Are all shimano disc brake calipers compatible?

[Bobby]

I have some leaking road bike disc calipers, and want to replace them with non-leaking one

I think they are all compatible with each other, but wondered if I'm missing something?

Thanks in advance,

[rafletcher]

You're not missing anything. 

[Bobby]

You're not missing anything. 

  thanks

[grams]

Yep. MTB ones too.

Be careful some take banjo fitting me and some have a straight fitting.

[FifeingEejit]

There is an incompatibility in the Shimano systems in that they used to use a wider brake track and therefore pad.
There's a tech noc somewhere on the shimano website that tells you which calipers+pads fit which rotor width.

There aren't a lot of 16mm shimano systems though and the road ones are all 14mm.

[Brucey]

there are variations in piston size but most of the shimano  brakes have about the same MA. Obviously you need to use a disc with a track width that matches the caliper.

cheers

[zigzag]

there are two types of brake hose (and associated fittings) - does it matter if the lever end requires one type and the caliper another?

[FifeingEejit]

there are two types of brake hose (and associated fittings) - does it matter if the lever end requires one type and the caliper another?

No, the XT M785 and related systems used a Banjo at the caliper and the standard olive etc at the lever.
I never had leakage from the banjo but many did.

Also Shimano's "new" easy fit system appears to be a case of the pipe being pre-fitted with a barb, and the olive sitting waiting for the pip to pass onto it and the bolt to be tightened...

[Bobby]

Seems like I'll need a different adaptor - both calipers are 'flat mount?' but have different distances between the holes

[grams]

The base plate on flat mount callipers is is reversible so they can fit different size rotors.

[FifeingEejit]

The base plate on flat mount callipers is is reversible so they can fit different size rotors.

The flat mount fronts come with a reversible 140/160
The flat mount rear is 140 and you need the wedge to put it on a 160 disc, this wedge of course doesn't come with the caliper.

It's almost like the expected set up is 140/140 or 160/140 and only outliers will use a 160 on the back...

[Bobby]

The base plate on flat mount callipers is is reversible so they can fit different size rotors.

Seems like I have IS mounts on my forks, and the adapter that turns it into a flat mount puts the holes ~70mm apart instead of the 75mm distance that the reversible base plate has.

I probably need to measure these more precisely to work out what to buy next! 

[grams]

Sadly you can’t fit flat mount callipers to anything but a flat mount fork/frame - the geometry makes adapters impossible. I think you were after post mount callipers.

Hopefully you can get a refund.

[Bobby]

Boo.  I didn't think about different mounts

So far:
- I have IS mount forks
- An IS to Post mount adaptor & the old calipers were indeed post mount
- New shimano calipers are flat mount


Cant yet find an IS to Flat adaptor

[FifeingEejit]

What are the calipers you have?
SJS still have RS785 Post Mounts for sale
https://www.sjscycles.co.uk/brakes/shimano-brrs785-road-post-mount-hydraulic-disc-brake-caliper-front-or-rear/

If you're 160 discs front and back then MTB calipers will do the job too, other advantage of MTB calipers is the selection of pads is wider and cheaper if you look at the likes of Uber Bike Components and Superstar.

[grams]

Cant yet find an IS to Flat adaptor

In the past I’ve tried to design one in CAD and quickly came to the conclusion it would have to have negative height, so physically impossible