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  1. #1
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    New question here. HELP: install XTR brake on PM fork; 180mm rotor; 160-180 adapter

    I am producing a major mess with my brakes, and I need some help! I have installed a brand-new XTR brake on my Fox Float fork (PM mount). Because the rotor is 180mm, it needs an adapter. The previous brake (Avid Elixir) had this adapter (with a ridiculous number of spacers, and extremely long screws:
    HELP: install XTR brake on PM fork; 180mm rotor; 160-180 adapter-75477-2.jpg
    However, if I simply exchange the Elixir with the XTR, the brake pads will only grab half of the disk, and half of the brake pads will not have any contact with rotor. If I take out all the spacers, the screws are so long that the adapter will have play and will not fit tightly. Obviously I am doing something wrong - or maybe I do not have the right replacement parts. Also, I simply assumed that the arrow on the adapters points in the wheel rotation direction: is that correct? Many thanks for any help you provide!!!

  2. #2
    rebmem rbtm
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    Get shorter screws and don't use the Avid CPS/Tri Align Washers (spacers).
    Shimano screws are shorter then Avid screws because they don't need the spacers that Avid use.
    The arrow points in the direction that the rotor/wheel spins.

  3. #3
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    Thanks Cobba. I include a picture that may clarify the situation. The adapter is mounted in reverse, but I will fix that. As you can see, only half of the rotor's surface is polished (contact with the brake pads).

    You can also see that everything is horribly rusted, but that has to do with the fact that I have been biking in the snow for the past three months. maybe I will but a new XTR 180mm rotor as well...
    Attached Thumbnails Attached Thumbnails HELP: install XTR brake on PM fork; 180mm rotor; 160-180 adapter-2013-02-14-20.02.10.jpg  


  4. #4
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    it seems that this is the Shimano adapter. However, it looks rather identical to my current AVID adapter - or is that just me? Also, it seems that it comes with no screws. Can somebody point me to the correct screws? Many thanks in advance!

  5. #5
    rebmem rbtm
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    Shimano have actually changed from their old setup and use the cup/cone (CPS/Tri Align) washers between the caliper and the bolt head with the 180mm adapter.
    The 180mm adapter doesn't keep the caliper at 90 degrees to the bolts, if the bolts aren't at 90 degrees to the caliper they won't be able to tighten the caliper down evenly, when the cup/cone washers are placed between the caliper and the bolt head this will allow the bolts to tighten down evenly on the caliper.

    The bolts you will need would be about 6 or 7mm shorter then your current screws. If you have a hacksaw and a file or grinder you could cut your current bolts down.

    You could always double stack the CPS/Tri Align Washers so there's 4 washers on each bolt between the bolt head and the caliper.

    http://techdocs.shimano.com/media/te...9830667774.PDF
    Attached Thumbnails Attached Thumbnails HELP: install XTR brake on PM fork; 180mm rotor; 160-180 adapter-730409d1350164164-xt-brake-squeak-no-motion-036.jpg  


  6. #6
    rebmem rbtm
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    Shimano lists the following bolt sizes for use with it's SM-MA-F180P/P2 adapter.
    M6 x 37.9mm and M6 x 32.1mm

  7. #7
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    You can always Dremel your Avid bolts... Just make sure you have enough threads. If you don't know how to measure this only using a pen (Sharpie) and a piece of paper, then don't attempt this.
    Naysayers never apologize. Critics go to their grave thinking everyone else is wrong.
    ╭∩╮( . )╭∩╮

  8. #8
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    Are you trying to put the shimano brakes on avid g3cs 185 rotor?
    you have to put 180mm rotor, and 180mm adapter

  9. #9
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    Thanx guys. As always, I am impressed with the incredible amount of knowledge and helpfulness on this forum!

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