Triumph GP and Trophy

Before World War 2, Triumph laid the foundation of the sporting parallel twin with its innovative Speed Twin. A decade later, the company's racing machines showed the high-speed potential of the format and confirmed its post-war popularity.

Triumph might have been expected to play a major part in the war but the bombing raids on Coventry damaged the factory and it was only able to resume limited production during 1942 at a temporary premises in Warwickshire. Triumph intended to concentrate its military production on a 350cc machine based on the Speed Twin but the only model built in quantity was a 350cc single.

Production of the Speed Twin and Tiger 100 resumed in 1945 and these models were soon modernised with telescopic forks. Shortly after, Triumph staff realised that the leftover stock of cylinder barrels from an auxiliary generator unit Triumph had built for the Air Ministry during the war offered the potential to create a lightweight, high-performance Tiger 100. Specifically providing a means of curing the overheating , to which highly tuned Triumph twins were prone.

Prototypes were prepared by Freddie Clarke, a pre-war record breaker and one was entered in the 1946 Manx Grand Prix, ridden by Ernie Lyons. The model achieved a famous win ahead of the Manx Norton. The race machine produced between 25 and 30% more power than the sports roadster and went into limited production. The generator-based engine was housed in a rigid frame with Triumph's telescopic fork. A form of rear springing was offered by the Turner designed sprung-hub which provided a limited degree of movement but it was also prone to rapid wear, which could result in severe handling problems.

Despite this, in 1948 the GP model, as it was called, won the Manx Grand Prix again and over the next few years made its mark in road racing. It was phased out in 1950, making way for race-kitted versions of the T100, but it had already become part of the Triumph legend.

There was another side to the story. In 1948 Triumph had entered an official team in the International Six Days' Trial in Italy and had created three special untra-lightweight twin machines which swept all before them and scooped the manufacturer's award.

In honour of the event Triumph launched a special model - the TR5 Trophy. A versatile, dual purpose machine, this used a single carburettor in place of the roadster's twin-carb setup and the engine was much more softly tuned. Club riders could use it as everyday transport and at the weekend remove the headlamp in minutes and be competitive in any off-road competition.

Triumph GP

• Years in production - 1948-50
• Engine - 180 degree parallel twin ohv four-stroke
• Bore and Stroke - 63 x 80mm
• Capacity - 498cc
• Power - 40bhp @ 6000rpm
• Carburettors - Amal Mk 6
• Tyres - 3 x 20in/4 x 19in
• Wheelbase - 53in

Triumph TR5

• Years in production - 1948-58
• Engine - 180 degree parallel twin ohv four-stroke
• Bore and Stroke - 63 x 80mm
• Capacity - 498cc
• Compression ratio - 6:1
• Power - 25bhp @ 6000rpm
• Carburettors - Amal Mk 6
• Tyres - 3 x 20in/4 x 19in
• Wheelbase - 53in
• Weight - 295lb
• Top speed - 85mph