The motorcycle terminology presented herein addresses two-wheel single track vehicles, as well as motorized three wheel cycles. 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. Likewise, some three wheel cycles may have some similar design features and share components with motorcycle, the dynamics and handling of three wheel vehicles differs from two wheel, single track motorcycles.
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 typically varies from general automobile industry usage. Many terms have been extracted verbatim from SAE Standards, Recommended Practices, and Information Reports, and other sources as shown.
Due to the uniqueness of motorcycles and the more active role the motorcycle rider has while riding, and the various potential operating environments, this Terminology was expanded to define terms and phrases of usage, rider safety and behaviors, and other areas that provide clarity for researchers and other not familiar with motorcycling. The definition provided within this document are directed and intended to be applied to certain two- and three-wheel motorized cycles only. Four wheel vehicles may use similar terms but typically other definitions apply.
The Terminology will serve a valuable function by providing a basis for improving motorcycle engineering terminology in many areas. SAE committees, and others, are encouraged to use its contents in the review of words and phrases used in their respective area, and to determine if additions or revisions might be made which could enhance comprehension and communication. This report is pertinent to such areas as vehicle design and development, the description of motorcycle, rider training and education, and the preparation of standards and regulations. Comments on specific terms and definitions can be directed to the SAE Motorcycle Technical Steering Committee.
This Terminology attempts to resolve many communication issues that exist for those who must research, investigate, regulate, educate, engineer, or communicate in the world of motorcycles and their components, or motorcycling or related activities. Some issues include:
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. And 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 source for the older terminology.
Some current SAE standards have terms defined in ways which are inconsistent with the same terms defined in a different standard.
Within the motorcycle industry there has not been a single source for defining common terminology. As a result, regional manufacturing and development has led to multiple terms for near identical definitions.
This Terminology compiles terminology from a myriad of sources into a single reference document. As language, technology and usage evolves, this Terminology will be reviewed and upgraded as necessary.