There are several different types of off-road motorcycles, also known as dirt bikes, designed and specialised for specific functions. For off road use they typically, when compared to road going motorcycles, have:
Light weight, small enginesLong
suspension travel and high ground clearance
Simple, rugged construction with little bodywork and no fairing
Large wheels with knobby tires, often clamped to the rim with
rim-locks Off road motorcycles are often specialized for a variety of off road
motorcycle sports, notably;
Motocross - A race over jumps - Thus these machines have small fuel capacities, extensive suspension travel, no road legal necessities (e.g. lights, indicators, instruments, etc), number plates for riding numbers, no passenger attachments, etc. Engines can be two or four stroke, typical capacities 250cc four stroke to 450cc four stroke (smaller for youth), as the weight and utility of the power of larger capacities is not needed.
Rally raid, or Rallies - long distance racing, typically through deserts for long distances. Road legal machine (like enduro) but with significantly more fuel. Capacities tend to be larger, around 450 cc to 660 cc (two or four stroke), an upper limit is often imposed for rider safety.
Trials - An extremely specialised form of competition focused on balancing skills and precision rather than speed. Thus low weight and quick power is the priority leading to small (125 cc to 300 cc) engines, often two strokes being used. Seats are unnecessary and affect the centre of gravity so they aren't installed (sometime they are jokingly referred to as banana bikes due to the lack of a seat). Fuel is kept to a minimum so range is very limited.
Track racing - High speed oval racing, typically with no brakes, no suspension, at most two gears, fueled by methanol (not road legal machines).
