Rear Brake Upgrade 22v Discs update

[grash2]

Gandalf you are probably correct, the 2mm washer is not needed for the corsa disc 09 6801 10, for whatever reason the machine shop that tested the caliper and disc gave me instructions to use the 2mm washer

which later after fitment(without me having any doubts I installed the discs) I made the same calculation as you and got the same result as you did but I haven't yet refitted the calipers with out the washers, hence I am not sure 100% about it

corsa disc 09 6801 10 is not the best for the job for the reasons described on post 1 (clearance to caliper due to the 260mm diameter)

the rest are fine no washers and proper clearance from caliper

[Gandalf]

I fitted the Corsa discs, and confirmed it is absolutely necessary to use the 2mm spacers as indicated by grash2 and his mechanic. Without the spacer, the disc will rub on the caliper "backing plate" where it wraps around the front and holds the outside pad. I am using a slightly thicker spacer, at 2.75mm.
I updated my original question post as to not confuse anybody.