While driving on the road, you have noticed that some trucks have wheels that lift. This is a common situation with large trucks. If you have been wondering what the reason is, the answer is very simple.
Trucks carrying heavier loads are equipped with multiple axles, because the lifting axle helps to distribute the weight of a particularly heavy load. But when driving without a load, the use of additional axles does not make sense, because more wheels in contact with the road means higher fuel consumption, but also tire wear. In this case, only the drive shaft is used. The whole process of lifting the wheels takes 25 seconds.
In recent years, some manufacturers, such as Volvo, offer a tandem drive axle with the possibility of lifting with 6 × 4 drive, which after lifting becomes 4×2. Volvo states that such a system saves up to 4% in fuel consumption and a turning radius of 1 m. Truck manufacturer Scania AB offers even better results, stating that its axle lift system saves up to 6% in fuel consumption and reduces tire wear.
Source: Scania AB
