Off-road
There are various types of off-road motorcycles, also known as 'dirt bikes', specially designed for off-road events. Compared to road-going motorcycles, off-road machines are simpler and lighter, having long suspension travel, high ground clearance, and rugged construction with little bodywork and no fairings for less damage in spills. Wheels (usually 21" front, 18" rear) have knobby tires, often clamped to the rim with a rim lock.
There are specialized motorcycles for a variety of off-road motorcycle sports:
- Motocross — A short, closed off-road track with a variety of obstacles. The motorcycles have a small fuel tank for lightness and compactness. Long-travel suspension allows riders to take jumps at high speed. Motocross engines are usually single-cylinder two-stroke or four-stroke units, which vary in size from 50cc up to about 650cc. Motocross sidecar outfits have bigger engines, usually four-stroke and often twin-cylinder. Motocross bikes are also used in Freestyle Motocross.
- Enduro — A modified and road-legal motocross bike, having the addition of a horn, lights, effective silencing and a rear number plate. They compete over a longer course (which may include roads); and an enduro event will last between one day and six days.
- Rally raid, or Rallies — A special type of enduro bike but with a significantly larger fuel tank for very long distance racing, typically through deserts (e.g. Paris-Dakar rally). Engine capacities tend to be larger, usually between 450 cc and 750 cc.
- Trail —A trail bike is a dual-purpose bike, made for on-road and recreational off-road riding. A trail bike may resemble an enduro bike, but since a trail bike is not intended to be used for competition, it may be (i) less rugged, and (ii) equipped with more road legal equipment, such as indicators, mirrors and extra instruments.
- Trials — A specialized form of off-road competition testing balancing skills and precision rather than speed. For a trials bike, low weight and crisp throttle response power are the priorities, so a trials bike tends to have a small (125 cc to 300 cc) engine, two-strokes being common. During the trial, the rider stands on the footpegs, so a trials bike will have only a vestigial seat, or even no seat at all. Fuel tanks are very small, giving a very limited range. A trials outfit comprises a very light sidecar and an almost standard trials bike.
- Track racing — High-speed oval racing, typically with no brakes, no suspension, at most two gears, fuelled by methanol (not road legal machines). (Some types, such as speedway & grass-track bikes, are designed to take left turns only).
Read more about this topic: Dirt Biking