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Play between Truvativ GXP bottom bracket and crank spindle?

19K views 11 replies 7 participants last post by  wschruba 
#1 ·
So I have a new have a CX setup with about 200mi on it. A roulleur crank and GXP bottom bracket. The other day I noticed some play in the crank while standing on the pedals. So I turned around and went home. I noticed there was some play in the crank when I put it on the stand and grabbed both arms with my hands and torqued it. I proceeded to disassemble things and found the the source was the non drive side bearing. It turns very smooth but the problem I see is that the crank spindle doesn't fit tight against the inner race. I happen to have a second truvativ crank and it fits the same way on that one. The drive side seats much tighter with no wiggle room.

Is this typical of GXP cranks or do you think the bottom bracket is out of it's range of tolerance? Any other ideas?

The fixing bolt never came loose, just play in the crank/bearing interface. Unfortunatly I bought the bike off ebay so I'm own my own to solve this one. Thanks in advance.
 
#3 ·
I've recently replaced my damaged crankset and bottom bracket with a new GXP one at the LBS. I also noticed a little play (i can pull crankset a little from side to side, maybe 1-2 mm, or rock it frontwards or backwards). I did not take it apart so i do not know if it is a similar case.

The fixing bolt is torqued correctly and i trust my LBS as they do quality work. The mech functions as it should but i am not sure if this play is acceptable and if i should somehow fix that play or take the bike to the LBS. What did you end up doing?
 
#4 ·
The trick to install Truvativ/Sram cranksets is to actually read and follow the directions. If its not installed properly, there will be play. Regardless of who installs the crank. LBS included.

http://www.sram.com/_media/techdocs/95-6115-003-000.pdf

Assemble the left crank arm onto the bottom bracket spindle using an 8 mm hex
and torque to 48-54 N∙m (425-478 in-lb).
Check the assembly for play by rocking the crank arms back and forth away from frame.
If the crank moves, tighten crank arm bolt until no play is detected. If maximum torque
of 54 N∙m (478 in-lb) has been achieved, remove the crank arm from the spindle, apply
additional grease and repeat installation proceedures until play is eliminated.
 
#5 ·
the play is from the bearing itself. there is an inner race fixed to the bearing to take a few mm's. the non drive side of the spindle is slightly smaller than the drive side. this is the cause of the play. switch to the new king gxp and all your problems will be solved.
 
#7 · (Edited)
Thank you for informed comments.
Funny thing is, i was reading the GXP manual as you posted.
RTFM acronym is so timeless :)

p.s. Yet there are situations (and i am not implying that this is one) when the manuals ask for something in a "just do it" manner, like "if you are depressed just take a year off and travel the globe," hehe.
 
#9 ·
I'm actually having this issue with a brand new crankset and BB right now. I've installed and maintained these many times before, but I just can't get this one right. Would a thicker grease be recommended? I'm using the green Park Polylube grease right now, and while more grease creates less play, I've literally got the non-drive side BB cup packed full of grease and more grease on the spindle...still has play.
 
#10 ·
I personally use white lithium grease (I have ceramic bearings in my BB). But before that, I would take everything apart, double check that the proper spacers are in place, then grease according to the manual. Sometimes I have to give it a few tries, but this always fixes the problem for me.
 
#12 ·
Not necessarily more grease, but removing the crank/spindle, cleaning, lubing as needed, and then re-inserting it. Also, a torque wrench isn't a bad idea, knowing how close to the max you are, and all.

I've taken to using the enduro fork seals bearing kits in my GXPs, and it has never failed me. The steel ABEC 3 kit is only $20, and it's easily worth it.
 
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