Though cyclocross is a bit like mountain bike racing and a bit like road racing, the sport has unique requirements and has developed its own specialized equipment. Cross machines, old and new The traditional cyclocross bicycle evolved from the days when European racers would simply take their road bikes on the trail for cross-training during the winter. Today, the modern 'cross bike still resembles a road bike with its 700c wheels, double chainrings, and drop handlebars. Manufacturers offer purpose-built machines that are tough and light, and on a true 'cross course they are the fastest. By intent or accident, promoters familiar with mountain bike racing often select rough and technical courses that favor the fat-tire machines.
Bumpy trails slow down anyone lacking suspension or cushy tires.
Single-track limits passing. And, unless barriers are placed in pairs, mountain bikers can bunny-hop them while most 'crossers are forced to dismount. There is a bit of controversy brewing over the bike issue. USCF guidelines call for relatively wide, smooth courses that emphasize speed, dexterity, and running. Mountain bikes and mountain-bike courses trample these essential qualities.