| Manufacturer | BSA/Triumph |
|---|---|
| Parent company | Triumph Engineering |
| Production | 1968–1975 |
| Predecessor | none |
| Successor | none |
| Engine | air-cooled 740 cc OHV transverse triple |
| Power | 58 bhp (43 kW) @ 7,500 rpm |
| Transmission | chain |
| Brakes | 1968-1971: 2LS drum/drum 1972-1975: disc/drum 1975: disc/disk T160 |
| Weight | 468 lb (212 kg) (dry) |
| Fuel consumption | 30-40mpg |
The BSA Rocket Three / Triumph Trident was the first true modern superbike and the last major motorcycle developed by Triumph Engineering at Meriden. It was badge-engineered to be sold under both the Triumph and BSA marques. The Rocket3 / Trident was part of Triumph's plan to extend the model range beyond their 650 cc parallel twins. Created to meet the demands of the USA market, the smooth 750 cc three-cylinder engine had much less vibration than the existing 360° twins. BSA fell into serious financial troubles,[1] but during the seven-year production run 27,480 Rocket3 / Trident models were produced.
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Although designed in the mid-1960s, the BSA Rocket3 / Triumph Trident engine had its origins in a 1938 parallel twin, the 500 cc Triumph Speed Twin of 1937 designed by Edward Turner. The 1938 Tiger 100 was a sports version of the Speed Twin; and in essence, the Trident three-cylinder engine is a “Tiger 100 and a half” (although the triple has a longer stroke that the "squarer" Tiger 100 engine). Following Triumph tradition, the OHV Trident engine has separate camshafts for inlet and exhaust valves.[2]
The three-cylinder design was started in 1962 by Bert Hopwood and Doug Hele. Meanwhile, test engineers developed the handling of the chassis by affixing lead weights onto a standard 650 Bonneville. The first prototype, P1, was running by 1965, and it seemed that Triumph might 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 ‘square tank’ look, not only robbed the prototype of its lean looks and added 40 lb (18 kg) of weight, but also delayed production by 18 months.[3] During 1966, a P2 prototype was produced with a more production-based Trident engine, with changed bore and stroke dimensions and improved cooling. Ultimately, Hele obtained 90 bhp (67 kW) from a Trident engine, leading to speculation that if development had speeded up in 1964, a 140 mph (230 km/h) British superbike could have been a reality in 1972.
Although the norm for British motorcycles was to have a wet multiplate clutch, the triple had a dry single-plate clutch. Although a "dry" clutch, it ran in the primary chaincase which contained an oilbath for the duplex primary chain.
The Rocket 3 / Trident were introduced in the summer of 1968, and were the first modern-era mass-produced multi-cylinder production motorcycles. Motorcycle Mechanics magazine exclaimed, "What a fantastic machine!",[4] but only four weeks later the much more sophisticated Honda’s CB750K was introduced. The British triple did not have the CB750's five-speed gearbox, overhead camshaft, electric start and disc brake; and in 1970 Triumph re-styled export versions with the original ‘classic’ look to try to revive sagging sales.
All the three-cylinder engines, and the Rocket 3 motorcycles, were produced at BSA’s Small Heath site, but final assembly of the Triumph Trident model was carried out at Meriden in Coventry. The major differences were the engine and frame: The BSA had an A65-style double loop cradle frame (with engine mounted at a slant) , while the Triumph had a Bonneville-style single downtube frame with vertical cylinders. Other differences were cosmetic. By virtue of their better riding position Triumphs sold better in the US despite BSA’s Daytona racing successes of the early 70. However sales did not meet expectations, and for the 1971 model year a fifth gear was added, creating the models BSA A75RV and Triumph T150V. BSA were having financial difficulties, and only some 205 five-speed Rocket3s were built before production of the BSA variant ceased. Production of the 5-speed Triumph T150V (with a front disk brake replacing the original drum) continued until 1974. For the 1975 model year the Trident was updated to the T160.
Tom Mellor set four new world speed records at the Bonneville Salt Flats in September 2008 with a 1969 Triumph Trident T150.[5]
Doug Hele continued to develop the engine, and in 1971 he joined with frame expert Rob North to produce the successful works Formula 750 racing machines. The most famous single bike was "Slippery Sam", a production class Trident prepared by Les Williams and his team. "Slippery Sam" won consecutive production TT races at the Isle of Man 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 this suggestion was not taken up. Further racing development in the USA was carried out at Duarte, California, under Racing Manager Dan Macias.
The prototype triples had a classic "Triumph look" with a rounded tear-drop tank. However, BSA/Triumph commissioned OGLE design company to create a "modern new look", this redesign leading to an 18 month delay. The result was a squarer fuel-tank and a less traditional BSA/Triumph look, and the BSA was given sloped cylinders and 'RayGun' silencers.
When, in 1968, the new triples were shown to the American BSA-Triumph management, they were disappointed. They knew Honda had a bike coming along, and felt the price of $1800 (£895)[6] was too high and technical details (like vertically-split crankcases and pushrod ohv valve train were far from "cutting edge". However, they acknowledged that the bike was fast, and a sales team led by BSA Vice-President Don Brown decided to launch of the bike by using a Rocket-3 to set some records at Daytona, (records which were only broken in 1971 by the Kawasaki Z1).
Brown felt that the BSA/Triumph triples needed a different look to succeed in the USA. A custom bike enthusiast, Brown engaged designer Craig Vetter to give the BSA A75 a customised face-lift, with a brief to make it sleeker and more balanced. (Brown's initiative was not authorised by BSA, and subsequently Vetter had problems getting his $12,000 fee, waiting two years to be paid). In due course, Brown revealed the Vetter project to Peter Thornton (President of BSA/Triumph North America). In October 1969, Vetter was called to display his customised A75. Thornton and the American officials were impressed, and Vetter's bike was then sent to the UK, but the bike arrived in England just as the BSA marque was about to be ended. Also, BSA-Triumph had set up a design facility at Umberslade Hall, and the design was seen as too "trendy" by chief designer Bert Hopwood; but after a positive public reaction to the design when it appeared on the front of US magazine Cycle World in October 1970, the UK managers changed their minds. They realised they had a large stock of obsolete BSA Rocket-3 parts that could now be turned into a premium-priced motorcycle. Engineer Steve Mettam was given the job of supervising production for the 1972/3 season; and the Vetter BSA Rocket3 became the Triumph X75 Hurricane. 1,183 engines were put aside for X75 production.
The prototype BSA Hurricane is on display at the AMA Motorcycle Hall of Fame museum in Pickerington, Ohio.[7]
In November 1974 the T150V was succeeded by the much-modified T160. Some of the changes were due to market response to the earlier Tridents, and some were to comply with American safety legislation. With forward-sloping cylinders (à la BSA Rocket3), electric-start and gearshift moved to the left hand side, NVT were making a last ditch effort to save large scale production and to reduce the gap between the Trident and the Honda CB750. The T160 was manufactured for little more than a year, with production ending in early 1976, after which NVT collapsed completely.[8] In total, 7,211 T160 models were built and sold in 1975.[9] The main new features of the T160 were as follows:
In December 1975, final batches 288 and 224 bikes were destined for Australia and the USA (respectively); but NVT diverted them to fulfil an order from the Saudi-Arabian police force. (Most UK police had by then switched to BMW motorcycles, but a few such as the Yorkshire Constabulary still used the Trident). Some 450 bikes were sent to Saudi Arabia, but the last 130 were still in the UK when the Saudis cancelled the order, so NVT Motorcycles decided to market them in the UK as the Triumph Cardinal. At the time the list price of a stock T160 was £1,215,[10] and although the "police accessories" were worth only £150, NVT listed the Cardinal for £1,522.80. In 1982, European dealers re-imported around 180 low mileage Tridents from Saudi-Arabia. These poorly-maintained and sand-encrusted machines were restored and sold as standard T160s.
The so-called "Quadrant" (aka "Quadrent") was a "bitsa" designed and built in secret by Doug Hele in 1973[11]. It was a 1,000 cc four-cylinder motorcycle made up from Trident parts (although the camshaft was sourced from outside the factory). Essentially, the fourth cylinder came from grafting on an extra middle crankcase unit; but since the primary chaincase and final drive sprocket could not be relocated, the fourth cylinder protruded on the right hand side of the bike. The top speed was reputedly 125 mph.
Quite why Hele developed this machine is something of a mystery, as the lopsided machine could never have reached production to compete with modern Japanese machines such as the Honda CB750 or the Kawasaki Z1. An inside view is that Hele's efforts in building the Quadrant was a waste of precious resources that (given NVT's precarious status) should have been directed elsewhere, such as getting the 900 cc triple "Thunderbird III" (below) to market sooner[12].
In 1975, an NVT prototype 900 cc triple, the T180 Triumph Thunderbird III, was developed but it did not reach production. NVT passed on the prototype to the Meriden co-operative which also chose not to proceed to production despite experimenting with installing the engine in their oil-bearing frame.
Severe financial and management problems at BSA, along with the rapid disintegration of the entire British motorcycle industry in the early 1970s, led to a government sponsored merger in July 1973 with Norton. However the re-structuring plans announced by the newly formed Norton-Villiers-Triumph Ltd. (NVT), resulted in a workers blockade of Triumph’s home Meriden works in mid-September. Production of the Trident was eventually transferred to BSA’s Small Heath factory in March 1974, but this lengthy disruption resulted in relatively few 1974 Tridents being produced.[13][14].
Bacon, Roy (1995). Triumph Twins and Triples. Niton Publishing. ISBN 1-85579-026-2.
Davies, Ivor (1991). Triumph-The Complete Story. The Crowood Press. ISBN 1-86126-149-7.
McDiarmid, Mac (1997). Triumph-The Legend. Parragon Publishing. ISBN 0-75252-080-6.
