Editing Swingarm (section)

{{Short description|Joins the rear wheel of a motorcycle to its body}}
[[Image:R51-plunger.jpg|thumb|[[Plunger suspension]] on a 1953 BMW R51/3]]

A '''swingarm''' ([[American and British English spelling differences|or]] swinging arm), originally known as a swing fork or pivoted fork, is a single or double sided mechanical device which attaches the rear wheel of a [[motorcycle]] to its body, allowing it to pivot vertically.  The main component of the rear [[Suspension (motorcycle)|suspension]] of most modern motorbikes and [[All terrain vehicle|ATVs]], it holds the rear [[axle]] firmly, while pivoting to absorb bumps and suspension loads induced by the rider, acceleration, and braking.

Originally motorcycles had no rear suspension, as their frames  were little more than stronger versions of the classic [[bicycle frame|diamond frame]] of a bicycle. Many types of suspension were tried, including [[Indian (motorcycle)|Indian]]'s [[leaf spring]] suspended swingarm, and [[Matchless]]'s [[cantilever]]ed [[Coil spring|coiled-spring]] swingarm. Immediately before and after World War II, the [[plunger suspension]], in which the axle moved up and down two vertical posts, became commonplace. In the latter, the movement in each direction was against coiled springs.

Some manufacturers, such as Greeves, used swingarm designs for the front forks, which were more robust than [[Motorcycle fork|telescopic forks]]. In particular, [[Sidecarcross|sidecar motocross outfits]] frequently use swingarm front forks. The swingarm has also been used for the front suspension of [[scooter (motorcycle)|scooters]]. In this case it aids in simplifying maintenance. In motorcycles with shaft drive, such as the [[Yamaha XJ650 Maxim]], the shaft housing forms the left side swingarm.

[[File:Yamaha XJ650 Shaft Drive.jpg|thumb|[[Yamaha XJ650 Maxim]] has a driveshaft forming the left swingarm]]