Truvativ Descendant play - wave washer?
I recently installed a set of 175mm Descendants w/ 73mm shell. I'm having trouble with play in the crankset. The problem is on the driveside. The GXP bb has a plastic 'sleeve washer' on the driveside which sits between the bearing and the spindle. When installed and tightened down there is a gap between this sleeve and the end of the spindle. Problem is the sleeve washer has been working it's way out to the end of the spindle, leaving the gap between the sleeve and the bearing - allowing play in the crankset and dirt into the greased up bb cup.
I've read I need a wave washer between the spindle and bb cup sleeve washer - but I've also read I don't need one. If I don't need one, maybe the sleeve washer has been deformed and isn't tight enough to sit still. I've got another bb to put in if needed.
Anyone know if I actually need that wave washer?
Last edited by boostin; 02-09-2013 at 04:47 PM.
How tight is the crank bolt?
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 procedures until play is eliminated.
Thanks for the reply. Crank bolt is tight. When I pull everything and grease the cups, and cranks it goes in and is tight. Its when I ride and that sleeve works its way out that the play starts.
I think either I need this mysterious wave washer or the sleeve washer in the BB cup is deformed and needs to be replaced.
press fit or threaded BB? , the press fit units need the wavy washer, threaded the seal is supposed to be set to a groove in the bearing cup and can't move....
Sram's BB/cranks are designed to have a space between the crank arm and the bearing on the drive side with the GXP system,...
this is a basic description of how it differs and why it's better..
Trail Tire TV: Sram's GXP Bottom Bracket, how it differs from others
It's a threaded BB. Here is a quote at the end of that article :
"Just so you know, If you ever install the SRAM GXP Bottom Bracket, the Drive Side seal SHOULD NOT!! come in contact with the crank arm or spider, a small gap there is a good thing..."
And thats what is happening with these cranks. The drive side seal is working itself off the bearing and out to the end of spider, creating play and allowing dirt and grim into the bearing area.
I think the drive side seal is deformed now. I've got another BB I will throw in tonight and see if the problem is solved. Its strange since this BB I am having issues with is only 4 weeks old. If the new SRAM GXP BB doesn't solve the problem I'll have to hawk some bike parts and pick up a CK BB.
Last edited by boostin; 02-11-2013 at 01:50 PM.
umm the drie side seal should be trapped inside the bearing cup if it's a GXP BB... it should never have come out.. should never have needed to be put it...
Originally Posted by boostin
did you get it new or used? It's a GXP and not the OCT version? The cranks are GXP also..? if there is play in the cranks you either have the wrong BB for the cranks or don't have the non drive side crank tight. the drive side bearing never gets any side-to-side pressure.
maybe some pics of the cranks and BB?
Oh wait.. is that a seal/spacer where it doesn't just push up to the bearing but actually has a little piece that fills in between the inner race of the bearing and the crank.. like the crank spindle is too small a diameter?? those you do need the wavy.. (those are the Oct version from what I understand.. haven't played with one)
Yea its not making sense to me. Its a GXP bb, new except I ran an x7 spiderless crank on the BB for 2 weeks before I pulled them and put the Descendants in. Reason for swapping cranks was getting my chainline right.
I've had Stylo's before and know what is tight and not-tight when setting the non-drive side bolt. When the cranks are put in fresh and the drive side seal is in place everything is tight. Its after I ride the drive side seal works out of the bb cup and to the end of the spindle.
I think the drive side seal is de-formed. It moves freely in and out of the bb cup and my other gxp bb drive side seals sit tight and doesn't budge, And yes the drive side seal is flat against the bearing between the bearing and spindle. It also has a sleeve which sits inside the bearing, filling a gap between the inner race and spindle.
I'll install the NIB GXP bb tonight and see if that fixes it. I'll also take a few pics for posterity.
OK,.. if it has the sleeve that slides actually inside the bearing's inner race and fills the difference between the bearing and the spindle then you do need the wavy washer from what I understand... I haven't played with one but from what I understand the only ones that are like that are the OCT version cranksets...
hehe... yea I don't know, I am 99% sure these aren't OCT cranks. I put the new bb cup in last night and it seems to be OK after a short spin. I'm going to take it out and beat on it tomorrow night. I'll get the pics up soon.
I don't know what happened to thrash that first bb cup in such a short time but I have a few ideas - one being that both bb cups were 3/4 of a turn loose the first time I noticed the play in the crank arms. (I didn't do the install the 1st time) Maybe the extra mm or two of bb distance forced that bb sleeve too far out onto the spindle, de-forming it.
Here is the offender- Notice how the seal isn't in the BB cup. That guy can be set in and out of the bearing with no resistance - which isn't supposed to happen apparently. During rides it would work itself out of the bb cup and to the end of the spindle. I've got a new DS bb cup in and am going to take it out tomorrow and see if the saga continues.
Last edited by boostin; 02-13-2013 at 11:51 AM.