Ride height / ground clearance

The ground clearance of a car is determined by the space between the ground and the chassis. The ground clearance is a determining parameter, for example, for the car’s ground clearance.

Vehicle ground clearance is one of the standardised vehicle data, the so-called basic vehicle dimensions, which are defined by the international standard ISO 612 of 1978.

Definition:

Vehicle ground clearance or ride height is the smallest vertical distance of the fixed point of the centre of the vehicle from the base. Unless otherwise stated, the ground clearance value is determined when loaded with the permissible total mass of the car.

světlá výška vozidla

vehicle ground clearance

The said centre section of the car is defined as the part between two planes parallel to the median longitudinal plane of the car, being the part defining 80% of the distance between the inner sides of the tyres. Another method of determining the ground clearance of a car prescribes the insertion of a circular arc between the inner tyre sidewalls and the lowest fixed point of the chassis, see figures. The lowest fixed points of the chassis simply do not include the brake parts, the outer parts of the wheel suspension, etc.

 střední část podvozku vozidla určení světlé výšky automobilu

Vehicle ground clearance and its effect on handling:

The ground clearance of a vehicle obviously affects the overall height of the vehicle and thus the position of its centre of gravity. Higher ground clearance means better ground clearance. On dirt roads, there is simply no risk of the underside of the vehicle colliding with the ground. On the other hand, a higher centre of gravity degrades the vehicle’s performance on asphalt. In fact, a car with a higher centre of gravity leans more and has less certain handling characteristics. Ground clearance is therefore a good tool for designers who want to develop several chassis versions, e.g. sports and off-road, on a common technical basis.

Example of different ground clearance for the same model:

Škoda OCTAVIA III 139 mm   (0 mm)
Škoda OCTAVIA III RS 127 mm   (-12 mm)
Škoda OCTAVIA III Scout 171 mm   (+32 mm)