The Specialized Fast Trak Control Tubeless Mountain Tire has become synonymous with fast and lightweight tires that are able to handle the most technical courses and the most grueling conditions. This model redefines what was thought possible with a cross-country tread design. Specialized's Block-In-Block design uses a taller adaptable inner block to pierce the ground and claw for traction. The larger outer structure supports the inner block for additional speed, traction, support, and stable handling. Adding to this, the Fast Trak profile and knob spacing has been optimized for a wide variety of internal rim widths. The Control casing is our light and durable do it all XC construction. To top off this build, it uses Specialized's fastest rolling, race-ready T5 compound with excellent wear and tear protection.