After the end of the war triumph bought back large quantities of unused military motorcycles they had made and repainted them in civilian colours. They also produced the Speed Twin, Tiger 100 and 3T models. These were identical to pre war models except that they were fitted with telescopic forks rather than girder forks. In 1948. Triumph's first trail bike (TR5: 500cc 'Trophy' TR5) is introduced. The engine was originally built by Triumph to power generators for the RAF in WW2: it has aluminum heads and barrels and is light, torquey and powerful. The following year the 650cc Thunderbird 6T was launched. Although basically a revamped, bored-out Speed Twin, 6T is designed to satisfy export (mostly American) market, offered as capable of a full 161 kmh/100 mph.

On September 24th 1951 Siegfried Bettmann dies leaving several bequests of Coventry, including his library of nearly 2,000 books. The company is sold to BSA for 2.5 million pounds. In 1954 Tiger 110 (T110) announced - very high performance, sporty version of the Thunderbird (42bhp compared to the Tbird's 34). It's Triumph's fastest motorcycle to date and is nicknamed the "Tiger-Bird" in the USA. The Wild One is released, starring Marlon Brando riding a 1950 Triumph Thunderbird 6T.

1959 saw the introduction of the 46bhp 650cc T120 Bonneville twin. The Bonneville was destined to become one of the greatest motorcycles of all time. Its name commemorated the world record run and the model was an immediate and long lasting success. 1961- TR6 Trophy introduced to replace the T110.It is essentially a Bonnie with a single carb. Steve McQueen rides a TR6 in movie "The Great Escape."