Hopper used to supply two versions of the 290 mm AU twin piston kit.
One version used a hub with a 8 mm offset to suit the offset used on Commodore stud pattern rims. There was also a standard offset hub that was supplied with Torana stud pattern.
This is a picture of the Hoppers 290 mm AU twin piston set with Commodore offset. You can just see the larger silver spacer between the caliper and the caliper adaptor.
The extra 8 mm offset gives better clearance between the caliper and the control arm on full lock but could be enough to cause tyre clearance problems if you were not replacing the rims.
So Hopper's no longer sell the kit with the Torana offset?
