An axle bar is an object that serves as a type of dead axle called an axletree and is usually found on primitive wheeled vehicles like carts or wagons. A dead axle is a stationary axle that is not powered and does not turn. A spindle at each end allows for the mounting of wheels which turn around the axle bar. The term axle bar is becoming less common in English as the types of vehicles in which it is used fall out of favor and are replaced by powered vehicles. Some multi-axle vehicles, such as heavy trucks, use a combination of drive axles and dead axles. An axle bar is also the name of a fitness product used as a bar for lifting weights.
Primitive or low technology vehicles like wagons and carts differ in axle design from modern vehicles in that powered vehicles use a system of gears to provide power which turns the axle. The wheels in a powered vehicle are fixed to the axle which turns the wheels. A dead axle like an axletree is not powered. Traditionally, an axle bar is made from iron. An axletree made from other materials, such as wood, may be called by another term like axle beam.
A dead axle can be mounted in one of two ways. The axle can be affixed to the frame of the vehicle with the wheels spinning freely around it as the vehicle moves. Alternatively, the wheels can be affixed to the axle, which is mounted to the vehicle in such a way that the entire axle turns with the wheels. This arrangement is found on railroad cars for example and is called a wheelset. An axle bar or axletree is used in the first type of dead axle assembly.
While the term axle bar in the most technical sense refers only to a type of dead axle called an axletree which is fixed in place with rotating wheels, the term is sometimes used more loosely to refer to any shaft or bar of metal used as an axle. This rarely causes confusion however, as all axles, axle bars and axletrees serve similar purposes and work in much the same way, despite design differences.