Triumph's First Twin: Triumph 6/1

Triumph’s first production vertical twin was not the Speed Twin; it was Valentine Page’s Triumph 6/1.

Side of Triumph
The 6/1 did not sink without a trace. Comparing the specifications of the 6/1 and the later BSA A10, it is difficult to refute claims that the A10 is simply a 6/1 with a central flywheel and chain primary drive.
Photo By Mick Robinson