Approach angle / departure angle

Front and rear approach angles are standardised vehicle data, so-called basic vehicle dimensions, as defined by the international standard ISO 612 of 1978. The size of the approach angle is, in addition to the ground clearance and the crossing angle, a determining parameter for the vehicle’s passability over the terrain.

Definition:

The approach angle is the largest possible angle between the base and a plane tangent to the tires, while no fixed point of the body lies between this plane and the base. Unless otherwise stated, the value of the approach angle is determined at the total vehicle weight.

α – approach angle; β – departure angle

Examples of approach and departuresangle sizes:

Ramp angle:

When it comes to assessing a vehicle’s off-road performance, another important parameter is the ramp angle or ramp breakover angle. This is the angle at which the vehicle crosses the ramp at slow speed without the chassis reaching the edge of the ramp. The determination of this angle is shown in the figure below and is determined by the wheelbase and ground clearance of the vehicle.

The crossing angle is only given for true off-road vehicles, you will not usually find this figure in the catalogue of a normal passenger vehicle.