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Triumph Speed Twin

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Triumph Speed Twin 5T
ManufacturerUnited Kingdom Triumph
Production1938-1940 1947-1959
Engine498cc 360 degree parallel twin OHV four-stroke
Power27 bhp @ 6300 rpm
Transmission4 speed / chain
Wheelbase55 inches (140 cm)

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 lightweight frame and the first truly successful British twin, setting the standard for many twins to follow.[1] 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.[2]

History

Triumph Speed Twin

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.[3]The two cylinders were fed by a single Amal Type 6 carburettor and many features such as the transmission and clutch were straight from the Triumph single. [4] 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.[5] On the night of the 14th November 1940 the majority of the city-centre 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.[6]

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 hub] rear suspension. In 1952, the Speed Twin caused controversy among traditional British riders as the generator and magneto were replaced with a Lucas alternator and battery/coil ignition system.[7] Semperlibre (talk) 10:58, 15 October 2010 (UTC)

Further development led to the 5TA with a 'unit' engine and gearbox construction and styling changes including the 'Bathtub' fairings' which continued in production through to 1966. [8]

References

  1. ^ "1938 Triumph Speed Twin". Retrieved 2008-07-12.
  2. ^ "Triumph Speed Twin. 1937". Retrieved 2008-07-12.
  3. ^ Kemp, Andrew (2001). Classic British Bikes. Bookmart Ltd. pp. 90–91. ISBN 1-86147-058-4.
  4. ^ Remus, Tim (1997). Triumph Motorcycles Twins & Triples. Motorbooks. pp. 9–12. ISBN 0-7603-0312-6.
  5. ^ "Triumph Speed Twin". Retrieved 2008-07-12.
  6. ^ "Triumph Motorcycles timeline". Retrieved 2008-07-13.
  7. ^ Robert Smith (March/April 2009). "1959 Triumph Speed Twin". Motorcycle Classics. Retrieved 2009-08-05. {{cite web}}: Check date values in: |date= (help)
  8. ^ "Speed Twin" (PDF). Retrieved 2008-07-12.

See also