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  • Shimano - SM-MA90 Disc Brake Adapter - One Color
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  • Shimano - SM-MA90 Disc Brake Adapter - One Color

Shimano SM-MA90 Disc Brake Adapter

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    • One Color, Post, 180mm
      sale $11.95
    • One Color, Rear ISO, 160mm
      sale $11.95
    • One Color, Rear ISO, 180mm
      sale $11.95
    • One Color,Rear ISO, 140mm
      sale $11.95

    21 Reviews


    SM-MA90 Disc Brake Adapter

    With the SM-MA90 Disc Brake Adapter, Shimano has taken an artful leap at the lowly disc brake adapter. Not only is it lighter than their older adapters, but it's more refined -- this refinement being the reason for its lightness. Where Shimano's older adapters were blocky, this one has curved edges. Where they were solid, this one has a window machined out of the center of the adapter body.

    The Shimano SM-MA90 Disc Brake Adapter is available in five versions to fit 160 and 180mm rotors for front ISO or Post mounts and rear ISO mounts.

    • Handy brake adapters for switching up brake style
    • Capable of adapting post mount or ISO mounts
    • Curved edges are streamlined for slick setup
    • Cutout window sheds weight on setup
    • Available for 140, 160, and 180-millimeter rotors
    • Item #SHI0547

    Tech Specs

    Shimano front ISO/Post and rear ISO
    Recommended Use
    getting calipers to fit correctly
    Manufacturer Warranty
    1 year

    Tech Specs

    • Reviews
    • Q & A

    What do you think about this product?

    Have questions about this product?

    Does the job like a boss

      This adapter does exactly what it's supposed to. If you have post mounts and want to size up your rotors, this is the one you need. Not sure anyone actually uses the included safety wire, but its cool that Shimano includes it.

      Best brake adapters

      • Familiarity: I've put it through the wringer

      Shimano makes the best brake adapters. I don't always run Shimano brakes but I always use their adapters. They are easier to set up than others on the market and seem to be the best design available.

      So you went XTR

        We see that, and we respect that. Now, make sure that everything plays nicely together by making sure you use the correct hardware. These not only drop weight, but use a different bolt to match with the XTR calipers.

        Not just for 180

        • Familiarity: I've put it through the wringer

        Got the 180 post mount adapter. Essentially its a 10mm spacer used to increase rotor size by 20mm. Worked great with TRP HYRD to mount 160mm rotors on a Ritchey cross fork. Also used it to swap up from 160 to 180 front rotor on my mtb bike. Does what it needs to do.

        Highly Adaptable

        • Familiarity: I've put it through the wringer

        These can be a little confusing, call a competitive sales rep if you need guidance. The Shimano adaptors are primo, and work nicely with Shimano brakes, or whatever else you happen to be using.

        Basic excecution

        • Familiarity: I've put it through the wringer

        It is amazing that a seemingly basic component can be done in so many different ways at different degrees of successful execution. Shimano does theirs very well. keeps the caliper stable and in the correct position with very little, if any flex. You need this adapter for most builds today.

        gotta have it

        • Familiarity: I've used it several times

        My fat bike came with hydraulic 160mm rotors in front and back. For winter, I wanted mechanical brakes and figured I'd upsize the front. Need an adapter to accommodate the 180mm rotor. I used this even though installing TRP Spykes with an centerline rotor--it's all working well together.

        Upgrade to 180

          I recently installed new rotors on my Santa Cruz Tallboy LTC. After riding a friends bike which had 180mm rotors front and rear, I decided I'd do the same. It's made a noticeable difference for sure. I got the Post for the front and the ISO option for the rear. Just a heads up sometimes ISO is referred to as IS.

          Unanswered Question

          I have a 140 post mount rear and I want to use a 160 disc rotor, which adapter do I choose?