Bikes and Equipment
A classical cyclo-x bike looks very much like a road bike, but there are significant differences. The rear triangle and fork have more clearance to allow for wider tyres, and to help reduce mud buildup. Cross tyres are wider than road tyres, though the tyres a rider chooses will depend on the course and how wet, muddy or sandy it is. 25-35mm is more or less the common width range and have small knobs.
Cross bikes have cantilever brakes for mud clearance and control. The handlebars are road-style drops which reflects the sport's origins as off-season training for road racers. Historically the gear shifters were fitted to the end of the handlebars and known as 'bar-cons', but STI and Ergo have become very popular.
Cross bikes are usually somewhere in weight between a road bike and a light XC mountain bike they need to be as light as possible because of the significant amount of lifting and carrying of the bike that is required. Suspension is very rare as they would add too much weight. It's not uncommon to see a cross bike with only have one chain ring which is sometimes sandwiched between "rock rings". This allows for shorter chains, and therefore less chance of the chain bouncing off, as well as reduced weight from the elimination of the front derailleur and shifter. Pedals are often double-sided clip less SPD style, used with off-road shoes that sometimes have spikes or knobs under the toes to improve traction.
The courses used are usually a mixture of grass, dirt roads, relatively short tarmac sections, some sand, some mud or stream crossings and several forced dismounts and running sections. The natural obstacles in cross courses are often less severe than in mountain bike courses, but many mountain bike racers will say that cyclo-x is physically harder and more painful than mountain bike racing,..
For example, there are no long, rocky single track descents in cross, infact there are rarely any rocky sections. However, the descents might be significantly steeper, albeit shorter and on grass. Forced dismounts and running sections are the thing that really sets cross apart from other types of racing. .
There's a particular grace in the way an accomplished cross racer can approach a set of barricades at full speed, dismount and begin running while shouldering his or her bike, then jump the barricades, set down the bike, remount and pedal off. Remember that this all happens in continuous, fluid motion and there is very little reduction in speed. Other popular forced dismounts are short, very steep climbs that can't be ridden, or, sometimes, stair climbs.