Brake pad touching tyre on road bike

[mickle]

Both are long reach brakes.
Both the original rear and new Miche rear measure approx 56-57mm drop (slight error/variation). Original fits fine front and back. Miche fits OK front, but not on the rear. It's about 5-6mm short of the rim.

If the brake doesn't have enough drop why is the front OK but not the rear? Considering that both rear drops measure up very similar.

Not similar enough obviously.

 

[RecordAceFromNew]

If the bike looks like the one below, then the further back from the rear stays the brake is the longer the drops need to be to hit the rim's braking surface. So while two sets of brakes might have the same caliper length, they can still have different reach.

A trick exists, if one wants to, mount brakes in front of the seat stays rather than behind to manipulate reach. There is no reason why it shouldn't work reasonably as long as one swaps the pads around, but there are complications for recessed nut systems and I can also understand it if one doesn't like the look of it... The obvious alternative solution is of course to measure what the potential difference needs to be and pick brakes that cover the range.