SRAM XX Crankset - GXP BB Play Issues

[Wilkinson4]

So, on my Dekerf I have SRAM XX and a GXP Bottom Bracket. The BB Shell is a custom job with a 67mm width... SRAM recommends 2.5mm spacers on DS and NDS.

My issue is play in the crankset. My LBS ended up using a combo of spacers to finally get rid of the play, but it has tweeked the Q-Factor a bit so DS and NDS are not equal. I have to remove the chainstay wrap to measure accurately but it looks like 2-3mm difference. Maybe not enought to worry about but it kinda bugs me. Anyway, has anyone had an issue with the SRAM XX and GXP BB? I have been thinking about going with a CK BB instead to see if we can get it right. Opinions?

Also, these SRAM Cranks have a funky crank bolt extractor that threads in and we did have issues with that extractor backing out as well. Kind of a PITA.

mIKE

[HillDancer]

...it has tweeked the Q-Factor a bit so DS and NDS are not equal. I have to remove the chainstay wrap to measure accurately...
Measure Q from the center of the seat tube. The drive side stay is often further from the centerline than the other. Example, when spreading the rear triangle to increase axle width, the drive side is the one to bend most.

[oliver1850]

Agree with Hill about measuring from the seat tube.

I don't have any experience with the crank, but I'm guessing they put the shims behind the left arm and didn't check to see if the arms ended up centered. I've ridden bikes with that much offset before without it bothering me, but I would probably move a shim(s) to the drive side to center it. I'd probably check chainline first. If it makes the chainline worse you might be better off with the offset. If your BB shell width is within spec, it seems the only other cause would be something out of spec with the machining on the crank.

[firerescuefin]

Mike, I have a little experience with this BB as well as the CK GXP variant...which is actually the shimano with a spacer kit that addresses width via nylon shims and a springy washer on the drive side the shims/washer is on the crank itself which sounds pretty similar to what they did at the shop. Not sure your issue wouldn't be the same with the CK as with the GXP a



So, on my Dekerf I have SRAM XX and a GXP Bottom Bracket. The BB Shell is a custom job with a 67mm width... SRAM recommends 2.5mm spacers on DS and NDS.

My issue is play in the crankset. My LBS ended up using a combo of spacers to finally get rid of the play, but it has tweeked the Q-Factor a bit so DS and NDS are not equal. I have to remove the chainstay wrap to measure accurately but it looks like 2-3mm difference. Maybe not enought to worry about but it kinda bugs me. Anyway, has anyone had an issue with the SRAM XX and GXP BB? I have been thinking about going with a CK BB instead to see if we can get it right. Opinions?

Also, these SRAM Cranks have a funky crank bolt extractor that threads in and we did have issues with that extractor backing out as well. Kind of a PITA.


mIKE