Editing Axle (section)

==Lift axle==
[[File:Triaxle dump truck 2005-10-06.km.jpg|thumb|upright=1.5|A dump truck with an airlift pusher axle shown in the raised position]]
Some dump trucks and trailers may be configured with a lift axle (also known as an ''airlift axle'' or ''drop axle''), which may be mechanically raised or lowered.  The axle is lowered to increase the weight capacity, or to distribute the weight of the cargo over more wheels, for example, to cross a weight-restricted bridge.  When not needed, the axle is lifted off the ground to save wear on the tires and axle, and to increase traction in the remaining wheels, and to decrease fuel consumption. Lifting an axle also alleviates lateral scrubbing of the additional axle in very tight turns, allowing the vehicle to turn more readily. In some situations, the removal of pressure from the additional axle is necessary for the vehicle to complete a turn at all.<ref>{{cite web|title=using a lift axle|url= http://www.thetruckersreport.com/truckingindustryforum/questions-from-new-drivers/42680-using-a-lift-axle.html#post418525 |work=Truck driver |publisher=The Trucker's Report|access-date=28 December 2011}}</ref>

Several manufacturers offer computer-controlled airlifts so that the dead axles are automatically lowered when the main axle reaches its weight limit. The dead axles can still be lifted by the press of a button if needed, for better maneuverability.

Lift axles were in use in the early 1940s. Initially, the axle was lifted by a mechanical device. Soon hydraulics replaced the mechanical lift system. One of the early manufacturers was Zetterbergs, located in Östervåla, Sweden. Their brand was Zeta-lyften.

The liftable tandem drive axle was invented in 1957 by the Finnish truck manufacturer [[Vanajan Autotehdas]], a company sharing history with [[Sisu Auto]].