Commence to hand rubbing or head scratching depending on your nationality! The new Challenge MTB tubulars (the 26 inch version is known as TIRE4415 while the 29 inch version goes by the name of TIRE79068) have started rolling into our warehouse and Bloggy can admit to feeling a twinge of curiosity about the much-talked-about MTB tubular ride quality. The Challenge tires feature a ridiculous 300(!) TPI super poly casing and weigh a willowy 540 grams. Now all I need is the $ for a pair of tubular wheels. Hellooooo plasma bank! Acquaint thyselves!