I wasn't really happy with the brakes so I decided to search for a good used ones. I found a good offer for the shimano 7800 BR and bought them.
I installed the front one without problems but the rear one is being a nightmare.
The problem: When I try to install the shimano brakes one pad reaches perfectly the rim but the other one (opposite side than the cable) does not reach the rim and collides with the rubber of the tire.
I can't find which model of brakes did the bike had, I can only see the brand written and it says promax. Here are some photos of the two brakes:
I can't see what is wrong with the new ones, that doesn't allow the right side to reach the rim, because the height of both seems to be the same. The width of the tyre (28) should not be the problem as the front one works perfectly There is a washer that was in the old brakes but does't make any difference for this problem if I put it or not.
Is there anything I can do to install this brakes in this bike?