650 x 28 training/commutting tire. Just might be the answer for a little more cush and a little more puncture protection. The Terry Tellus is the first medium width tire ever offered in this size. The Tellus PT improves on the original Tellus by adding PT protection technology. PT provides a nearly inpenetrable layer of tire protection. Three times more puncture resistent than a kevlar belted tire of the same approximate weight.