Many custom motorcycles use hardtail frames -- those without rear suspension.
There are several ways to classify motorcycles. One type of classification is motorcycle style, with categories such as cruisers or sportbikes. Another means of differentiating bikes is by their purpose -- some motorcycles are built specifically for long distance touring, others for off-road riding. The type of frame a motorcycle uses is another distinguishing characteristic -- there are two basic types of motorcycle frames: softail and hardtail. A softail frame includes two pieces, while a hardtail frame is built of a single piece. Motorcycles with hardtail frames have no rear suspension. Bikes with softail frames have a rear suspension system consisting of a swingarm and shock absorbers.
Background of the Harley-Davidson Softail
Technically, all bikes with a rear suspension system are softails motorcycles. In 1984, Harley-Davidson introduced a motorcycle with a new frame that concealed the rear suspension under the frame. That bike resembled the hardtail models, since the rear suspension wasn't visible. Harley dubbed the new motorcycle the "Softail," and launched a new family of motorcycles under that registered trademark name. The idea and initial development of the Softail was the work of Bill Davis, a rider and engineer living in St. Louis.
The Hardtail Frame
The hardtail, or rigid motorcycle frame, is one piece. The rear axle is attached directly to the frame. The lack of a rear suspension system gives hardtail bikes a distinctive streamlined look, often referred to as "the line." The line is the look of the frame rails extending from the gas tank to the rear axle. Another result of the lack of rear suspension on a hardtail motorcycle is the feel of the road through the frame -- every bump is transferred from the rear tire through the frame to the rider.
The Harley-Davidson Softail Frame
The two pieces of the Harley-Davidson Softail frame are connected by a pivot joint. The inverted cantilever rear end has a triangular assembly, which pivots near the seat of the motorcycle. The two shock absorbers are hidden under the engine. Because the rear suspension is hidden, the Softail frame maintains "the line" of the hardtail frame while softening the impact of the road on the rider.
The Hardtail Vs. The Softail
Similar looks aside, the biggest difference between a motorcycle with a hardtail frame and a Harley-Davidson Softail is the ride. The rear suspension of the Softail gives the rider a smoother ride and better handling. The rigid frame of the hardtail does give these motorcycles a slight advantage in cornering. Because the Softail has more parts -- the swing arm and shock absorbers -- there is a slightly greater cost of construction involved, and there are more parts that can wear out. Hardtail bikes are less suited for longer rides, since the motorcycle transfers the impact of every bump to the rider.
Tags: rear suspension, Harley-Davidson Softail, hardtail frame, rear suspension system, shock absorbers
