Triumph never intended for their ‘C’ range unit twins to be competition mounts let alone trials bikes. The closest they came was with the TR5A/C launched in 1961 for one year and supposedly only available in the USA, then it became the T100S which became the T100C and gained weight, but the model was essentially a road machine with enduro capability.
For trials use Triumph had the Tiger Cub single which both their star men – John Giles and Roy Peplow – did great things on. The problem was Giles and Peplow were much happier on a twin, being of the rare breed which could make one work in trials. Both riders eventually persuaded the Triumph factory to allow them a twin and the Cub mantle went to Gordon Farley.
In actual fact the frame dimensions of the small unit twin are pretty close to the ideal for the feet-up game, however for Sixties tyres and sections the power produced by a twin engine wasn’t so ideal.
For the majority of riders a Triumph twin just couldn’t be made to find grip with the tyres available, add in that anyone wanting to experience the machines they saw John and Roy riding meant building it themselves. The issue is compounded by quite a few special parts being available only to factory team riders,
