Front rotor adaptor bracket



sopel

New Member
Dec 8, 2010
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Hi there! :)

I am new to the forums and still a bit lost here :)

I have a little dillema with the adaptor bracket for my front disc brakes. The thing is that I now have a 185mm rotor and I need to get a 203mm one- in order to mount the brake calliper onto that "beastly" rotor I need an 203mm adaptor bracket. And my question is, are those brackets the same? I know the one is a blueprint drawing and might be hard to compare but please help me out. Below I post the two pics I found out. From my judgements they appear to be the same, I just need to be sure! :)

I NEED THIS ITEM


THIS IS THE ACTUAL THING I INTEND TO BUY



Do you think they are exactly the same thing or should I keep searching?

Thanks a lot!
sopel :)
 

tafi

Active Member
Jul 31, 2003
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Post-mount disc brakes are all made to the same mounting standard. That's why you can whip a shimano brake off a Fox post-mount fork and put an avid on in its place without any modification. Provided the adapter is designed for a 203mm rotor (this should be stamped somewhere on it the adapter) it should be fine.
 

dabac

Well-Known Member
Sep 16, 2003
2,298
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Aren't Avids a bit special, or is that difference in the caliper? They've got those Tri-Align washers that go between the caliper and the bracket.
 

tafi

Active Member
Jul 31, 2003
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The offset required for the spherical washers is in the Avid caliper, so the important dimensions of the mountings should be equivalent.

As I mentioned above, we can use the example of Fox, who only make one type of post mount to suit any company's brakes. To that you would fit either a Shimano caliper or an Avid caliper with the washers. A long as you use the washers with the Avid caliper then the two should be equivalent (for the same diameter rotor).

Now: Caveat Emptor: Different rotors have slightly different thicknesses and diameters even if they are made to the same "standard". This means that a certain amount of adjustment (with thin washers/shims etc) may be necessary to prevent the rotor from topping out on the caliper body. Everyone's mileage varies in this respect but it is only a matter of fine adjustment.

Also, though it won't be a problem here since you are going for a larger disc, if you were to go for a smaller disc there could be interference between the mounting and the caliper body. In that case it is better to try to match the caliper and mount.