Named after the the Cross Crusade in Portland Oregon, USA, PDX_clincher_1 the largest participant cyclocross series in the World, Clement's Crusade PDX the Portland airport code is an all-around performer with a particular love for mud. The center knobs are aligned to give you a fast roll on hard pack and pavement. Side knobs offer superior edge control so your bike stays under you in the curves, and the leading edge of the knob gives you extra traction coming out of corners. Since its introduction in 2010, the PDX has quickly become one of the most popular cross clinchers on the market. Side knobs offer superior edge control so your bike stays under you in the curves leading edge of the knob gives you extra traction coming out of corners The center knobs are aligned to give you a fast roll on hard pack and pavement. Front or Rear 75 psi