i.e. is a 180mm Avid rotor compatible with Hope calipers etc?
Yup, AFAIK - if the diameter's the same they should work on anything
usually, Teh thing to watch out for is the width of the rotor track. Some pads are deeper than others so on the wrong rotor run on the spokes a bit.
Some pads are deeper than others so on the wrong rotor run on the spokes a bit.
Is that a problem? I've just swapped a 160mm rotor for a 185mm and looking at the tracks the pads have made, they are definitely running over the inside of the main rotor section onto the spokey bits. Especially annoying if it is, as it's all Avid kit, no mix'n'match, and the adaptor stated that it's specifically for 185mm.
I guess it might weaken when your discs wear down.
It's not something that concerns me.
aren't avid 185?
I had a 180 shimano disc running with a 183 hope caliper. Eventually you get a lip on the top of the pads and once they butt up against each other you get no braking.
Braking on the spokes of the disc is not a great problem, but it can lead to a bit of vibration - I have deore calipers with lx(?) discs and the pads do overlap onto the spokes, when I pull the front brake on I get a slight judder as the spokes go through.
Hope floaters can be a problem. Had to fettle my Juicy's a bit.
Some rotor thicknesses are fractionally different (talking 0.1 / 0.2 mm here)which can cause differences in lever bite positions. Dont think it is a good idea to run too small diameter, even just by 3-5mm overall, a rotor though as youre losing braking efficiency by not using all of the pad surface in addition to causing a lip on the pads.
Hope floaters can be a problem. Had to fettle my Juicy's a bit.
+1 with Hope floaty rotors and newer Magura Martas - gave up in the end and switched to Venti rotors
when I swap my wheels (and disks) over the bite position changes slightly but a couple of squeezes with the leaver sorts it out (or prying apart the pads so I can get the fatter rotor in)
Anoyingly I bought a +20mm rotor from disco brakes, fitted a shimano 180mm rotor (previously 160mm) and it was a good 2mm too high even on its lowest setting (the addapter has slots rather than holes). Could probably have gone to 190mm!
I have mixed and matched many rotors in the past and all seemed to work fine.