Cyclo-cross bicycle

A cyclo-cross bicycle is a bicycle specifically designed for the rigors of a cyclo-cross race. Cyclo-cross bicycles roughly resemble the racing bicycles used in road racing. The major differences between the two are the frame geometry, and the wider clearances that cyclo-cross bikes have for their larger tires and mud and other debris that they accumulate.

Frame materials are selected with an aim to produce a lightweight, yet stiff and responsive frame. Low weight is prized for ease of carrying while running. A cyclo-cross racer may lift or carry his/her bike as many as 30 times in one 60 minute race, increasing the desire for a lightweight bicycle. Aluminum frames were popular in cyclo-cross bicycles long before they became commonplace on the road. Today the most popular material is aluminium with carbon fiber being popular at a professional level.

Cyclo-cross frames require clearance for slightly wider (generally 30–34 mm) tires and the debris and mud that is picked up by them. They are typically very simple, often eschewing bridges between the rear stays. Compact geometry frames with sloping top tubes are less common than on road bicycles due to the need to carry the bicycle easily on the shoulder. Top tube (rather than bottom bracket) routed derailleur cables help combat the build-up of mud. Some specialist cyclo-cross bikes also have a higher bottom bracket to aid clearance over rough ground; extra clearance could prevent toe clips from dragging while re-mounting after an obstacle. This is less common as clipless pedals have become the norm for cyclo-cross.

Typically, the frame geometry is a bit more relaxed than that of a road bike, not as upright in the seat tube, which allows for more stability in soft ground. Also, the wheelbase can be a bit longer, which provides a more planted feeling when using aft body weighting over rough terrain, and can help keep the rider's feet from contacting the front wheel during a tight turn.

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