The car, designed by Edmund Woodward Lewis (1870-1941) who had joined Rover from Daimler, had an unusual structure.

The backbone frame, without bump-compliance at the rear apart from the tyres, was suspended from the front axle at just one point by a pivoted transverse leaf spring which made no contribution to transverse rigidity, and thus the whole remaining car rested on just three points,[4][5][6] similar to the design of old, four-wheeled farm tractors.

[5] It had an unusual pedal control that changed over the valve operating cams to provide extra engine braking.

[4][6] When it was wished to slow the engine a driver's foot lever moved the cams first to reduce valve lift and then second, on further pressure, the valves are closed completely and the engine is effectively an air compressor slowing the rear wheels.

[5] At the engine's normal speed of 900 rpm it produced 8 horsepower (6 kW), the same number as its RAC tax rating.

Electric current is provided by an accumulator (battery) and a Bassée-Michel high-speed trembler coil and timed with a wide contact.

It has an engine driven bell-shaped clutch forced by a coil-spring on the output shaft to engage with a floating cast iron disc which transmits power to the three-speed gearbox.

The speeds provided by the gearbox are: Top gear is a direct drive through from the clutch to the rear bevel on the differential within the back axle's aluminium casting.

Ball cup swivel pins are mounted at each end with a slight set given the wheel axles.

[3] There are compression rods from the gearbox casing to stay each end of the front axle and minimise deflection by road shock.

Turning the car at a very sharp angle puts greater tension on the ignition or throttle control and the engine speed is upset.

[8] Since introduction modifications include removing the gearbox casing from its part in the car's backbone, improved gear changing and better access for the carburettor.

[9] Most of this series of Rover 8 cars seem to have had a very basic open two seat body with no windscreen or other weather protection.

Cooling was supplied through air scoops on the side of the bonnet and it was rumoured that after hard driving at night the cylinder heads could be seen glowing red through them,.

[10][16] Two cross-members of the frame supported at three points the assembled unit of engine and clutch and a three speed gearbox with reverse.

[15] Open two seater bodies with dickie seats were usual but an open 3 or 4-seater body was shown at the October 1922 Motor Show on a wheelbase 6 in (150 mm) longer at 94 in (2,400 mm)[18][19] and a few closed 2 seater coupés were also made from 1923 as well as light commercials.

[10] Optional extras included: non-standard colour £5, speedometer £7, side curtains to hood completely enclosing the body £3.

[15][21] The motoring correspondent of The Times reported in October 1922 the car's road manners were an agreeable surprise, it was astonishing how little one missed the other two cylinders.