Cyclocross (sometimes cyclo-cross, CX or cyclo-X) is a form of bicycle racing. Races take place typically in the autumn and winter (the international or "World Cup" season is September-January), and consists of many laps of a short (2.5–3.5 km or 1.5–2 mile) course featuring pavement, wooded trails, grass, steep hills and obstacles requiring the rider to quickly dismount, carry the bike whilst navigating the obstruction and remount. Races for senior categories are generally between 30 minutes and an hour long, with the distance varying depending on the ground conditions. The sport is most popular in the traditional road cycling countries such as Belgium (and Flanders in particular), the Netherlands and the Czech Republic. Cyclocross blends aspects of mountain bike racing, cross-country cycling and criterium racing.
Cyclocross bikes are similar to racing bikes in that they are lightweight, and have narrow tyres and drop handlebars. However, they also share characteristics with mountain bikes in that they make use of knobbly tread tyres for traction, and cantilever style brakes for the extra clearance needed in muddy conditions. Bikes need to be lightweight because competitors frequently carry their bicycles to overcome barriers or slopes too steep to climb in the saddle. The sight of competitors struggling up a muddy slope with bicycles on their shoulders is the classic image of the sport.
Cyclocross riders may choose wider bars than road cyclists for extra control on rough terrain. A relatively tall, broad and open front-end setup gives you plenty of space to manoeuvre the front end of the bike beneath you and makes off-road trails fun to ride on a bike that could also conceivably be used for time-trial.