Originally Posted by
drbenjamin
It's started raining out here so I've swapped over to disc brakes up front. I noticed after an especially muddy ride that there is a ~2mm "unswept" dirty area on the outer edge of the disc; the pads appear not to be clamping all the way to the outer edge of the disc. Is this a problem?
What exactly are you describing here? Does the footprint of your brake pads actually
cover the outer edge of the disc (and yet it remains unswept)? Or do your pads entirely miss that peripheral area?
It is probably the latter, i.e. the pads don't even cover the most peripheral "ring" of the disc. This is actually perfectly normal. For example, this is exactly the way it is in a typical BB7 setup. About 1-2 mm next to the edge of the disc remains unswept by the pads.
Just make sure that the entire pad footprint falls into the "braking" area of the disc. As long as it is the case, it won't make much difference where exactly that footprint rides, closer to the center or farther from it.