PBR or DBA Rotors

[MattSAU2XR8]

Hi Matt, sorry about the delay, I hadn't actually considered whether the anti-corrosion coating could be the problem, but what I actually did was sand into the iron making up the mating surface of the disc, so that it was no longer flat, but once bolted up the wheel would tend to bow the disc very slightly to sit closer to true. Very slow and long winded process which I'd not really recommend to anyone in hindsight. I think in future I'll just buy DBA or get a brake mob to check any other brands on the lathe before I fit them, particularly if using them with grippy pads which I suspect make them more likely to grab.