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BSA Rocket 3 / Triumph Trident

The BSA Rocket Three/Triumph Trident was the first true modern superbike and the last major motorcycle developed by the original (Triumph Engineering Ltd) Triumph company. It was badge-engineered to be sold under both the Triumph and BSA marques.

The Rocket3/Trident was the first-step development of Triumph Motorcycles' plan to move on from the basic vertical twin. The engine was to give the 750 cc power required by the US market while avoiding the vibration associated with the parallel-twin design and the bulk of a four-cylinder layout. This was the only part of the plan to come into production: the later four-cylinder Quadrant prototype only hints at what could have been later.

During its production run BSA fell into financial troubles and over the course of the official six year model run approximately 27,480 Rocket3/Tridents were produced - the exact number is unknown, as the factory at the end were very poor at keeping records. By comparison, a quarter of a million Honda Goldwings were manufactured during its first seven years.


1968 - 1975
3 cylinder


Although designed in the mid-1960s, the engine of the BSA Rocket3/Triumph Trident was based heavily on Edward Turner's legendary Triumph two-cylinder 500 cc Speed Twin of 1937 and the next year's sports model Tiger. Because of this, the three-cylinder Trident is sometimes known as the Tiger 100 and a half. However, when the bore and stroke are considered it is actually more like three C15 engines: the unit-construction T100 has a short stroke, unlike the triple's 67 x 70 dimensions. The pre-unit 500 was 63X80, as was "P1". When the rest of the engine layout is investigated, the T100 claim does look genuine. The separate camshafts from the Triumph engine are in evidence. This basic design was one of the most long-lived in motorcycling history, being used for over 40 years in Triumph's entire range of vertical twins, including the legendary Triumph Bonneville.

The three-cylinder design was started in 1962 by Bert Hopwood and Doug Hele. While design progressed, test engineers developed the handling of the chassis by loading lead weights onto a standard 650 Bonneville. With the first prototype (P1, which is now owned by the Trident and Rocket 3 Owners Club - TR3OC) running by 1965, it appeared that Triumph could have a machine in production by 1967. However, the decision to produce a BSA version with sloping cylinders and to employ Ogle Design to give the early Trident/Rocket3's their modern square look, not only robbed the prototype of its lean looks and added 40 pounds in weight but also delayed production by 18 months. During 1966 a P2 prototype was produced with a more production-based Trident engine, with changed bore and stroke dimensions and improved cooling. Later, Doug Hele obtained 90 bhp from a Trident engine, suggesting that if development had sped up in 1964, a 140 mph (230 km/h) British Superbike would have been a reality in 1972.

The first true Superbike

The Rocket3s/Tridents were immediately labelled superbikes when introduced in the summer of 1968: an apt description, since they were the first modern, multi-cylinder production motorcycles and amongst the very fastest then available. They were also labelled the best road bikes of the time - a label they had held for a mere four weeks when Honda's CB750K was introduced to compete against them in the important USA market, and at a lower price. Although the British triple did not have the 5-speed gearbox or electric start of the CB750K, it did have a great handling frame and so established a track pedigree through racing. To overcome US sales resistance, in 1970 Triumph re-styled export versions with the original & rounded look.

Although all the three-cylinder engines (and the Rocket Three) were produced at BSA's Small Heath site, final assembly of the Triumph Trident model was carried out at Meriden in Coventry. The major differences were the engine and frame: a double loop for the BSA and single downtube for the Triumph. The rest was essentially cosmetic badging and painting. Racing success allowed the Rocket3/Trident to continue with a four-speed gearbox, as models A75 and T150. By virtue of their better riding position Triumphs sold better in the US despite BSA's Daytona racing successes of the early 70. BSA's sold slightly better in the UK/Europe. However sales did not meet expectations, and in mid-1971 a fifth gear was added, creating the model Triumph T150V. With mounting financial pressure, very few genuine five-speed Rocket3s came off the assembly line before production of them ceased entirely. In 1973 a front disk brake replaced the original drum , resulting in the final form of the T150V.

Slippery Sam

Doug Hele's development work of the Rocket3/Trident in 1971, working with frame guru Rob North, produced Formula 750 machines that won everything in Europe/USA, even including the Isle of Man TT - most famously in its LP William' Slippery Sam. Trident "Slippery Sam" won consecutive production TT races five years running from 1971 through 1975. Bert Hopwood later recommended making a production version of the racing triple, producing 84 bhp (63 kW) at 8,250 rpm - but his suggestion was ignored, partly due to financial worries.

Racing development in the US was carried out at the Duarte, CA facility under Racing Manager Dan Macias. US BSA/Triumph dealers had agreements for access to factory race parts and due to difficulties in obtaining race frames from the UK, Dan built his own jig and the frames were manufactured by Wenco. The main differences from the factory North frames were TIG welding instead of brazed, flat plate rear engine mounts instead of built-up formed sheet and 4130 CrMo steel material. Dick Mann's win at Daytona in 1971 was on a US specification bike.

Triumph X75 Hurricane

When the Triples were designed, the original look was sleek and defined with a rounded tear-drop tank. However, to compete with the newer designs, BSA/Triumph decided to redesign the look using the OGLE design company. This created an 18 month delay and resulted in a squarer look and less traditional BSA/Triumph look - only the BSA was saved by sloped cylinders and 'RayGun' silencers.

When the Triples were launched to the American vice-presidents of BSA and Triumph in 1969, they were disappointed. They knew Honda had a bike coming along, and felt the price of $1800 (£895)was too high and technical details like vertically split crank cases ill-thought - which meant continuing oil leaks. However, they did respect the fact that the bike was fast, and the BSA team lead by US VP Don Brown (Vice President, General Manager and Director BSA, Inc. 1967 to 1969; reassigned as Vice President, National BSA Sales; resigned Jan 8, 1970); decided to set some records at Daytona with a stock A75 for launch of the bike - they were later only broken in late 1971 by the Kawasaki Z1.

Brown came home to America, and felt the bike needed a different look to compete. A custom bike enthusiast, he engaged later design guru Craig Vetter to give the BSA A75 a face-lift. Vetter flew to Nutley NJ for the job interview, and returned on an early BSA A75 with the brief to make it sleeker, more balanced and with a customised look.

Brown had no agreement from BSA group to undertake the redesign, told Vetter he would only get his fee paid as hours when the project was accepted for production, and swore Vetter to complete secrecy. Consequently Vetter had problems getting his $12,000 fee, but only because Brown paid external lawyers to create the contract, and was taking Vetter's expenses out of petty cash. Vetter rode the BSA A75 back to Illinois, and described it as a great bike, but like riding a board! In his 1,000-mile (1,600 km) ride, he tried a few designs sketched onto his own publicity postcards for his existing fairing business.

Vetter had two further problems to solve. He hated the triples twin exhaust, so he wound the pipes into one outlet and used a stock silencer that would be illegal in the USA market on noise regulations from December 1972 onwards - hence why the X75 was only produced for one year. The second problem was colour - he loved Yellow! But after painting the entire prototype Yellow, he hated it, and followed an AMA Bulletin to use ScotchLite reflective tape - the orange umber matched the Yellow ScotchLite.

Brown now had to reveal his project to his boss, Peter Thornton - President of BSA/Triumph North America, who he didn't get on with and had decided to resign from BSA as a result of their relationship. Thornton had heard about the design, and demanded details from Brown - or to sack him. Vetter was called from Illinois at the October 1969 Sales Conference, and spent 8 hours in a stockroom. Various people came by and looked in, with Vetter getting more nervous - until finally Thornton walked in. There was an audible gasp, and he then blurted out, "My God it's a Bloody phallus! Wrap it up and send it England!"

The bike arrived in England - just as BSA was about to declare bankruptcy! Also, BSA had set up a design facility at Umberslade Hall, and the design was seen as too trendy by chief designer Bert Hopwood.

It was only after an amazing reaction to the design when it appeared on the front of US magazine Cycle World in October 1970 that Norton-Villiers-Triumph realised it had a whole stock of scrap BSA parts that could now be turned into a premium-priced motorcycle, a young engineer Steve Mettam got the job of supervising production for the 1971 season. The Vetter BSA Rocket3 became the Triumph X75 Hurricane.

Vetter was paid his $12,000 dollars fee for his work in March 1971, but had a difficult time collecting it and it took several months. 1,183 engines were put aside for X75 production but the total number of machines finally produced is not accurately known.

The prototype BSA Hurricane, owned for a time by Craig Vetter, is now on display at the AMA Motorcycle Hall of Fame Museum in Pickerington, Ohio, USA.

Model T160

In November 1974, production of the T150V was ceased for the T160 model. The T160 was the result of a number of changes; some due to market response to the earlier Tridents and some due to legislative changes (mainly in the USA). With forward sloping cylinders (à la BSA Rocket3), electric start and gear-shift moved to the left hand side to comply with American safety legislation NVT made, in a last ditch effort to save large scale NVT production and reduce the gap between the Trident and the Honda CB750K. The T160 was produced for little more than a year, at which time NVT collapsed completely. The final batch of T160's came of the production line the week before Christmas 1975.


Model Years: 1975 (although some were made in early 1976 and the last bikes were finally sold in late 1977). Numbers: about 7,211 - the final 130 or so were sold as the Cardinal.

Significant Details

  • Forward-leaning cylinder layout derived from BSA Rocket 3 (to allow for larger air box)
  • Electric start
  • Five speed gearbox
  • Left-hand gear-change - USA requirement
  • Annular silencers - to meet lower USA noise-level requirement
  • Improved centre-of-gravity (frame/engine position, sloping cylinders, tank/seat unit)
  • Disc brakes front and rear
  • Redesigned instrument binnacle and handlebar switchgear
  • Improved 'traditional' styling