Originally Posted by
stephenboyd
Awesome, thanks for the info guys. Do you really think I would lose 3-5 mph going from a 25 to a 28?
I see no reason that such a small change would result in that type of loss. It's easy to blame slower speed on one factor, but many things can slow down a rider. No matter what type of tire you have, the amount of tread contacting the road is EXACTLY the same given the same tire pressure and weight of bike/rider. The only factors that are different are weight (a tiny effect in this case), rolling resistance (somewhat of an effect but not that great unless comparing a tire with smooth tread to one with knobbies) and tire flex (again at higher tire pressure not that bid a factor).