Its time to get a new rear tire. The tire on the bike now is 170/80/15m/c stock new with the bike. I replaced the front a while back with a pirelli I picked up at the dealer and noticed a BIG difference in handling.My America is going in for the 25000 mile check up and I plan on having them install it then. My question is should I just pick up a tire through the dealer or can I save some change if I get it on line somewhere, and if so, where can I start. Is it necessary to stick with that size or do I have some room to 'move' so to speak.I am not looking to modify anything I just want a GOOD tire.