Riley RMA

1945 to 1952
Overview
Production	1945–52 10,504 produced.
Body and chassis
Body style	4-door saloon
Powertrain
Engine	1.5 L Straight-4
Chronology
Successor	Riley RME

The Riley RM Series was the last automobile series developed independently by Riley. RM vehicles were produced from 1945, after the Second World War

For many years the Riley concern was family-owned, but during the 1930s it gradually ran into financial difficulties. In 1938 the Receiver was called in, and in the autumn of that year Lord Nuffield took the company over, for amalgamation into his group. The 1939 models were shortlived, and much influenced by Nuffield thinking. During the war all jigs and tools for these cars were destroyed, so Riley's postwar priority was to get a new car ready for sale.
The RM series of cars was prepared at breakneck speed by Harry Rush's team in Coventry, followed mainly traditional Riley thinking, and were an immediate and lasting success. The first of the range was announced in the late summer of 1945, only three months after the war ended, and deliveries began in the spring of 1946. Basis of the design was a new box-section chassis frame.

112.5in. frame being for the 1496cc engine. Both had torsion bar independent front all pre-war cars had beam front axles) and rack and suspension (a Riley innovation pinion steering. The engines were closely similar, but had different roots in Riley history; both were four-cylinder units, both had two camshafts mounted high in the side of the cylinder block, and both had opposed valves operating in part-spherical cylinder heads. Paradoxically, though they were long-stroke designs which did not rev very freely when standard, their breathing efficiency was very high indeed. At first the traditional Riley torque-tube transmission was a feature, but this was displaced by an open prop-shaft and a hypoid axle in 1952.

Bodies were built by traditional coachbuilt methods by the Morris Bodies Branch factory in Coventry. At first the only body available was a four-door saloon with sleek but rather old-fashioned styling, which included long swept wings and running boards. There was an upstanding Riley radiator, and the headlamps were only partially faired into the front sheet metal; differences in wheelbase were covered by short or long bonnets and front wings. Later, from 1948, a drophead coupe was also offered, along with a two/three-seater Roadster intended for the American market.

The RMA was the first post-war Riley. It used the 1.5 L engine and was equipped with hydro-mechanical brakes and an independent suspension using torsion bars in front. The body frame (not to be confused with the chassis) was made of wood in the English tradition, and the car featured traditional styling.The car was capable of reaching 75 mph (121 km/h). The RMA was produced from 1945 until 1952 when it was replaced by the RME. 

 Bore, stroke and capacity 69 x 100mm., 1496cc. maximum power 55bhp at 4500rpm.; maximum torque 761b.ft. at 3000rpm. No drophead model marketed.