The TR1 was introduced at Earl's Court Motor Show in 1952, and featured a dual carb version of the standard Triumph Vanguard engine. The car evolved into the TR2 and the TR3, which updated the body styling with a more rounded look. The spare was exposed on the back as well. This classic style became synonymous with British Sports Cars, and it’s influence can still be seen in today’s sports cars.
The TR4 was introduced in 1961 with a new, modern body styling and interior. Designed by Italian automotive designer Giovanni Michelotti of Turin Italy, the car featured a boxier more masculine look. Under the bonnet the Triumph TR4 was different as well. It featured rack-and-pinion steering and the transmission was fully synchronized on all gears allowing smoother shifting to power a larger engine.
Driver’s could option for an overdrive feature by Laycock de Normanville. It was electrically operated and could be selected for second, third, and fourth gear. The wet-sleeved engine was very convenient to work on as the cylinder and pistons were easily changed. This allowed the TR4 to compete under varying capacity rules.
This enable the TR4 be much more than just a good looking sports car. It competed well at SCCA hill climb rallies and won plenty of awards for TR4 owners.
The Triumph TR4 was upgraded to the TR4a, and later the TR5 (TR250) before transforming into the popular and successful TR6.