I’m pretty certain I’ve read the answer already but want to double check. Sorry if
I’ve just bought some Deore XT’s to replace Elixr’s.
I was running 185mm front with 160mm rear and have bought a new 203mm front and want to run the original 185mm disc on the rear.
My bike has post mount rear rather than IS so i was going to switch the disc and adapter over straight over (after a good clean).

Do i need washers to space out the new caliper to the correct position or will it just drop straight on?

I may be wrong, but the washers you use for Elixirs take into account the thickness of the calliper. This is why they are still needed when using a 160mm rotor on the front with a post mount fork. Thus, the 185 adaptor should work with all callipers to fit a 185 rotor. However, I think the sting is that the calliper and adaptor may not sit flush with each other as avid compensate for this with the tri align system. As I said I may be wrong and there is no harm trying..

thanks donal,

that’s pretty much what i was thinking, but wanted someone to say it as well. Gonna give it a crack tonight and see how it goes