chose the rim diameter on the performance tires available for your activity....for example for me, I would go 18" because the tires I run for track days and autocross do not come in a compatible size in a 19"...18's will be around for a while because it is the most popular size for the highest performance tire makers.......even the NEW 2015 Z28 gets down sized to a 18" wheel and tire combo from factory for performance
