The Riley RM Series is an executive car which was produced by Riley from 1945 until 1955. It was the last model developed independently by Riley prior to the 1952 merger of Riley's still new owner Nuffield, with Austin to form BMC. The RM series was originally produced in Coventry, but in 1949 production moved to the MG works at Abingdon. The RM models were marketed as the Riley 1½ Litre and the Riley 2½ Litre. There were four types of RM vehicles produced. All used Riley engines with four cylinders in-line, hemispherical combustion chambers and twin camshafts mounted high at the sides of the cylinder block. The RMA was a large saloon, and was replaced by the RME. Both used a 1.5 L (1496 cc) 12 hp (RAC Rating), developed before WWII. The RMB was a longer car: it was replaced by the RMF. Both cars used a larger engine, new in 1937, a 2.5 L 16 hp (RAC Rating) "Big Four". The RMC and RMD were limited-production cars, an open 2 or 3-seater Roadster and a 4-seater Drophead. The Riley Pathfinder was the RMH and the last saloon to have the Riley Big Four engine. Kestrel The RM was inspired by Riley Motors' successful and stylish pre-war 1.5 and 2.5 Litre Kestrel Saloons but the new cars featured a new chassis. The new chassis with its Riley "torsionic" independent front-wheel suspension incorporated the experience of the wartime years. The RM series was new because the patterns of dies for the old models were destroyed in the air raids on Coventry. Riley RMA The RMA was the first post-war Riley. It was announced in August 1945 with the news it would become available in the autumn. 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 . The RMA was produced from 1945 until 1952 when it was replaced by the RME. Riley RMB The 2.5 L (2443 cc) RMB was a lengthened RMA launched a year later in 1946. It used the 2.5 L (2443 cc) "Big Four" engine with twin SU carburettors, starting with 90 hp (67 kW) but increasing to 100 hp (75 kW) for