I've had my commuter out of action for a few weeks (not that it matters a great deal during lockdown
) due to a rubbing front caliper. I had tried all the usual culprits so ordered some new cup and cones washers to see if that helped. They arrived yesterday, and this evening I got a chance to play again so popped them on. It made a slightly difference but still rubbing 🤔
The caliper is almost brand new, a Hope RX4 post mount 4 piston jobby, and has rubbed since it was fitted. Cracking piece of kit when working and since I have several sets I know they're usually reliable and easy to adjust. With that in mind I removed it again and inspected the fork posts a bit more closely. This revealed the mounting surface wasn't perfectly square to the rotor surface, no wonder I couldn't get them set up
I don't own the proper kit for re-facing them but I do own several files and a calibrated eye so I set to squaring them up
10 mins later and after a few trial fits I had the caliper refitted and the rotor spinning unobstructed
Hopefully I'll get a chance to pop in to work at some point soon to test it all out, but I'm not expecting any problems now its all aligned properly.
I can't work out why the old SRAM calipers didn't rub, unless the mounting surfaces on those were wonky in the opposite direction and countered it
Maybe they did rub and I just didn't notice - it's a dynamo hub so theres a bit of drag from the front anyway but I can't imagine I've not noticed it in the ~2000 miles I ran the old brakes