A tire changer is a machine used to help tire technicians dismount and mount tires with automobile wheels. After the wheel and tire assembly are removed from the automobile, the tire changer has all the components necessary to remove and replace the tire from the wheel.On a semi-automatic tyre changer, the head and locking plate is bolted and the handle mounted at the front/side of the column by the swing arm. In comparison, on a fully automatic tyre machine the whole rear column operates through pneumatics, using compressed air to manoeuvre the mounting head and locking it in place.In automotive suspension, a control arm, also known as an A-arm, is a hinged suspension link between the chassis and the suspension upright or hub that carries the wheel.The control arms are one of the core components of a suspension system and serve as the direct connection points between the front wheel assemblies and the vehicle's frame. The control arms allow a driver to steer a car while also guiding the wheels up and down with the road surface.