I have replaced my Avid Juicy brakes with Shimano XT M785 brakes.

It appears these need different adapters as the pads are only 2 thirds in contact with the rotor when using the spacer washers I was using before, between adapter and brake. When not using washers between the brakes and adapters, the pads have better contact.

I am guessing that running without washers between brakes and adapters removes a level of adjustment/tolerance.

Do I need new adapters?

Is it an IS to post mount adaptor?

If so (and if this hasn’t already been done) get the IS mount faced then you shouldn’t have an issue with alignment vertically without the washers.

It should be easy to line up in parallel to the disc following the many instructions online.

From the pictures I have Googled, it appears I have Post to IS type. Guessing this means the adapter is attached to the post by screwing into the side of the adapter.

There is no big issue with alignment at the moment, just an issue with depth. Although I would prefer to retain this level of adjustment.

Grateful for any advice but not sure I want to get it faced, want to deal with this at home if possible.

If the washers you are referring to are the conical/domed pair that you use with Avids then you need to take them out (both sides of the calliper).

the grey washer and domed washer pairs in the pic:

Shimano bolt directly to the adaptor, the washers form part of Avids tri-align system so their calipers are slightly differently spaced and need the washers to align correctly radially, Shimano dont.

like this:

Thanks amedias

Your answer tells me exactly what I needed to know.

I’ll add a tiny caveat….

If you’ve literally just unbolted the Avid callipers and replaced with Shimano then the above advise is valid.

However, if you’ve replaced the mounts/adaptors as well or the rotors then just check a couple of other things…

If you are using the original Avid rotors but new Shimano adaptors then double check you don’t have 165mm or 185mm rotors (early Juicy’s and BB7s did from memory) as the Shimano mounts will be expecting 160mm or 180mm and clearance may not be enough.

Likewise in reverse, if you’re using new Shimano rotors with Avid adaptors and you had 165mm or 185mm rotors then the adaptors will still be placing the callipers too far out radially and you’ll need to replace the adaptors.

If your Avids used 160mm or 180mm rotors then it’ll all be OK.