it's had fairly heavy usage as I'm a 14 stone fatty and ride at least 3-4 times a week for about 2 hours each time.

Reading through other posts the consensus seems to be that GXP BBs are pretty lousy and don't last long, but before I invest in any new bling I'm interested to know if there's anything else I could try to get rid of the issue?

If it's game over, then has anyone successfully changed to a Hope BB with the (hugely overpriced) GXP adapter with SRAM cranks without any play or other issues?

Cheers

The Rookie

Which way is the play? Axial (along the line of the axle which could be a preload issue) or radial (at 90 degrees to the axle) which is not a preload issue but a bearing issue.

On shimano you use 2 spacers drive side and one non drive, 2 of the 3 spacers widen the shell to an effective 73mm and the last is in place of any BB mounted device (e.g. E type mech or Stinger), not sure about GXP.

YateleyChap

I'd say the play is radial, I can't move or slide the crank left to right along its axle and out of the bb shell as such, but if I hold both crank arms in line with the seat tube (so 90 degs to the ground) then the play is evident as the arms move towards and away from the frame (most noticeably at the pedals as they're furthest away from the axle).

The GXP manual from SRAM states that for a 68mm mtb bb shell one 2.5mm spacer is required on either side to take it to an effective 73mm. I don't think any extra spacers are needed to replace mounted devices, although I have simulated this by using a variety of different spacer combinations to try to eliminate the play myself with no success.

I think your point about radial play being related to the bearings is most likely, I'll strip it down again and take another look at the bearings themselves. Unfortunately they are semi-sealed units so there's little I can do if that is the cause. They seemed fine when I had it all in bits yesterday and they're still moving smoothly and not gritty in any way. Maybe I'll just keep using it until it breaks then invest in some new bling!?

Thanks for your help, much appreciated :-)

supersonic

These can take quite a bit of tightening up ie the one key retention system. My Noir chainset uses a little washer over the axle too.

nicklouse

Adding spacers to the BB can only do one thing kill your bearings. The GXP set up uses no preload.

Repack the bearings with grease and if that does not work then cups/bearings needed.

jonnym5

I've found that changing from the older black squarer shouldered GXP to the newer grey one has left me with a bit of play.

Googling around seems to suggest it's quite common. I tried two brand new BBs on the old chainset, a new chainset with new bb and it still had play. That was with torquing it up properly too.

YateleyChap

Cheers for all the input guys, seems to me these are pretty poor BBs. I've stripped it again to take another look and the bearings are shot (no doubt prematurely caused by the play) so I think I'll look into getting something decent like the Hope BB with the GXP conversion kit. There are a few deals out there at the mo so it's not too pricey and it'll also match my headset and stem.