Because of tyre issues I put my spare wheels on the bike that they haven’t been used in before.
However I can’t get them to stop rubbing in the calipers despite doing all the normal things – centring ,pushing pistons right back etc. The discs are fairly new and the pads aren’t bad and they work fine in the bike I usually have them in. Is this down to uneven pad wear or am I missing something obvious? [hubs are same size , no trace of boost here]

Same hub make and model? If not, I don’t think there’s any “standard” for how far along the axle a disc actually mounts.

if they’re rubbing despite recentering etc then it’s not hub standards that are at fault.

Are the disk hitting the caliper itself or the pads? Both ends or just front or rear?

You’ll have to tweak the position of the calipers when using a different set of wheels, unless you’re very lucky. They all differ by a mm or so.

Could it be TH difference between 180 and 183 rotors and its just catching TH caliper? Try th original rotor on the spare wheel.

It could also be that one set of rotors is thinner (more worn) than the other. If the brake pads are new or there’s slightly too much hydraulic fluid in the system then the pads could be rubbing on the thicker set. I have two wheelsets for my Pact and one has slightly more lever movement on account of rotor wear.

I had the same problem. I got some of these and now I don’t.

http://www.halfords.com/cycling/bike-parts/bike-brakes/a2z-disc-brake-caliper-spacers

You have to fit them, obviously. And figure out which wheel to space. Just buying them won’t work on it’s own.

wow – nedrapier’s a metolympian !

Yep spacers were the answer! Application of two thinnish washers between mount and caliper were enough to improve the rear markedly. The front which was never as bad as the back sorted itself after a short ride.
Thanks for all the suggestions

Good work.

But you’ll have to reverse that when you swap back to your other wheels.

If you going to be swapping back and forth more than a couple of times a year (or even more than once!) space whichever rotors that are furthest inboard. The wheels will then be near enough identical and you can swap back and forth without messing with your calipers.

And if your are going to space the dics out then some full size shims rather than washer would be better, these

Definitely less of a faff. only have to position it once (or twice if you need two), rather than 6 or 12.