so I'm dealing with the image below on my bike. I have about 2mm of clearance at the brake bridge and slightly more at the fork, using an Enve 2.0. I'd like to squeeze a bit more out of the rear if possible. it looks like the pads on the 6800 calipers could go down another 5mm, making me wish the brake bridge had been welded higher. but oh well... there's certainly more room to go though as larger tires hit the calipers before they hit the bridge.
so far, I've tried Force 22, Tiagra 4500 and Ultegra 6800 calipers. the latter two offer the most room so far. what other options are out there that might offer more? maybe something from TRP?
