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  • SRAM GX Eagle shifting – I don’t think it’s the usual suspects?
  • Premier Icon Aus
    Free Member

    OK, so a friend of a friend asked if I’d sort his gearing out, confidently said yes and he pitched up with SRAM GX 12 speed set-up. I’ve set-up a couple in the past and think they’re slightly fiddlier but OK. His drive chain is part worn, chain at 75%. Cassette has slight wobble/sideways movement (not front-back) but once the wheel is clamped up, it’s not noticeable. Cassette teeth are reasonably worn (not sure if knackered).

    Have replaced gear cable, super smooth, routed correctly. Checked mech hanger and it’s aligned. Have systematically adjusted upper/lower limit screws. Have removed cassette, no play in XD driver, cleaned, lubed and torqued up to 40nM. No spacer there, but don’t think there should be?

    So I can easily get it shifting perfectly in the top 10 gears or lower 10 gears, but always, the final 2 are out if the first 2 are OK. Adjusting cable tension and/or B-screw makes a difference, but then knocks the opposite end out.

    The mech cage looks (possibly) v v slightly out of true. But I’m looking for it! So not convinced.

    Interesting, gear 5 and/or 6 have a click as though one of the teeth is bent and the chain doesn’t sit on the tooth … but no bent/damaged/rough teeth visible.

    What am I missing, or is it new chain/cassette/ring time?

    Premier Icon thepurist
    Full Member

    Double check the cable routing through the mech – if you’re used to shimano its easy to mess up with gx and it can cause the issues you’re gettin
    Ask me how I know this…

    Premier Icon timmys
    Full Member

    I don’t think it’s such an issue with MTB groupsets but I could never get my SRAM Force 1 working properly across the entire cassette till I read on here that SRAM gear cable is 1.1 mm diameter versus others being 1.2 mm. Proper 1.1 cable sorted it.

    Premier Icon andybrad
    Full Member

    the gear click is well known with the gx cassettes that all do it

    Premier Icon honourablegeorge
    Full Member

    Because the eagle cassette is so big, a slight bend in the hanger can cause ropey shifting. I found that a hanger that shifted perfectly on 11sp needed alignment on 12sp

    Premier Icon iainc
    Full Member

    I just had a GX AXS rear mech fitted to a hardly worn drivetrain and it was back in lbs today as it was jumping on 4th smallest sprocket. Turned out that the main attachment bolt had backed off a touch and it had a tiny wobble, now it has threadlock. However the mechanic, who I know and trust, said that he checked hanger and all micro indexing, and b screw with suspension fully compressed but was finding that the chain would try and climb up a bit on the biggest 2 sprockets, when in the stand.

    He called the tech guys at SRAM who said this can happen in stand but doesn’t when riding, something to do with the tooth design on those 2 sprockets. A car park spin outside the shop when I collected it and shifting seemed fine..

    Premier Icon Paradiso
    Free Member

    I had ongoing difficulties with a GX 12 rear mech. No visual signs, but 2 of the pivots were slightly bent when I dismantled it after replacing it with an XX1 Can’t remember clattering it. Must bend pretty easily. Obviously I’d check mech hanger for straightness first.

    Premier Icon flatpack
    Full Member

    I had a similar problem and eventually tracked it down to play at the main pivot where the mech is bolted to the hanger.

    There’s a b-bolt spare set (assuming you can find one!) and fitting that fixed it for me. The X01 version fits the GX mech and seems much better made.

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