Triumph Speed Twin

Infobox Motorcycle
left
name=Triumph Speed Twin 5T


aka=
manufacturer=flagicon|UK Triumph
production=1938-1940 1947-1959
class=
related=
wheelbase=convert|55|in|cm
length=
width=
height=
seat height=
engine=498cc 180 degree parallel twin OHV four-stroke
power=27 bhp @ 6300 rpm
torque=
dry weight= convert|365|lb|kg
fuel_capacity=
fuel_economy=
transmission=4 speed / chain

The Triumph Speed Twin 5T was a British motorcycle made by Triumph at their Coventry factory. Edward Turner, Triumph’s Chief Designer and Managing Director, launched the Triumph Speed Twin at the 1937 National Motorcycle Show. Costing £75, it was a 500 cc OHV vertical twin in a lighweight frame and the first truly successful British twin, setting the standard for many twins to follow. [cite web|url=http://vintagebike.co.uk/Bike%20Directories/Triumph%20Bikes/pages/Triumph-Speed-Twin-1938.htm|title=1938 Triumph Speed Twin|accessdate=2008-07-12] After World War II the Speed Twin was responsible for the survival of Triumph - and every major British marque offered a 500 cc twin designed on similar lines to the Speed Twin. [cite web|url=http://www.norphil.co.uk/2005/biker.htm|title=Triumph Speed Twin. 1937|accessdate=2008-07-12]

History

Edward Turner’s Triumph twin was a major turning point for the British motorcycle industry, as although a 500 cc parallel twin of medium capacity was not revolutionary, the 5T Speed Twin model was lighter than many contemporary singles with significantly more power and torque. Early models were only available in 'Amaranth red' with hand painted gold pinstripes to set off the chrome. Initially the one piece iron cylinder was secured with six studs which led to weakness, so these were replaced by eight studs."cite book | last = Kemp | first = Andrew | title = Classic British Bikes | publisher = Bookmart Ltd | date = 2001 | pages = pp. 90-91 | isbn = 1-86147-058-4 ] The two cyclinders were fed by a single Amal Type 6 carburettor and many features such as the transmission and clutch were straight from the Triumph single. "cite book | last = Remus | first = Tim | title = Triumph Motorcycles Twins & Triples | publisher = Motorbooks | date = 1997 | pages = pp. 9-12 | isbn = 0-7603-0312-6 ] Originally with girder forks, the sprung saddle was the only rear suspension as the Speed Twin had a rigid frame - also from the single cylinder production line. [cite web|url=http://auto.howstuffworks.com/1947-triumph-speed-twin.htm|title=Triumph Speed Twin|accessdate=2008-07-12] On the night of the 14th November 1940 the entire city of Coventry was destroyed by German bombs and the Triumph factory (which was working on an order of thousands of military specification 5T's) was completely wiped out, and all of Triumph's technical records, drawings and designs were destroyed. [cite web|url=http://www.ianchadwick.com/motorcycles/triumph/time02.html|title=Triumph Motorcycles timeline|accessdate=2008-07-13]

Development

After the war the recovery of Triumph at Meriden was largely due to the Speed Twin, which was developed in 1947 with telescopic forks and optional sprung rear. Further development led to a 'unit' engine and gearbox construction and styling changes including the 'Bathtub' fairings' and continued in production through to 1959. [cite web|url=http://www.british-car-auctions.co.uk/pdf/1959_Triumph_5TA_Twin_July_04.pdf|title=Speed Twin|accessdate=2008-07-12]

References

ee Also

* Triumph Motorcycles
* London Motorcycle Museum

External links

* [http://vintagebike.co.uk/Bike%20Directories/Triumph%20Bikes/pages/Triumph-Speed-Twin-1938.htm 1938 Speed Twin]
* [http://www.realclassic.co.uk/tri03122300.html Triumph Speed Twin review]