[3] The revolutionary part of the Commando, compared to earlier Norton models, was the award-winning frame developed by a team led by former Rolls-Royce engineer Dr. Stefan Bauer designed around a single 2.25 in (57 mm) top tube.

The team to free the Commando from classic twin vibration problems and Bauer, with Norton-Villiers Chief Engineer Bernard Hooper and assistant Bob Trigg, decided that the engine, gearbox and swing-arm assembly were to be bolted together and isolated from the frame by special rubber mountings.

[9] The PR was built at the Norton Villiers Performance Centre at the Thruxton Circuit from 1970 - 1972,[1] mostly by former AJS rider and senior development engineer Peter Inchley.

The Plumstead models had a twin-leading-shoe front drum brake and the "cigar" silencers that were carried over from the Atlas.

Cylinder heads were individually chosen from stock castings and gas-flowed and squish bands machined into the combustion chambers.

[14][15] The standard Commando diaphragm clutch was retained, driving a close ratio 4 speed gearbox.

Testing had shown that a narrower front wheel improved lap times, and an alloy WM2 rim with a 360 x 19 tyre was fitted.

At that year's Isle of Man 750 Production TT, Williams came close to winning but ran out of petrol with sight of the finish line whilst leading.

[2] One of the first bikes was brought by an Italian team and on it their rider, Giuliano Ermanno, won the 1970 100 Miglia di Imola.