fisrt of all, a rim brake is going to be more powerful than a disc break for the same breaking force because a rim brake is the basic equivilent of haveing a 26 inch rotor. secondly your rim break is on the back wheel which takes just a fraction of the power to stop vs. the front wheel. of course, this all goes out the window once you get that back rim wet and try to stop, then good luck

 Yeah, I did get it wet, Guess what... It was still great.