Nomad, 73mm BB shell, GXP, has one spacer - is that right?

Anonymous
Anonymous Posts: 79,667
edited May 2012 in MTB workshop & tech
Quick check. Just fitting an ISCG mount chain guide to my Nomad and having taken off the 2x10 X0 (GXP BB) cranks, I notice there's one spacer on the drive side.

Given it's a 73mm shell, I thought there should be no spacers?

Quick look at the manual and for 73mm there's a big cross through the spacers on the diagram, which I assume means no spacers.

But the bike has been riding fine so far with that one spacer there, all indexed fine. It's as it was supplied from LBS who had it as one of their pride and joy demo bikes so has been running like that for some time.

I'm wondering if there's some special reason for having the one spacer and is there any harm in leaving it like that?

Other things of interest - X0 front mech (despite SC saying they don't work), and it's a 10 speed set up.

Comments

  • Anonymous
    Anonymous Posts: 79,667
    Hmm, fitting the guide (Truvativ X-Guide), it seems to line up perfectly. No spacers required on the guide, chain lines are fine.

    Thinking the spacer on the BB on the drive side was maybe put there just for the purpose of fitting a guide. Hmm, not sure.
  • nicklouse
    nicklouse Posts: 50,675
    Often people fit a spacers as they don't read the manual.

    In the best it does nothing in the worst it trashes a bearing.
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  • bennett_346
    bennett_346 Posts: 5,029
    Mine is 73mm GXP and does not take a spacer, i don't think that yours was put there on purpose, i think someone read something wrong when they assembled it. Also they don't usuallyfit a guide properly.
  • Anonymous
    Anonymous Posts: 79,667
    Well, it all fits together fine with cranks done up to correct torque, and still has the little 2mm-ish gap on the drive side as normal (now I know that GXPs are supposed to have this gap). Maybe the crank spindle length just gets away with it.

    Couldn't be bothered to take the BB off. I have bad luck messing with BB cups and removing the spacer I'd have to re-index it. When the bearings go I'll do it properly.
  • cooldad
    cooldad Posts: 32,599
    Just check the arrows before getting stuck in with a monster breaker bar. You won't do that twice.
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  • mrmonkfinger
    mrmonkfinger Posts: 1,452
    Chainline is fixed by the non-drive side on a GXP. Providing you have a tiny gap (drive side), the spacer won't make any difference to anything... but its not required.

    As Nick says, if the drive side was pressing up against the bearing, the bearing would be trashed very quick. If its been like that for ages... its probably doing nothing and you're ok = might as well leave it alone.
  • Anonymous
    Anonymous Posts: 79,667
    Good point. Drive side always had the tiny gap, and still does after re-assembly (and the usual faffing about with the GXP dust cover on the drive side). So should be good then, cheers.

    I guess it's the same as having put a BB mounted guide in there anyway.