Races almost universally consist of many laps over a short course, ending when a time limit is reached rather than after a specific number of laps or certain distance; the canonical length for senior events is one hour. Generally each lap is around 1.5-2 m and is 90% rideable. Races run under UCI rules must have courses that are always at least 3 meters wide to encourage passing at any opportunity, however sections of singletrack are common for small races in the USA and Great Britain. A variety of terrain is typical, ranging from roads to paths with short steep climbs, off camber sections, lots of corners and, a defining feature, sections where the rider may need, or would be best advised to dismount and run while carrying the bike. Under-tire conditions include asphalt, hardpack dirt, grass, mud and sand. Less emphasis is put on negotiating rough or even rocky ground with more stress on increased speed and negotiating different types of technical challenges.
Each section of the course typically lasts no longer than a handful of seconds. For example long climbs are avoided in favour of short, sharp inclines. Sections are generally linked together, or long straights broken up, with tight corners. This not only allows a standard length course to fit in a relatively small area, but also forces competitors to constantly change speed and effort. Accelerating out of corners, then having to decelerate for the next before accelerating again is a common theme.
Obstacles that force a rider to dismount and run with their bike or to "bunny hop" include banks too steep to ride up, steps, sand pits and plank barriers. Besides the start/finish area, these obstacles may be placed anywhere on the course that the race director desires. Several race directors have tried to limit bunny hopping by placing barriers in pairs or in triple (although under UCI rule no more than two barriers can appear in succession), however this hasn't stopped some of the best bunny-hoppers from getting over them. The regulation height for a barrier is 40 cm although this is treated as a maximum at smaller events. Plank barriers seem to be more common in the US than in Europe and UCI regulations only permit one section of them on the course.
Each section of the course typically lasts no longer than a handful of seconds. For example long climbs are avoided in favour of short, sharp inclines. Sections are generally linked together, or long straights broken up, with tight corners. This not only allows a standard length course to fit in a relatively small area, but also forces competitors to constantly change speed and effort. Accelerating out of corners, then having to decelerate for the next before accelerating again is a common theme.
Obstacles that force a rider to dismount and run with their bike or to "bunny hop" include banks too steep to ride up, steps, sand pits and plank barriers. Besides the start/finish area, these obstacles may be placed anywhere on the course that the race director desires. Several race directors have tried to limit bunny hopping by placing barriers in pairs or in triple (although under UCI rule no more than two barriers can appear in succession), however this hasn't stopped some of the best bunny-hoppers from getting over them. The regulation height for a barrier is 40 cm although this is treated as a maximum at smaller events. Plank barriers seem to be more common in the US than in Europe and UCI regulations only permit one section of them on the course.