page_title: Motorcycle fork
section_title: Girder
hierarchical_section_title: Motorcycle fork / Variations / Girder
caption_attribution_description: Photo © by Jeff Dean
context_page_description: A motorcycle fork connects a motorcycle's front wheel and axle to its frame, typically via a yoke, also known as a triple clamp, which consists of an upper yoke joined to a lower yoke via a steering stem, a shaft that runs through the steering head, creating the steering axis. Most forks incorporate the front suspension and front brake, and allow the front wheel to rotate about the steering axis so that the bike may be steered. Most handlebars attach to the top clamp in various ways, while clip-on handlebars clamp to the fork tubes, either just above or just below the upper triple clamp.
  The fork and its attachment points on the frame establish the critical geometric parameters of rake and trail, which play a major role in defining how a motorcycle handles and dives during braking. While the standard telescopic fork arrangement is found with few major differences among mainstream street motorcycles since the 1970s, historically there have been many variations, including trailing or leading link, springer, Earles, girder, and others, as well as non-fork steering such as hub-center steering.
context_section_description: One of the earliest types of motorcycle front suspension, the girder fork consists of a pair of uprights attached to the triple clamp by linkages with a spring usually between the top and bottom triple clamps. The design reached a peak in the "Girdraulics" used on the Vincent motorcycle. Girdraulic forks featured forged alloy blades for extra strength and hydraulic damping.
  While both may have an exposed spring near the triple clamp, a girder fork is distinguishable from a springer fork by the wheel being fixed firmly to the (usually a long diamond shape) upright. The pivot points are short links mounted to the top and bottom triple clamps. The spring is usually mounted to the girder and compressed against the upper triple clamp.
  Although girder forks are associated with early motorcycles, the British Ariel Ace, a modern sports motorcycle, has an alloy space frame and a matching girder fork. This Ariel girder fork is just as prone to brake dive as any telescopic fork, but is claimed to be more resistant to torsional twisting.
caption: 1934 Cotton with girder fork
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