Wheel traction plays a crucial role in pulling drawbar trailers. To prevent the tractor wheels from spinning when taking off from a stop, it is possible to mount a ballast weight on the rear of the tractor. Depending upon the expected payload of the trailer, the ballast can weigh up to several tons. Furthermore, the air pressure must also be set correctly in order to obtain proper ground contact with the tires.

Several different types of ballast weights are available and either fixed or removable ballast weights can be installed. Fixed ballast weights are mounted on the tractor permanently. Removable ballast weights can be parked in a separate rack and lifted / lowered by tractors with a hydraulic 5th-wheel boom.