A twistgrip is a handle that can be twisted to operate a control. It is commonly found as a motorcycle's right handlebar grip to control the throttle, but is sometimes found elsewhere, such as on a

bicycle A bicycle, also called a pedal cycle, bike or cycle, is a human-powered or motor-powered assisted, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A is called a cyclist, or bicyclist. Bic ...

as a gearshift, and in helicopters.

History

Roper steam velocipede 1868 The Standard Reference Work

Daimler Reitwagen color drawing 1885 DE patent 36423

The first use of the twist grip throttle control was on the

Roper steam velocipede The Roper steam velocipede was a steam-powered velocipede built by inventor Sylvester H. Roper of Roxbury, Boston, Massachusetts, United States sometime from 1867–1869. It is one of three machines which have been called the first motorcycle, ...

of 1867-69. Rather than a sleeve that rotated around the handlebar,

Sylvester H. Roper Sylvester Howard Roper (November 24, 1823 – June 1, 1896) was an American inventor and a pioneering builder of early automobiles and motorcycles from Boston, Massachusetts. In 1863 he built a steam carriage, one of the earliest automobiles. The ...

steam Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization ...

motorcycle's entire handlebar rotated, with a dual mode operation. When rotated forward it opened the throttle, and when rotated backwards it applied the spoon brake. '' Motorcycle Consumer News'' design columnist Glynn Kerr said that pioneering this technology was a point in favor of the Roper's precedence as the first motorcycle, in response to ''

Cycle World ''Cycle World'' is a motorcycling magazine in the United States. It was founded in 1962 by Joe Parkhurst, who was inducted to the Motorcycle Hall of Fame as "the person responsible for bringing a new era of objective journalism" to the US. ''Cyc ...

'' Technical Editor Kevin Cameron's position that the 1885 Daimler ''Reitwagen'' was more deserving because it used the more successful technology, internal combustion rather than steam. The design drawings of the ''Reitwagen'' depicted a twist grip speed control, also applying the brake when turned one way, but when turned the other way, it would have tensioned the

belt drive A belt is a loop of flexible material used to link two or more rotating shafts mechanically, most often parallel. Belts may be used as a source of motion, to transmit power efficiently or to track relative movement. Belts are looped over pulley ...

's idler pulley, applying power to the rear wheel in the manner of a

clutch A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). ...

. The actual working model, however, did not have the twist grip, belt drive, or brakes. Glenn Curtiss, unlikely to have been aware of the prior uses of the twist grip, used it in his 1904 motorcycle land-speed record machine, and is sometimes credited as the inventor of the device. Indian claimed in their advertisements, also for their 1904

models A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a measure. Models c ...

, to have invented the twist grip. Whether Curtiss, Gottlieb Daimler, or Roper were the true inventors, the 1904 Indian would be the earliest use of the device on a production motorcycle. Motorcycle throttles are spring-loaded to cut the engine power back to idling when the twistgrip is released. Formerly some motorcycle throttle twistgrips had a screw that could be screwed in to make the twistgrip stay still when released (e.g. for the rider to signal right turn), but a ruling from Brussels forbad that on safety grounds.

References

{{reflist, 30em, refs= {{Citation , last= Girdler , first= Allan , title=First Fired, First Forgotten , magazine=

, publisher= Hachette Filipacchi Media U.S. , issn=0011-4286 , location=Newport Beach, California , date= February 1998 , volume= 37 , issue= 2 , pages= 62–70 {{Citation , author-link=Glynn Kerr , last= Kerr , first= Glynn , date = August 2008 , title=Design; The Conspiracy Theory , magazine= Motorcycle Consumer News , location=Irvine, California , publisher=Aviation News Corp , volume=39 , issue=8 , issn=1073-9408 , page=36–37 , postscript=
Roper year 1869. {{Citation, last= Setright , first=L.J.K. , author-link=L. J. K. Setright , year= 1979 , title=The Guinness book of motorcycling facts and feats , publisher=Guinness Superlatives , isbn=0-85112-200-0 , pages= 12–18 {{Citation, url= https://books.google.com/books?id=ZdXaa3a2rtEC&pg=PA44 , title= Standard Catalog of American Motorcycles 1898-1981 , first= Jerry , last= Hatfield , publisher= Krause Publications , year= 2006 , ISBN= 978-0-87349-949-1 , page= 44 Motorcycle technology