The earlier version of the Cub used the Terrier's plunger rear suspension frame, but from 1957 this was updated to a more-modern pattern of rear swinging-arm with twin suspension units. The ignition points were positioned in a 'distributor'-type device on the crankcase behind the cylinder. A later development in 1963 was to site the points at a more conventional location on the end of the camshaft, accessed via a chrome cover below the base of the cylinder.
The Sports Cub designated T20SH featured slimline mudguards, no rear panelling or headlamp nacelle and with a higher compression ratio and other engine modifications was timed at 74 mph mean maximum by
Motor Cycle magazine.
Off-road versions produced with high level exhaust,
altered suspension and studded tyres,
were designated TS20 Scrambles Cub and TR20 Trials Cub.
The last model made was the T20 Super Cub, which, for economy of production cost, used a basic frame and other parts common to the BSA Bantam D10 including larger diameter wheels with full-width hubs.Launched in November 1966, it was discontinued in 1968, being briefly replaced by the 250cc TR25W 'Trophy', based on BSA's B25 'Starfire'.