Wiktionary
n. (context motorcycling English) The main component of the rear suspension of most modern motorcycles and ATVs; holds the rear axle in place while swinging vertically to allow the suspension to absorb the shock from bumps in the road.
Wikipedia
A swingarm, or "swinging arm" (UK), originally known as a swing fork or pivoted fork, is the main component of the rear suspension of most modern motorcycles and ATVs. It is used to hold the rear axle firmly, while pivoting vertically, to allow the suspension to absorb bumps in the road.
Originally motorcycles had no rear suspension, as their frames were little more than stronger versions of the classic diamond frame of a bicycle. Many types of suspension were tried, including Indian's leaf spring suspended swingarm, and Matchless's cantilevered coiled-spring swingarm. Immediately prior to and after WWII, 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 telescopic forks. In particular, sidecar motocross outfits frequently use swing arm front forks. The swingarm has also been used for the front suspension of 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.
Usage examples of "swingarm".
As the induction helmet automatically retracted, he rummaged through the swingarm pharmacopoeia for a trank and an antacid.
He peered briefly at the picked-over leavings of the snack foods on the other swingarm, made a face, and decided that he should eat a real lunch while he had the chance.
Reach-around swingarms held a bewildering variety of refreshmentsfrom beluga on toast points to Roderer Cristal on tapfor those occasions when the Adventure feed was directed to the screen, rather than the induction helmet that hung over the back like the cap on an electric chair.