My work colleague has bought a secondhand set of Hope Mono M4 brakes from eBay. They were advertised as being to fit 180mm front and 160mm rear rotors (the main reason for purchase, his bike came with 203mm rotors front and rear). Having sourced the appropriately sized rotors, we’ve just tried fitting the brakes and, in short, they don’t.

After a lot of faffing about, we’ve established that one of the calipers (No 3 stamped into the back) aligns perfectly with the 180 rotor when fitted on the front and the 160 rotor when fitted on the back. The other caliper (No 8 stamped into the back) sits the pads too far above either rotor in either position.

Can anyone tell me what size rotor the No 8 caliper is designed for?

If it makes a difference, both calipers are IS, being mounted on a 2004 Fox F80 RLT fork and a 2009 Specialized S-Works M5 hardtail frame, Shimano SM-RT97M centrelock rotors and Shimano RM65 hubs.

It sounds like there are adaptors on the calipers already, and they’re not the right size for your rotors.

Have a look at this picture

If there is anything attached to the holes at the bottom, it’s an adaptor.

I think the 8 caliper is 200 front / 180 rear -but why not check with hope?

Dan, there is no adaptor on the caliper, we were bolting the caliper directly to the IS mount on the fork leg.

Jeremy, that’s what I’m thinking too. I’ve just tried his 203mm Shimano rotor in the No 8 caliper on the front and it’s fractionally too big, indicating a 200mm rotor size. We have emailed Hope and are waiting for a reply. Thought I’d check on here too though.

sounds like you’ve got a 180 all round setup to me

TJ’s right and I’ve fitted,still have, with 203 rotors. It does slightly touch the caliper at first but soon stops when they wear abit.
CALPIER SIZES