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?
Have the Is>post mount adaptor machined down by 1-2mm.
You say the frame has "standard 135mm-spaced QR dropouts". I thought the standard OLN for road hubs was 130?
Can you try a non centre lock wheel in it, I had one which for some reason was really close to the calliper and mount on one bike but a six bolt disc and hub in the same frame was fine. Never figured out why and ended up putting the wheel in another bike where it fitted fine
Sorry just re read your op,, my post is probably not much help,as I just ended getting rid of the centrelock hub
You say the frame has "standard 135mm-spaced QR dropouts". I thought the standard OLN for road hubs was 130?
For non-disc that's right. Disc frames are the same as MTB at 135mm and 142mm.
Thanks Daffy - an interesting idea. I guess that would need to come off the outboard side in order to have the desired effect.
NewRetroTom - you are correct, road standard has long been 130mm, but road disc has seen companies going for 135mm QR and 142x12mm thru-axles, the latter of which seems to have finally settled as the standard on top-end performance bikes.
Kilo - yeah, will be giving the old XT/6-bolt wheels a spin this evening, but they're frankly horrible rims on there. And those DT Swiss R32s feel soooo good with a pair of 25mm Conti GP4000SII's on them. A really nice match for the frame.
Thanks Daffy - an interesting idea. I guess that would need to come off the outboard side in order to have the desired effect
Precisely. Much better than grinding your Ti frame. Ti work hardens when subject to grinding and the IS mounts are already pretty thin.
Or to keep it looking neater I guess I could just use a disc mount facing tool on the outboard side of the adapter holes, and only cut away a circular section close to the I.S. tabs.
In fact, I might just get busy with a file tonight. If I screw it up it's only the cost of a new adapter.
Great advice, thank you.
Are the disc bolts long enough to just use a disc spacer? Something like [img] 
[/img] or [img] 
[/img]
I'd probably swap the wheels for some handbuilts. White hubs and lairy graphics aren't really suited to a Ti frame.
A disc spacer would push the rotor further outboard, thus exacerbating the problem.
No idea about this frame but not all road disc are 135. Some stayed 130 but I suspect this has gone. Worth a measure?
R32s should come with CL/6-bolt -adaptors. Unlikely given that you tried a CL rotor on it, but perhaps they position the rotor differently from the Shimano ones?
Hubs ain't white Mr Taylforth, and the graphics are far from garish compared to other offerings.
http://road.cc/content/review/187454-dt-swiss-r32-spline-db
All fixed. Amazing what you can achieve with a file, hacksaw and *a lot* of patience. About 2.5hrs to take a smooth 1mm off. Fingertips still numb this morning but it's running beautifully!
[img] 
[/img]
Thanks again Daffy for the smart thinking.
Glad to hear it. I have about 2mm of clearance on my road bike so I can see how the problem happens.
A customer wanted to upgrade the wheels on their Whyte Stowe Ultegra, went for a pair of DT Swiss Spline R32 but couldn't use them as the rear disc was rubbing on the caliper mount.
We double checked that the adapters were in the right way round, tried some different disc sizes and mount options but nothing solved the problem.
We also tried a couple of different rear wheels (to make sure it wasn't a problem with the frame) and they both went straight in and spun freely.
Not just me then, that gives some comfort. They are a superb wheel, if they fit. Been running them on my gravel/adventure bike with tubeless 40C Maxxis Ramblers, and only borrowed them for this project. But think they suit the Equilibrium Ti even better. Need to decide whether to buy a different set for the gravel bike, or put them back there and get something for the Equilibrium. I guess I could just get another pair of the same...
Delighted I could help.