The larger tire is going to affect power in two ways. The larger diameter and the added weight hurt the power but it's really negligible. If you plan on ever pushing this machine even close to its potential, you're going to need new tires. My dealer blew 3 of 4 sidewalls in the factory duros. We have very rocky terrain here so we need a very strong tire.do those tires slow hurt the low end? or torque? i cant make a decision on new tires, if any.