Currently I have a Tektro Auriga brake system. I don't like the Auriga brakes at all, so I decided to replace them with Deore XT BR-M800.

At front I have 180mm disk and between the caliper and fork is an adapter. I'm curious about the rear caliper. Will the new caliper fit without an adapter with a 160mm disk? Here are pictures of my current brake system.(couldn't upload directly due to image sizes)

  • 1
    This very difficult to answer without more info about your frame and existing setup
    – Paul H
    Commented Jun 7, 2019 at 16:14
  • @PaulH I'll upload pictures soon.
    – Pararera
    Commented Jun 7, 2019 at 16:35

1 Answer 1


If the rear Auriga used no adapter for a 160mm rotor, the new M800 won't need one either.

Post mount frames can be understood to have a "native" rotor size, the size of rotor that a caliper works with when mounted without an adapter. For some bikes that size is 140, which would mean you would need an adapter, but it's mostly road bikes where you see that, not a hybrid or mountain bike that would be more likely to come with the brakes you have. Likewise some rougher stuff MTB bikes start out at 180 in the back and can't run a 160.

  • Thanks for anwser! Only think that confuses me is mounting style of rear caliper.
    – Pararera
    Commented Jun 7, 2019 at 16:47
  • Does I-Spec or II-Spec apply on calipers or just on levers etc.?
    – Pararera
    Commented Jun 7, 2019 at 16:51
  • 1
    I-Spec is Shimano's lever/shifter/etc integration system, similar to SRAM Matchmaker. It doesn't affect what's happening at the brake end. Commented Jun 7, 2019 at 17:35
  • What about front caliper?
    – Pararera
    Commented Jun 9, 2019 at 17:13

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