I got 2 SM 17" rims for my WR426F 2002. What I do is put in 21/18 wheels every friday evening and 17/17 sunday evening as I drive my bike all week in the city. My problem is the front brake, as in the 17" rim I feel it's not good enough. So I want to change it to stronger brake system (bigger disk, better calipers?), but as I want to use the same disk for off and on-route it must not be too big. So I guess the question is what is the biggest disk suitable for off-route? What are your ideas fellas?