I thought that the IS standard was 160, so you should be able to get a 180 adaptor

this one

Sadly no - I have a 180 caliper.

And using an adaptor increases the distance between the axle and the mounting bolts -my only options, if I wish to still use an M4 are:

- a new PM caliper and new rotor (either both 160 or both 183)

- an old 160mm IS caliper, with an adaptor and my existing rotor

- my existing IS caliper plus adaptor and a 200mm rotor.

Of these the middle one is preferable, both for cost and practical reasons.

mark

Must be the old Mono M4 caliper then at a guess think they came at a set size, whats your rear caliper ?

If its a smaller size 140/160 [as was usual with Hope] you may be able to swap them around 180 on the back and the 140/160 with an adapterand new rotor on the front.

@ XCman:

The rear is a 160mm. I had wondered if you could swap them, but since no-one I've talked to had mentioned that I'djust thought the front and rear were incompatible. Certainly that would be the simplest and cheapest option (just a new 180 rotor for the back). Are you sure they are inter-changeable like this?