Although it offers a unique driving experience, a motorcycle is a lot like a car. It has many of the same parts and mechanicals — an engine, wheels and tires, brakes, throttle, headlights, taillights, turn signals and a plethora of other bits. There are, however, some key differences between the two, one of which is a motorcycle’s swingarm.
You might have heard the term in conversation between riders about how a lack of travel broke their spine. (Hello, Ducati Diavel!) The term refers to a specific part of a motorcycle’s rear suspension setup that’s wholly unlike a car’s suspension. It’s a part important enough to warrant a proper breakdown.
(Disclosure: When Guides & Gear wanted to do a big series on motorcycle parts, riding methods, payload carrying, and a few other stories for two-wheeled lovers, Honda came through and sent us a 2021 Honda Ridgeline and CRF450RX to play with. Look for more stories soon.)
Given that motorcycles remain abstract items to much of the population—as well as new riders—The Drive’s Guides & Gear team is here to teach you the lingo. We’re going to bring you up to speed on the most important parts of a motorcycle and indoctrinate you into the rider community, so let’s dive in with everything you need to know about the swingarm.
What Is a Swingarm and How Does It Work?
A motorcycle’s swingarm is an H- or L-shaped suspension part that connects the chassis, or frame, of the motorcycle to its rear wheel. The swingarm is attached to a motorcycle’s chassis via a swingarm pivot bolt, which allows the swingarm and rear wheel and tire to move up and down with the undulations of the road—in conjunction with a shock and spring. This gives the motorcycle’s rear suspension travel, which is the distance between the top of the suspension stroke and the bottom at which the suspension can travel no more.
Are There Different Types of Swingarms?
There are! The H-shaped swingarm is the most common. This swingarm design connects to the chassis with the swingarm straddling the chassis, a pivot bolt, and shock and spring and the rear wheel straddled by opposing hubs. Most modern motorcycles use this design, including Honda’s CRF450RX race-spec dirt bike pictured here, as well as Kawasaki, Yamaha, Honda, and other sport, street, naked, and touring motorcycles.
The L-shaped, or single-sided swingarm design, is also pretty popular, although not as much as the H-shaped design. L-shaped swingarms feature the same chassis connection via a single pivot bolt and shock and spring but utilize only a single hub on one side of the rear wheel and tire. The result is that from the non-hub side, the rear wheel is an unbroken circle, resulting in a distinct (and some might say car-like) look.
Although most motorcycle manufacturers use a chain and sprocket for propulsion, some manufacturers actually incorporate a driveshaft into those single-sided swingarm designs, such as BMW and Moto Guzzi. Ducati and Aprilla, among others, use the design as well but with sprockets and chains.
How Does the Length of Your Swingarm Affect Performance?
Aside from suspension duty, your swingarm is a crucial performance component, and its length is particularly important. How long or short your swingarm is will directly affect how the motorcycle puts its power to the road, similar to how your sprocket’s teeth affect performance.
A short swingarm keeps the bike’s wheelbase compact and thus improves quick handling because there’s less real estate to move from one direction to another. A longer swingarm improves off-the-line acceleration because a longer wheelbase better distributes the weight of the motorcycle and engine power.
The length of the swingarm, which in part determines the wheelbase, also affects comfort and ride quality as it cruises over terrain and crumbling infrastructure.