A very unique winter cycling discipline, Cyclo Cross (often shortened to just ‘cross’) bikes may at first glance look like road bikes but they are in fact quite different in a number of ways. Frames must have additional clearance so they do not clog up with mud, and to allow the use of wider, knobbly tyres. Knobbly tyres are a must for grip off road, particularly in slippery, muddy conditions that are common to winter cross racing, but must be much narrower than on a mountain bike and use the larger 700c diameter more commonly found on road bikes. Because of the tyres, and the need for mud clearance, the brakes must be different too. For this purpose cantilever brakes are common, or in some cases a smaller version of the mountain bike V-Brake is used. A second set of brake levers may also be used on the handlebars to give you greater access from all hand positions. Gear ratios are generally lower than on a road bike, as cross riding is generally in muddy conditions and riders may also encounter short, steep climbs during events.
In competition, bikes must occasionally be picked up and carried over obstacles or if a steep slope becomes un-rideable in slippery conditions, so they must be lightweight, and frame tubes are sometimes shaped to be more comfortable when placed upon a riders shoulder. They must be more robust than a road bike to withstand off road use. Wider handlebars are often fitted to improve handling, and tubular tyres, (tubs), are still preferred for competition as they can be used at very low pressure to provide maximum grip and comfort for the rider, but must first be glued very securely to the rim, with tub cement.
Aside from competition, cross bikes lend themselves very well to many other uses. Clearances for wider tyres, and the robust nature of the frames makes them ideal for touring, and for this reason many bikes are now including rack mounts as standard. There is also ample room for mudguards, which means that they double quite nicely as a winter training road bike, so investing in one can mean one bike to fulfil many roles, making it easier to justify the investment.