Already posted this on road.cc forum, but I know I won’t get anything like as good advice over there…
I’m putting together a road disc braked bike with a Genesis Equilibrium Ti Disc frameset, DT Swiss Spline R32 wheels and Acor cable/hydraulic post-mount brakes (also sold and better known as Juin Tech R1) that come with 160mm 6-bolt rotors.
The frame has standard 135mm-spaced QR dropouts and an I.S. disc mount, to which I have attached a Shimano I.S. to post mount adapter (SM-MS-R160P/S). The brake caliper bolts nicely on top, no problems.
In order to fit the 6-bolt disc rotors to the centrelock wheels I have a pair of Shimano adapters (SM-RTAD05). All bolts together nicely, no issues.
The problem comes when I put the wheel in the frame, and the rotor is so close that it rubs the washers of the brake mounting bolts and the left hand brake pad, even when it is fully retracted and the caliper is seated as far out to the left as it will go.
The caliper design isn’t the problem, because the rotor is also rubbing on the caliper mounting bolt washer which has a position determined by the I.S. to post mount adapter and the frame itself.
I’m disregarding the thickness of the I.S. to post mount and 6-bolt to centerlock adapters as they’re both Shimano items and, well, they ARE the standard. I’ve also tested with a 160mm Shimano centrelock rotor and the problem is exactly the same.
Which means that either the I.S. mounts on the frame are sat a little too far inboard, or the rear hub is a little wider than most (the wheel is nicely centred on the axle). Putting an old Shimano XT 6-bolt hub and rotor in there the spacing is much better, which is pointing to the hub width as the culprit. Rotor face-to-frame distance is about 11mm on my DT Swiss wheels, and about 13.5mm with the old XT 6-bolt.
Has anyone had any similar challenges? The wheels ride beautifully, so I don’t really want to change those. Which means either getting the frame’s disc mounts faced (tricky with titanium, plus I think there’s a maximum of about 1mm that could be taken off) or finding some thinner 6-bolt to centrelock adapters. Which seems the likeliest option.
Any advice?