A change in the traction coefficient when loaded is of special significance in commercial vehicles due to the large weight differences between unladen and laden condition as a result of the high ratio of pay-load to unladen weight. The figure above shows the traction coefficients of double-axle trucks with a permissible total weight of 17 t against the vehicle weight.
The spread is reduced to a point for the permissible vehicle weight, since the permissible axle load is limited to 11 t by law. This limit is to be considered in all cases for a driven rear axle.