I’ve got a bit of disc rub and the rotor isn’t centralised. I’m guessing you have to use longer fixing bolts and some shims/thin washers.

Is this right, if it’s not how do you do it?

It’s not easy as set up post mounts. 😐

Thanks in advance

Correct. Long enough bolts + shims. If lbs doesnt have them in stock Halfords often do.

if the IS mount isn’t faced its worth doing if its difficult to align as m4’s have a long pad contact area so exaggerates any misalignment.

yes, use shims. Most ‘washers’ will probably be too thick and move it too far the other way.

No need to use longer bolts though, we’re only talking fractions of a mm.