XT M785 brake calipers - front & rear interchangeable?

mikewoods

Anyone know if there's a difference between the front and rear calipers on the M785 XT brakes. I need a front brake but the only right hand level CRC has is a rear setup. Can I just buy that and shorten the hose to suit?

nicklouse

and you will need the correct adaptor for the dosc size you use.

mikewoods

ive just used the Avid adpater that was there before on the rear - can I use the same on the front?

supersonic

Yes and no - an IS adaptor for 160mm rear will be 180mm for the front.

mikewoods

Its a front PM adapter - 200mm

nicklouse

a IS to PM adaptor is a IS to PM adaptor. some may need the aplication of a file some dont.

but as coved in the FAQs and as Soinic said Front and rear are NOT the same.

mikewoods

I might not have been clear - the brakes im replacing are pm to pm mount already with a 203mm rotor - Previously had Elixir 5's on. I was planning on leaving the mount there and just attaching the XT caliper to it - but was wandering if a rear caliper could be used.

nicklouse

as said the calipers are the same.

mikewoods

cool thanks

cobba

When you swap the brakes over don't use the CPS / Tri Align washers that were on used with the Avid brake, if you use them with the Shimano brake they'll pack it out too much and the pads will overhang the outer edge of the rotor. You might need shorter bolts when doing the brake swap.

mikewoods

ah ok - I have already swapped the rear over and used the avid mounts with the washers I havent yet tried them or shortened the cable so cant say Ive notice any overhang - will check tonight but for the sake of like £6 each might as well get the shimano mounts.

cooldad

The mounts are fine, just don't use the washers.

mikewoods

Without the washers the mount doesn't provide the right spacing. I cannot find a rear post mount to post mount shimano adapter anywhere!!

mikewoods

Ok am I being stupid - is there a difference between front and rear mounts - can find plenty of front post to post mounts

camerauk

I have fitted a set of the XT brakes to my bike which had Elixir 5's on, I used the mounts that were on the bike just attached the new callipers with the bolts that were supplied with the new XT brakes which were shorter than the ones that were on the old Elixir 5's and did not use any washers from the old brakes

mikewoods

Ha I've not even looked at the bolts that came with the brakes just mounted the calipers with the old bolts from the elixirs! I see you've got a camber expert too - how did you find the brake upgrade?

cobba

mikewoods wrote:

Ok am I being stupid - is there a difference between front and rear mounts - can find plenty of front post to post mounts

There might be.
IS mounts are generally 160mm on the front and 140mm on the rear.
Post mounts on the front are generally 160mm but this can vary, they can also be 180mm or 200mm.
Post mounts on the rear can also vary, I've seen 140mm and 160mm

160mm Post Mount + 203mm adapter = 203mm rotor
140mm Post Mount + 203mm adapter = 183mm rotor

Post some photos.

camerauk

mikewoods wrote:

Ha I've not even looked at the bolts that came with the brakes just mounted the calipers with the old bolts from the elixirs! I see you've got a camber expert too - how did you find the brake upgrade?

They are fantastic much better than the Elixir 5's although they were ok just had a few problems with the squealing and they did not feel great brakes they were just ok, the XT's stop with just one finger braking great modulation and no more noisy braking

mikewoods

How were you able to use the avid mounts without the washers? Looking at mine tonight, if I take out the washers there won't be enough clearance for the rotor - just swapping the calipers looks fine!?

cobba

Post a side on photo of the setup.

Is the adapter on the right way around ?
Are you using the right adapter ?

camerauk

mikewoods wrote:

How were you able to use the avid mounts without the washers? Looking at mine tonight, if I take out the washers there won't be enough clearance for the rotor - just swapping the calipers looks fine!?

I just unbolted the old calliper and bolted the new one back on using the new bolts supplied
Can take a couple of pics if you need them later
But I had no trouble just to note I have 180 rear and 203 front

mikewoods

Yeah that's the same set up as mine - so you have used the 'cup and cone' washers that are either side of the calliper?

cobba

so you have used the 'cup and cone' washers that are either side of the calliper?

You must of missed..........

and did not use any washers from the old brakes

Post some photos so everyone can see what's going on.

camerauk

Here is my rear brake

mikewoods

Can't post a picture because ofthe size limits but I see the difference - mines post mount at the rear! What year is your camber?

Got the breaks on and they are superb!

camerauk

Mines a 2011 camber expert

cobba

mikewoods wrote:

Can't post a picture because ofthe size limits

Resize them or put them on a photo hosting website like http://www.flickr.com or http://www.photobucket.com and post a link to them.

The Rookie

The mounting points on the caliper are different so you need them for Avid and not for Shimano, I did the same when I switched from Avid to Shimano, rmove bolts with washers, fit shimano without and with shorter bolts.....

mikewoods

Heres my rear caliper mounted the washers but I see now, when taking this pic, that the rotor does not sit high within the caliper - hence why the washers should not be used. Interestingly when I get back to the office CRC have delivered the shimano 180 mount and what do the bolts have - washers! will fit them tonight

mikewoods

Shimano mounts and bolts now being used - definitely easier alignment with avid stuff! lol

cobba

mikewoods wrote:

Interestingly when I get back to the office CRC have delivered the shimano 180 mount and what do the bolts have - washers!

Those washers go between the bolt head and the caliper, they don't go between the adapter and the caliper.