I have a pair of Kenda Caliente Pro's on a set of rims I bought off the classified board on here. I do not know the mileage of them, but they do not appear to be really worn. The rear tire has a few (I found 4 so far) very small nicks about 1/8" long. They cannot be seen from the inside of the tire. Two are on the center tread, two are closer to the apex of the sidewall. Does this warrant replacement of the tire, or is this normal? BTW, I am 6'6", 225 lbs, and ride in a lot of rolling hills.