Everything stays in the frame
The job of the frame on every motorcycle, including any Harley-Davidson, is to connect the rear wheel with the front wheel with as much rigidity as possible - apart from the "predetermined hinge point" of the steering head. The frame must integrate the drive train and all related components: engine, transmission, oil tank, etc. , absorb vibrations and high loads from the ground (the road, offroad or wherever you are) and it should be corrosion resistant. If worst comes to worst it should be repairable.
Historical frames for Harley-Davidson motorcycles
The very first Harleys (1903, the wooden shed, you may remember ...) could not deny their constructive kinship to the then only 20 years old bicycles of the latest design ("safety low wheel", ~1880). The wheels were made just a little more sturdy and the frame tubes a little stronger. The frame was two-dimensional between the steering head and the seat tube and had only one loop around the motor. Harley-Davidson remained with this design, titled single loop in English, until 1935/1936. Only the frame for the 61" Knucklehead had two downtubes around the engine and from the following year the large side-valve engines (U, UL, ULH models) were also placed in this frame. By the way, these double-loop frames are usually meant when talking about rigid frames, although of course the previous frames also had a rigid rear wheel mount. The 750 Solo models had only one loop until they were discontinued in 1952, and on the Servi-Car the single loop was available until 1973. It worked, after all.
Buy a frame for the Harley
What is the plan? Building a chopper or bobber? Replacing the battered original frame? Both is possible with W&W Cycles' selection of replica Harley-Davidson rigid frames and swingarm frames for Flathead, Knucklehead, Panhead and Shovelhead from 1936-1984. Also available are rigid tail sections for Sportster model conversions, mounts for gas/oil tanks and toolbox, as well as repair and replacement parts.
Frames for Harley-Davidson motorcycles are traditionally made of steel and cast steel. Cast steel components are used where particular rigidity is required, i.e. at the nodal points such as the steering head, rear wheel axle, side car mounts, etc.. The joints are connected by a steel tube. This dichotomy in the material comes from the days when frames were still brazed instead of welded. The precisely drilled sockets of the castings also make it easier to fit the components together and minimize the necessary clamping points on frame jigs.
Have any questions?
Our service team will be glad to help out: Mondays - Thursdays 08:00-17:00 CET, Fridays 08:00-16:00 CET, Phone: +49 / 931 250 61 16, eMail: firstname.lastname@example.org