Cyclocross frames are frames specifically designed for the rigors of a cyclo-cross race. A Cyclocross frame can resemble a racing frame, the major differences between the two are the frame geometry and the ability to take Canti or Disc brakes (and on the odd reare occasion v-brakes) to allow wider clearances for their larger tires and the mud and other debris that they pick up. The aim is to produce a lightweight, yet stiff and responsive frame. Lightness is prized for ease of carrying while running. Aluminum frames were popular long in cyclo-cross bikes before they became commonplace on the road. Today the most popular material is aluminium with carbon fiber being a favorite at a professional level and steel and titanium being the top choice amongst riders searching for a smoother ride and a longer lasting frame. Cross frames can be built up into commuters or winter hack bikes as they have ample room for mudguards, and are often produced by manufacturers as a 'Cyclocross or Touring frame', their frames have plenty of clearance to allow for mudguards and the upright angles and fast handling suits city traffic.