Lift Axle

A lift axle is a way in which the axle can be raised so that its tyres aren't touching the road surface. This improves fuel economy, and reduces maintenance and tyre wear, although it increases road wear. The advantage of a lift axle is that it provides more scope for carrying heavier loads without having negative impacts when the truck and/or trailer are empty.
The lift axle's function is to raise and lower the axle with the compressed air used by the trailer. It improves the efficiency of the trailer operation by grounding and floating the tires. This is made possible through a sensor which perceive the weight burdened on the axle. Air will be automatically filled up with the air suspension when the sensor perceives that the cargo weight is lighter than the certain amount.