The motorcycle terminology presented herein addresses two-wheel single track vehicles, as well as three wheel variants. . Although two-wheeled, single track scooters and mopeds are similar to traditional motorcycles, they have many characteristics which differentiate them from motorcycles, and while some terms will apply, this Terminology addresses motorcycles specifically, unless otherwise noted. The terminology presents definitions covering the following subjects: dynamics and handling of single track vehicles, motorcycle categories and types, motorcycle crash dynamics and technology, and in-depth crash investigations, motorcycle design and components, systems, and equipment, motorcycle operation, operational environments and hazards, rider protective equipment including helmets and clothing, rider behaviors, motorcycle safety, competitive motorcycle events and the specialized motorcycles used those events, key national motorcycle-related organization, selected phrases commonly used uniquely by motorcyclists, and related performance measures and selected test criteria. NOTE: Motorcycle emission terminology does not vary from automobile emission terminology and is not unique and therefore not included in this report.
This Terminology is a primarily compendium of motorcycle engineering terms and phrases, and their definitions. The document was prepared to provide definitions for terms that are unique to motorcycling or, when the terms are used in reference to motorcycles, might have a definition that varies from general automobile industry usage. As many new technologies have been applied or adapted to motorcycle in the last fifteen years, they have brought their own vocabularies. The new technologies require formal definitions. While many older technical terms have evolve with the technology, current engineers, researchers, and others that investigate or document motorcycle statistics and data do not have a reference souce for the older terminology. Many terms have been extracted verbatim from SAE Standards, Recommended Practices, and Information Reports, and other sources as shown.