While trying to restore an older bike, I wanted to mount a rather old Magura Louise 2004 IS disc caliper (160mm rear) to a new Kona project 2 disc-compatible fork. I got a Superstar 160mm rotor only to learn that 160mm rear means 180mm front but besides: The caliper is mounted right against the fork, and the rotor against the hub (Shimano dynamo hub), still the caliper is too far inboard (or the disc too far outwards) and the outer brake pad rubs on the disc (both pistons fully pushed in). If it was the other way around, I could use washers/spacers, but what do I do in my case? Face either the new fork or the caliper by a few tenths of mm? Or alternatively, since I need a 180mm instead of a 160mm rotor anyway, should I go for a 203mm rotor and get one of these Hope, Shimano, or Brake Authority adapters? Does anyone know whether they give a bit of a negative offset? Or are the old and new mounting points directly inline.
I mixed and matched road (Kona forks and hub) and MTB (old Magura brake) a bit but wouldn’t have thought that’s causing issues, but happily being told differently. Don’t want to buy new PostMount disc brake as current Magura one is freshly bled and working fine.
Any help appreciated, thanks.

From what you have said I think facing the caliper would be the best option.. my experience with adaptors is they don’t give you a negative offset but again could be faced and not as expensive if messed up??

If new forks would leave well alone!

face the fork mount – may need to give it a couple of passes.

I’d face the forks myself. are you useing a centrelock disc / adaptor? sometimes that causes issues Or can you move washers /cones around on the axle to move the hub across a bit?

Thanks for the replies so far! It’s a 6-bolt disc mount… Good idea with the washers on the hub but while I normally happily strip hubs (before use to grease them), I left this one alone as it’s a dynamo hub and looked more involved to get into, so don’t want to mess with washers (was also my first complete wheel build and don’t want to re-dish the wheel).
Sven

based on GUESSES:

I’d face the caliper (if it’ll leave enough material behind) – it’s old, you’re not really destroying any secondhand value.

If you take material off the fork you’ll be spacing out any other brake you ever put on it from now on (unless the fork is to some weird standard anyway)

Cheers, thanks again for the replies, I am still undecided but will probably work on it tonight again.

You can move the disk outwards with shims from Syntace

EDIT: Arse, ignore me