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sram x01 gpx fitting

sh3psh3p Posts: 98
edited September 2017 in MTB workshop & tech
hi all,
just looking for some advise, i recently bought a sram x01 gpx crankset, when i came to fit it i had way more room/space on the drive side.
I do understand this is determined by the non drive side bearing/cup and you would use the 2.5mm spacers to set the chain line, (73mm bb) if i set the chainline with no spacers drive side, the non drive side threads don't reach the frame threads, I've had to use 3 spacers (approx 7.5mm), just so i can use the same on the nond drive side, my concerns are twofold.
1. is approx half the amount of threads available enough?
2. the chainline is a long way out akthough i suspect a 6mm offset chainring will solve that .

any advise greatly appreciated :)

Posts

  • The RookieThe Rookie Posts: 27,748
    Are you saying you have three spacers each side?

    GXP should (must) have a small gap between the driveside crank and the bearing, the bearings operate with no preload, have no gap and it's so long bearings, what size gap do you have?
  • sh3psh3p Posts: 98
    i have 3 spacers non drive side and 2 drive side (3 was too many) and have 1-2mm clearence, the problem stems form the length of the axle which is 122mm the original axle was 114mm, i think the crankset is for a 83mm BB, whereas mine is 73mm.
    i do understand how the gpx system works with the drive side floating and the chainline set by the none drive side essentially being trapped by the axle lip and bearing.
    i was hoping there would be some sort of insert to extend the threads in the BB or a bearing cup that had deeper threads to allow more spacers on the none drive side to pull the chainline in some more.
    It does work as it is using an 1xx spider for 12speed that i had, although i may get a 6mm offset oval.
    Any other suggestions or advise is greatly appreciated.
    thx Shep
  • 02GF7402GF74 Posts: 1,294
    sh3p wrote:
    the problem stems form the length of the axle which is 122mm the original axle was 114mm, i think the crankset is for a 83mm BB, whereas mine is 73mm.
    i do understand how the gpx system works

    Firstly it is gxp. :)
    I don't recall there being any spacers on mine. I fitted gxp to a pf30 and made my own adapters. To get correct preload I got a gxp wavey washer, this may help you as it may take up the gap.
  • sh3psh3p Posts: 98
    eek indeed gxp :) nothing I've seen suggests a wavy washer other than with the Shimano BB bearing assembles i do have 1 from a shimano BB and wkll take a look ty :)
  • The RookieThe Rookie Posts: 27,748
    So you are trying to install the wrong crankset for the frame, go get the right one, that will never work properly and it's a waste of time trying to force the issue.
  • 02GF7402GF74 Posts: 1,294
    ^^^^^^it can be maser to work with a bit of ingenuity as I managed it with pf30.

    If you measure bb width and spindle length of crank torqued up off the bike, subtracting the 2 will give spacer length.
    There is aluminium tube of 24mm I. D. That you buy and cut to length using a pipe cutter, cut s bit shortened use wavey washer to avoid overdoing the preload. The chainring may be too far out but maybe corrected with off set or spider.

    It is a lot of faff bearing in mind gxp carbon chain set are about £70 on eBay.

    Ofcourse there is always the option of fitting the correct part as Mr R states but where is the fun in that????!!???!?!?!!! 3???
  • sh3psh3p Posts: 98
    cheers for all the input guys,as i do have clearence drive side, is all torqued up and appeared to shift all ok with the offset spider I went for a shortish ride (14miles)roads,woods and bridleways and all worked fine,the chainline in 1st could be better but no chain drops or miss shifts.
    Yes had i been aware of the axle length, I wouldn't have bought it but i didn't and I did, unfortunately I don't have the cash to just get another the correct size atm.
    once again thx for the replys/help
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