ive got a xr650r with dirt wheels and 17's for street fun on the way. my dillema is this.. to reduce swap over time from dirt to street, id like to use the same chain with different gearing. maybe someone out there has done this before. currently i have a 14 front on 48 rear for dirt but id like to put a 50 or 51 on the rear. i have a 42 for the rear for the street. would a 15/42 be able to work with the same chain as say a 13/50 for the dirt? any feedback with experiance would be great! my wife is tired of me spending to much time screwing the "red-head" as she calls the bike. i need to save time without compromising gearing by using the same chain. help me.... thanks!!!