The Larsen TT works on a vast number of terrains and conditions, which is why it is the favored tread of so many of our pro dual riders. The TT hooks up well because each small, square lug in the tread pattern is ramped to roll easily, yet tightly spaced so more knobs are making contact with the ground. Thus, the contact patch is effective on a wide variety of surfaces. eXCeption is a 120 tpi, 62a compound designed for lightweight cross country race use only