The term softail refers to motorcycles and bicycles that feature a moveable rear suspension system with springs or shock absorbers to absorb bumps. On motorcycles, the shock absorbers or springs are hidden underneath out of view to give the appearance of a hard-tail or rigid frame. 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 hardtail 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, and the Dark Custom Crossbones. These motorcycles have the same engine, transmission and frame with the exception of the Deuce, which has a Template:Auto in backbone stretch, but differ in the choice of fork, wheels and accessories.
The Softail range is the only range of Harley-Davidson motorcycle that offers a choice of front suspensions within the range. The Sportster and Dyna models use the thin X-type telescopic forks, the VRSC models use a fork unique to the VRSC line, and the Touring models use the fat FL-type telescopic forks. Softails models may use either the X-type or the FL-type, or may use the Springer leading link forks that have only been used on Softail models so far. The FXST designation is used when the X-type fork is used or when the Springer fork is used with a 21 inch wheel, while the FLST designation is used when the FL-type fork is used 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.
Bill Davis, an avid Harley rider and engineer from St. Louis, Mo. designed the softail in the early 1970s. According to Greg Field on page 242 of the chapter "Father of the Softail" in the book "The Harley Davidson Century", published by MBI Publishing (2002), Mr. Davis contacted Willie G. Davidson in 1976. Furthermore, in his book, "Harley Davidson Softail", Field says that Davis sold over his "sub shock wide glide prototype" to Harley Davidson in 1982. In 1984 Harley Davidson began to manufacture a revised version of the Davis softail design.
Other motorcycles with softail rear suspension include:
- Cruelworld Softail at Von Dutch Kustom Cycles.