[1] The final development of the Velocette KTT, the Mk VIII KTT was introduced in 1938 at that year's Earls Court Show, and was the first motorcycle to use the now-conventional swinging-arm rear fork with a shock absorber unit (in this case, an oleo-pneumatic unit built by the Oleo Strut Co. of England).

Contact with the Oleo company led to several pairs of air shocks built for Veloce in 1936, for which the factory's racing rigid-frame racers (similar to the Mark VII KTT) were adapted with a swinging-fork rear end and bolt-on subframe for the seat.

The experimental first swinging-arms used an adapted steering head lug turned sideways, with the cup-and-cone bearings retained.

Production Mark VIII KTTs used a more conventional bronze bush and trunnion shaft pivot for the one-piece rear fork.

The first experimental swing-arm machines were raced by the factory in the 1937 season, and introduced as the Mark VIII KTT the next year, for sale to the public.