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  • INFO Needed: 30T Race Face NW Chainline on 2×10 Shimano XT
  • binno
    Free Member

    Is anyone running a 30T Race Face Narrow wide ring on a 2×10 Shimano crank?

    I’m interested in the chain line adjustment options and any information about the 2mm offset machined into the 30T ring (is this true?).

    I understand that the 2×10 crank has a 48.8mm chain line. Can anyone confirm the chain line they get with this combination? Also, is it possible to use chain ring shims with this combo to get the correct 47.5mm chain line?

    Any info greatly appreciated 😉

    binno
    Free Member

    To expand on this:

    If i have my 48.8mm 2×10 Xt crank and add a single Race Face NW ring, i’m expecting the chain line to now be 48.8mm (centre line between the 2×10 rings + 4.5mm (half of the distance between each ring
    = a Chain line of 53.3mm.
    Minus the 2mm Race Face NW offset = 51.3mm
    Now add chain ring bolt spacers to get 47.5mm = 3.8mm spacers required.

    3.8mm spacers is a lot, i suspect to much fort he crank arms to offer a from platform for the ring to seat against.

    Removing bottom bracket spacers on shimano cups is not advised, due to the shorter cup threads on the non drive side of the Shimano Bottom Brackets. Do other manufacturers like hope etc.. have this issue too?

    As it stands, given my calculations are correct, i suspect being able to emote 1 of the 2.5mm spacers to the non drive shade and using 1.2 mm chain ring spacers, would get a near perfect chain line.

    I’m looking for anyone who can conform my calculations against real world measurements. Or any other / better ideas for getting the chain line as close to, if not perfectly placed.

    brant
    Free Member

    Chainline is 49mm on SRAM spec cranks

    neilwheel
    Free Member

    I think you need to double check your measurements OP.

    binno
    Free Member

    Chris King Bottom Brackets have the same length threads on both the drive and non drive side cups. Therefore i think i can adjust the chain line via bottom bracket spacers. Plus by using Hope 1m spacers i can fine tune the chain rings with a combination of bottom bracket spacing and chain ring spacers as required to get a perfect / near perfect chain line.

    I hope?

    BoardinBob
    Full Member

    I’m running a 30T race face NW on a Deore double chainset. Zero problems.

    whatnobeer
    Free Member

    I’m running a 30T race face NW on a Deore double chainset. Zero problems.

    Me too.

    svalgis
    Free Member

    Plenty of people seem to be running single ring setup with 2×10 cranks without offset chainrings or spacers (I used to), so you’ll be fine.

    edit: What I mean is that with the offset chainring alone you will get a better chainline than with a standard ring, which would still probably be okay without spacers.

    chico66
    Free Member

    I’m running an XT double with with a 30t Hope N/W

    Seat tube is 35.7mm diameter and from the seat tube to the centre of the ring is 33mm giving a chain line of 50.9ish? I’m also running a OneUp 42t extender. Shifting is fine and I’m having no issues

    binno
    Free Member

    Cool, thanks all, I’ll make the plunge for a 30T ring and see how it goes. Looking at the measurements provided above, i think i’m on the right page with my spacer offset. So far only found chris king BB cups that are the same thread length either drive side, maybe race face are the same?

    Either way i know i can correct if it’s not close enough to feel bob on as is.

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