Softail

The term softail refers to motorcycles and bicycles that feature a hidden rear suspension system with springs or shock absorbers to absorb bumps. Softail motorcycles give the appearance of having a hard-tail or rigid frame, normally with the shock absorbers or springs under the motorcycle and out of view.

The word "softail" is a registered trademark of Harley-Davidson motorcycles, coined with the release of the FXST Softail in 1984. Since then, the word has expanded to include other motorcycles with hidden rear suspensions as well as bicycles incorporating a rear suspension.

In Harley-Davidson motorcycles, the softail frame is designed to look like the rigid frame bikes of the past, while still offering the comfort of rear suspension. The shock absorbers are positioned along the axis of the motorcycle, tucked away under the transmission.

There are several Harley-Davidson models with the Softail frame, including the Softail Standard, Custom, Springer Softail, Heritage Softail, Heritage Springer, Night Train, Deluxe, Deuce, Fat Boy, Softail Slim, the Dark Custom Cross Bones, the Dark Custom Blackline and Breakout. With the exception of the Deuce, which has a 2 inches (51 mm) backbone stretch, these motorcycles have the same engine, transmission and frame and differ mainly in the choice of fork, wheels and accessories.

The Softail model line has included a number of choices in front fork configurations. Historically, they have also offered the Springer leading link forks that are reminiscent of the sprung front-ends that were used prior to the introduction of the Hydra-Glide in 1949. The FXST designation is used for 21" Front Wheel Bikes or when the Springer fork is used with a 21 inch wheel, while the FLST designation is used for 16" Front Wheel Bikes or when the Springer fork is used with a 16 inch wheel.

The Softail models do not have rubber-mounted engines. This led to more vibration in Evolution-engined Softails than in rubber-mounted Touring or Dyna models with Evolution engines. To compensate for this, current Softail models use a counterbalanced version of the Twin Cam engine instead of the regular Twin Cam engine used in the Touring and Dyna models.

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Wikipedia