Swingarms

Rear swing arms

The rear swing arm is currently the most common form of rear wheel guidance on motorcycles. By the way, swingarms have not only existed since the 1950s, but are an invention from the early days of motorized two-wheeling (e.g. NSU 1911, Indian 1913). A rear swing arm, however, is demanding in terms of design and materials, and until the 1940s most motorcycle manufacturers shied away from the expense in comparison to the supposedly small benefit. After all, a suspension saddle can be comfortable, too.

As it is the case so often, the impetus ultimately came from racing. A rear swingarm keeps the wheel much better on the ground than a rigid wheel mount. Continuous ground contact simply transmits braking, drive and other forces better and more consistently, and contributes significantly to the controllability of the ride. Not just on the Isle of Man or Nürburgring, even when it's across country: the rider who wins is not the one whose Bates Baja-equipped rear wheel is in the air most.

What does a rear swingarm do?

The swingarm guides the rear wheel, ensuring that while it can move vertically in response to shocks from the road, it always remains level with the steering (head) axis. If the rear wheel were able to tilt sideways, the entire chassis would be stimulated to uncontrolled snaking movements with potentially fatal consequences for the driver. This is why it is also important to check the swingarm bearings regularly.

The swingarm keeps the rear wheel on the ground or on the road. Precisely because the swingarm allows the rear wheel to move vertically, it brings calm to the chassis. From a design point of view, a rigid frame is also a swing arm, only a very long swing arm whose swing arm axle is the front wheel axle. Road unevenness is thus transmitted to the entire motorcycle and the undamped movements lead to unsteady handling at higher speeds.

Even if the name suggests it, the swingarm does not really swing. The end of the swingarm that carries the wheel axle performs a circular (arc) motion around the pivot end which carries the swingarm bearings and serves as a fixed axle on the motorcycle frame. Speed, deflection, etc. of the movement are controlled by shock absorbers, still a pair of side-mounted stereo shock absorbers on most Harleys. On the latest Softail models and on the LiveWire, it's just a monoshock; on the classic Softails, there's a pair of horizontal shocks under the transmission.

Which Harley-Davidson models have a factory rear swingarm?

The K model series and its successor Sportster, i.e. K 1952-1953 and KH 1954-1956, and all XL... from 1957 onwards. Then the F model series 1958-up, i.e. FL, FLH, FLT, FX, Softail (FXST, FLST), Dyna (FXD...), FXR and Tourer (FL...). All current Harley-Davidson models are equipped with a rear swingarm.

Which swingarms and spare parts are available at W&W?

Our portfolio includes:

• Swingarm bearings for FLH and FX, Sportster, FXR, Tourer and Dyna.
• Swingarm axles for the models without rubber bearings, i.e. K models and Sportster up to 2003, FLH and FX with four-speed frame and Softail.
• Rear swingarms in original replacement quality for the FLH and FX with four-speed frame.
• For wide tire conversion performance swingarm models from Krüger & Junginger for Sportster and FXR.
• Shock absorber bolts and plates to protect against scratches.