[3] Originally with a girder fork, the sprung saddle was the only rear suspension as the Speed Twin had a rigid frame – also from the single-cylinder production line.

[4] On the night of 14 November 1940 a German air raid destroyed much of the city centre of Coventry, and the Triumph factory, which was working on an order of thousands of military specification 5T's, was completely obliterated, along with all of Triumph's technical records, drawings and designs.

[6] After the war the recovery of Triumph at Meriden was largely due to the Speed Twin, which was developed in 1946 with a telescopic fork and optional sprung hub rear suspension.

The headlamp and instrument area was tidied up in 1949 with the Turner-designed nacelle, a feature retained until the end of the model line.

In 1953 the Speed Twin caused controversy among traditional British riders as the generator and magneto were replaced with a Lucas alternator and battery/coil ignition system.