With Christmas right around the corner I'm looking into to getting a set of rims. Instead of going for big flashy 18's or 19's I was looking into buying a set of Rota Slipstreams. Seen here. I really because of the lightweight. I want to know if going from a 16" rim to a 15" rim would affect my gearing? What size tire's should I get with the 15's? Or should I just say screw the difference of 4.4 lbs of rim weight between the two and get a set of 16's?