1971 BSA A75 Rocket III
With an experienced team and a lot of data.
Although they had key differences and final assembly took place at different facilities, the Triumph Trident and the BSA Rocket 3 were essentially badge-engineered triples from the latter part of the two companies’ coexistence, and the Trident was actually the last major bike design undertaken by Triumph’s Meriden factory.
Triumph had been sold to Birmingham Small Arms Company (BSA) in 1951, but for many years there wasn’t much commonality between the two marques, in large part thanks to resistance by Triumph boss Edward Turner, who finally retired in 1964. It was only after this that Triumph could really plan to replace their aging parallel twins, although conservative management remained. The engineers at Triumph actually began developing a three-cylinder design in 1962, with origins going back to the 500 cc Speed Twin that powered the Triumph Tiger in the late 1930s.
Basically, the new triple was a 500 cc OHV twin with an extra cylinder for a 750 cc total. With a 67 x 70 mm bore and stroke, the 58-hp alloy triples in the final production versions allowed for a 120 mph top speed and featured less vibration than the old parallel twins. A triple was a departure for both Triumph and BSA, who would sell their own version, and development dragged on significantly longer than it needed to. Triumph Trident and BSA Rocket 3s were planned to be available by 1967, but it wasn’t ready until the following year, in part because of fundamental design changes to the BSA version.
The BSA and Triumph versions of the new triple were significant enough that these weren’t purely badge-engineered bikes. This in turn drove costs up, something a financially rocky BSA Group certainly didn’t need. The biggest difference was in the frame. Whereas the BSA had a double-loop all welded cradle frame, the Triumph had a single tube lug and braze downtube frame. The BSA also had its engine canted forward 15 degrees, while the Triumph had the engine mounted vertically. All engines were produced at BSA, but Triumph conducted final assembly of the Trident.
Styling for the Rocket 3/Trident was initially outsourced to Britain’s Ogle Design (the firm that styled the Reliant Robin), who gave the bike controversial “shoebox” tank. A cosmetic makeover in 1971 led to more conservative styling. 1971 also saw the end of Rocket 3 production, and in 1972 BSA’s motorcycle businesses merged with Norton-Villiers to become Norton-Villiers-Triumph. The Trident, meanwhile, would continue on until the 1975 model year, and would adopt several major changes. 1973-74 T150V models added a fifth gear and a hydraulic front disc brake, while the final T160 models had the forward leaning cylinders of the former BSA, front and rear disc brakes, electric start, a new instrument panel and switchgear, and both left-hand gearshift and annular silencers to comply with U.S. regulations.
Had the Rocket 3/Trident been developed more quickly and debuted earlier, it would have been a more important motorcycle, and while it was received enthusiastically upon its introduction, the Honda CB750 came out just a few weeks later and eclipsed it. At $1,800, the British bike was more expensive than the Honda, and the Japanese bike was more livable and reliable. The British bike was the faster choice, however, and became accomplished in motorsports. In the 1971 Daytona 200, BSA Rocket 3s came first and third, split by a Triumph Trident in second. A Trident nicknamed “Slippery Sam” also won the 750 cc production class at the Isle of Man TT every year from 1971-75.
Neither the Trident nor any product could save Norton-Villiers-Triumph, which collapsed in 1976. Some 27,500 Tridents were produced over a seven-year production run, and about 7,000 of these were the later T160s with the five-speed gearbox and electric start. The Triumph version is easier to find thanks to its longer production run and the fact that it sold better in the U.S. market than the BSA Rocket 3. For both versions, it must be noted that production occurred during a time of financial stress and labor dispute throughout BSA, and these bikes were not immune from build quality issues. Once sorted, though, they can be relatively dependable bikes and represent a faster, more interesting alternative to the more popular Honda CB750.