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  • New XTR cranks – question
  • Premier Icon woody71
    Free Member

    Hi all

    My race fave next SL cranks have started to come apart at the spindle so need something to replace them. I don’t have a receipt so no warranty and I don’t want to throw good money after bad.

    So thinking about the new XTR cranks but have a couple of questions

    – will the narrow Q factor 9100s work with a 148mm boost rear end?

    – can you buy after market Chain rings that are compatible with normal 11 speed chains (I don’t want to have to replace chain and cassette)?



    Premier Icon sillyoldman
    Full Member

    The chainline is the same on both the 9100 and 9120 – it’s the Q-factor that differs.

    It depends on chainstay profile rather than dropout dimensions. If you have 8mm or more clearance between chainstay and pedal boss on current cranks then you’re probably OK.

    Plenty people making aftermarket rings to suit, but all I’ve seen have been 12 spd hyperglide+ versions. Likely to be something though?

    Premier Icon JonEdwards
    Free Member

    Not seen any 11s rings, but you can use a 12s chain on a 11s cassette fine – it’s what I’m doing. 9120 cranks, Absolute Black oval ring, Shimano 12s chain, Sram X01 cassette. Works lovely.

    Premier Icon woody71
    Free Member

    Cheers both

    Very helpful

    Looks like I’ll need at least a new chain then

    Premier Icon dreednya
    Full Member

    I know slightly different, but Had the 9020 cranks (non-boost) and they didn’t work when my rear triangle was warrantied for a boost version as that was all that was available. 34T front ring made contact with the chain stay. Free rear triangle, but had to buy new cranks and rear hub, but I guess the bike is now future proofed for now at least

    Premier Icon GolfChick
    Free Member

    I saw some XT cranks for sale so looked into it and found a wolftooth chainring that fit them and came in 11 spied profile. Was £80 though and no chance I’m paying that for something as wearable!!

    Premier Icon benpinnick
    Full Member

    12spd rings will run 11 chains just fine I’d expect. Backwards compatibility normally works

    Premier Icon damascus
    Free Member

    I fitted the narrow q factor xtr cranks (are they m9100?) on my scandal but they arms hit the chain stay. The wider q factor ones worked (are they m9120)

    They aren’t the boost versions but work OK but I’m running 10 speed on my winter bike.

    I think I’m currently running a black spire nw oval chain ring from crc that was £35.

    Premier Icon Onzadog
    Free Member

    I thought the 12 speed stuff was single chainline, 52mm, neither boost nor non-boost.

    Premier Icon woody71
    Free Member


    I think the wider q factor ones (9120) are what they refer to as their boost ones for 148mm although they also say that the narrow Q factor ones work for 142 and 148.

    I guess the question is about rear stay shape and whether it’ll catch or not.

    Is the black spire ring for standard narrow/wide or the new Shimano profile?

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