Off-road mobility

Extremely off-road special truck for trials , a motorsport variant

The off-road (equivalent to "road capability" and "off-road capability") is the property of a vehicle , to off-road surfaces on flexible and less grippy floors etc. to overcome and move obstacles, slopes, water crossings.

Certain cars such as off-road vehicles and SUVs , tracked vehicles such as tanks and bulldozers , excavators and certain cranes , as well as tractors , motorcycles , bicycles and certain work machines with their own drive such as combine harvesters or ride-on lawnmowers are specially designed for high off-road mobility . Precisely defined requirements for off-road mobility are often made when purchasing military vehicles. Off-road vehicles almost always have permanent or switchable or variable all-wheel drive , with off-road trucks several (or all) axles are driven (see drive formula ).

When exploring the moon , for example with the Soviet lunar rover Lunochod or the US Lunar Roving Vehicle used three times , as well as on Mars with the various Mars rovers , the vehicles were developed with a view to the highest demands on their off-road mobility.

Requirements for automobiles

The Willys MB , known as the Jeep , was developed as a US military vehicle during World War II . It is considered the archetype of the off-road vehicle .

The cross-country mobility depends u. a. from:

• the vehicle geometry and construction ( axle articulation , chassis and drive concept , ground clearance , ramp angle , slope angle , underbody protection , fording depth , center of gravity, wheelbase )
• the total reduction and the associated torque on the driven wheels
• the profile of the tires
• the possibility of manually or automatically locking the axle differentials and / or a central differential ( locking differential ) or automatically braking individual wheels without traction ( traction control through brake intervention or in combination with the option to intervene in the engine control )

Classification of cars

In the field of cars, a vehicle is considered to be off-road if it has - at least switchable - all-wheel drive, can negotiate a gradient of 30% and the vehicle geometry corresponds to certain minimum dimensions (for more details see " Off- Road Vehicle ").

motorcycles

Motorcycles designed for off-road mobility are referred to as enduro (street legal) or motocross (not street legal, only for racing or sports purposes ).

Cycles

Typical hardtail mountain bike, with telescopic suspension fork and disc brakes

In the 1960s, particularly off-road bikes were developed in the USA under the name Bicycle Motocross , or BMX for short, which are also used for off-road races, tricks and stunts in Europe and other continents. They usually have no gears, but a fixed gear ratio and relatively small wheels . From around the 1990s, mountain biking , a new type of bicycle at the time, developed into a popular sport . Mountain bikes are typically characterized by a robust construction, wide tires, very powerful special brakes and derailleurs with 18 or more gears. Initially without the suspension of the wheels , this type of bicycle was later increasingly equipped with telescopic forks and (more rarely) additional rear suspension.