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  1. #1
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    Help: XT caliper-rotor alignment

    Anybody know what's going on here? Shimano XT brakes, rear Shimano XTR 160mm IS adapter, Shimano 160mm XT rotor, but significant misalignment of caliper and rotor. The caliper only contacts the outer half of the rotor brake track... Am I missing something? Any thoughts are welcome, thanks! Help: XT caliper-rotor alignment-dsc_0027.jpg

  2. #2
    rebmem rbtm
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    What's the frame?

    Pull the pads out and see if they're starting to wear like the pads in the following photo.

    Help: XT caliper-rotor alignment-831692d1379103670-shimano-xt-brake-pad-wear-issue-img_7701_small.jpg

    If they are then the IS mounts on the frame mightn't be set at the 140mm size that normal rear IS mounts are.

    The adapter you have is for 140mm IS mounting specs.

    Check the IS mount measurements:

    140mm: http://www.hayesdiscbrake.com/wp-con...2101_5inch.pdf
    160mm: http://www.hayesdiscbrake.com/wp-con...7886_6inch.pdf
    180mm: http://www.hayesdiscbrake.com/wp-con...4/98-18646.pdf
    203mm: http://www.hayesdiscbrake.com/wp-con...4/98-17887.pdf


    If the pads are getting full contact with the rotor then there mightn't be a problem, it might just be the rotors braking track is larger then the braking material on the pads.

  3. #3
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    Yes, that's exactly what my pad wear looks like! So what should I do if I have the 160mm spacing (I'll confirm with frame manufacturer tomorrow)? Does Shimano make such an adapter? I don't recall seeing that option... Thanks for your help!

  4. #4
    rebmem rbtm
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    If the frame has 160mm IS mounts then you'll need to use a front 160mm adapter, the 'size' of the front adapters is based on 160mm IS mounts.

    SM-MA-F160P/S: http://www.bikeman.com/BR8911.html

    160mm front adapters are the same as 140mm rear adapters, you could also use the SM-MA-R140P/S adapter or a SM-MA90-R140P/S adapter if you have 160mm mounts.

    160mm front/140mm rear adapters don't increase the rotor size on IS mounts.
    eg: 140mm IS mount = 140mm rotor & 160mm IS mount = 160mm rotor

  5. #5
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    Cobba, you are brilliant! Thanks SO much. New bike and I can't ride it, so I'm excited to get back on the trails before the snow sets in. Thanks again!
    Last edited by murphyo7; 10-29-2013 at 09:30 AM.

  6. #6
    rebmem rbtm
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    Does the frame has 160mm IS mounts ?
    160mm front / 140mm rear adapter fixed the problem ?

  7. #7
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    I haven't confirmed it yet, but will pick up a new adapter today. I'll post back here with final results. Thanks again!

  8. #8
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    Well, turns out the front 160 does NOT work. I put a call into the frame manufacturer, but didn't hear back so decided to give the front mount a try. Too short. I'll do some more research and get back to you. Thanks!

  9. #9
    rebmem rbtm
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    Quote Originally Posted by murphyo7 View Post
    Too short.
    By how much?

    The front 160mm adapter will move the brake caliper 10mm closer to the axle then what the rear 160mm adapter does.

    If with the front 160mm adapter you need to pack the caliper out about 5mm more, you could use some shims or a CPS washer stack like what Avid uses with some of it's brakes.

    Help: XT caliper-rotor alignment-elixir9_caliper_storm-grey-ano.jpg

  10. #10
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    Thanks, I'll give that a shot tonight when I get home. More later...

  11. #11
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    Well, I'm a moron. Turns out there was some packing foam crammed into the left dropout. Hence the brake issue. So sorry for the hassle, but thanks so much for your time. Take care.

  12. #12
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    Help: XT caliper-rotor alignment

    Lol. Good work everyone.


    "You're like a Ferrari engine driving a dump truck"

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