Riley RM Series
1951 Riley RMA
Overview
Manufacturer	Riley Motors
Production	1945–55
Body and chassis
Class	Executive car (E); compact executive car (D)
Body style	4-door saloon 2-door open 2 or 3-seater 2-door 4-seater cabriolet
Layout	FR layout
Dimensions
Wheelbase	1.5 L cars – 112 in (2,845 mm) 2.5 L cars – 119 in (3,023 mm)
Length	1.5 L cars – 179 in (4,547 mm) 2.5 L cars – 186 in (4,724 mm)
Width	63 in (1,600 mm)
Height	59 in (1,499 mm)
Chronology
Predecessor	Riley Kestrel body and 12/4 1½-litre engine or 16/4 2½-litre Big Four engine
Successor	Riley Pathfinder

The Riley RM is a series of executive cars and compact executive cars that were made by Riley Motors from 1945 until 1955. They were the last models developed independently by Riley before its parent company, Nuffield, merged with Austin to form BMC. The RM series was produced in Coventry until 1949, when production moved to the MG works at Abingdon. Until 1952, models were marketed as the Riley 1½ Litre and the Riley 2½ Litre.^[1] the term RM has been used retrospectively to encompass models produced before 1952.

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 (1,496 cc) 12 hp (RAC Rating), developed before WWII.

The RMB was a longer car, and 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 was the last saloon to be built with the Riley Big Four engine.

The RM was inspired by Riley Motors' successful and stylish pre-war 1.5 and 2.5 Litre Kestrel saloons, but with a new chassis, which with its Riley "torsionic" independent front-wheel suspension incorporated the experience of the wartime years.^[2]

The RM series was a new design, because air raids on Coventry destroyed the patterns of dies for the pre-war models.^[3]

Riley RMA
1952 RMA
Overview
Production	1945–52 10,504 produced.
Body and chassis
Body style	4-door saloon
Powertrain
Engine	1.5 L Straight-4 as for 2.5-litre Big Four but bore 69mm by stroke 100mm and bhp 60 @5,300 rpm[4]
Chronology
Predecessor	Riley 12/4 and Riley 12
Successor	Riley RME

The RMA was the first post-war Riley. It was announced in August 1945 with the news it would become available in the autumn.^[5] 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.

Wikimedia Commons has media related to Riley 1½ RMA saloon.

Riley RMB
Overview
Production	1946–52 6,900 produced
Body and chassis
Body style	4-door saloon
Powertrain
Engine	2.5 L Straight-4
Dimensions
Wheelbase	119 in (3,023 mm)[6]
Length	186 in (4,724 mm)[6]
Width	63.5 in (1,613 mm)[6]
Height	59 in (1,499 mm)[6]
Chronology
Successor	Riley RMF

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 1948 with a 95 mph (153 km/h) top speed.

The wheelbase was 6.5 in (165 mm) longer and the overall length was a full 7 in (178 mm) longer. The RMB was replaced by the RMF for 1952.

The RMB 2½ Litre models have light blue bonnet and bootlid badges, differentiating them from the RMA 1½ Litre models which have dark blue badges.^[7]

A car tested by The Motor magazine in 1949 had a top speed of 90 mph (140 km/h) and could accelerate from 0–60 mph (97 km/h) in 16.8 seconds. A fuel consumption of 19.6 mpg_‑imp (14.4 L/100 km; 16.3 mpg_‑US) was recorded. The test car cost £1224 including taxes.^[6][8]

Wikimedia Commons has media related to Riley 2½ RMB saloon.

Riley RMC
1949 RMC
Overview
Production	1948–51 507 produced
Body and chassis
Body style	2-door open 2/3-seater
Powertrain
Engine	2.5 L Straight-4

The RMC (Roadster) was an open 2-door, single bench seat, 2/3-seater version of the RMB, with a large rear deck area and fold-flat windscreen. Announced in March 1948, it was delivered to Geneva just too late to be exhibited at the Geneva Motor Show. Primarily designed for the North American export market, it was normally built with left-hand drive, with the gear change lever on the steering column. The bonnet and radiator were lowered and the bonnet catches were arranged to be operated internally. Extra over-riders were fitted to the bumpers and the fuel tank was enlarged to 20 imp gal (91 L; 24 US gal).^[9]

Eighteen months later, in September 1949, Riley announced future production would include a small quota of cars with right-hand drive. Riley attributed that to a slight increase in the supply of steel.^[10]

Instead of side windows it was supplied with flexible celluloid-glazed side curtains with a hole for hand signals and, when deployed, flimsy synthetic roofing over a light metal frame. It shared that car's 2.5 L 100 hp (75 kW) engine, and could reach 100 mph (160 km/h).^{[citation needed]}

Just over 500 were built from 1948 until 1951.^{[citation needed]}

Both the back and front of the car bear a remarkable likeness to a 1934 Ford V8.

Wikimedia Commons has media related to Riley 2½ RMC 3-seater roadster.

Riley RMD
1950 RMD
Overview
Production	1949–51 502 produced
Body and chassis
Body style	2-door cabriolet
Powertrain
Engine	2.5 L Straight-4

The RMD (drophead) is a traditional 2-door cabriolet, and was the last Riley cabriolet. It uses the same 2.5 L 100 hp (75 kW) engine as the RMB, on which it was based. Just over 500 were produced between 1949 and 1951.^{[citation needed]}

This model was first displayed in October 1948 at London's Earls Court Motor Show.^[11]

A cabriolet has fixed sides to its roof, called cant rails, and a folding top that remains attached to the vehicle. In a cabriolet like this Riley RMD the tops of the fixed sides, the cant rails, the beams over the side-windows, may be folded along with the top. While the hood is being opened or closed the heavy cant rail beams are supported by exterior hood irons. The hood irons, an elongated S-shape when the roof is up, may be seen at each of the roof's rear quarters. A more English name for a folding cover or canopy of a (horse drawn) vehicle enabling the occupants to be seen clearly is a "head" or for motor vehicles in the mid-20th century drop head.[12]

Wikimedia Commons has media related to Riley 2½ RMD 5-seater drophead coupé.

Riley RME
1953 RME
Overview
Production	1952–55 3446 produced
Body and chassis
Body style	4-door saloon
Powertrain
Engine	1.5 L Straight-4
Chronology
Predecessor	Riley RMA
Successor	Riley One-Point-Five (1957)

Launched in 1952, the RME was an improved RMA.^[13] It uses the same 1.5 L four-cylinder engine, and has a fully hydraulic braking system. The body has a larger rear window, with curved glass. To improve acceleration, the rear axle ratio was changed from 4.89:1 to 5.125:1.^[14]

When the 2.5 L (2443 cc) RMF ended production in October 1953, many details of the RME were revised. These included dispensing with running boards, and introducing entirely re-shaped front mudguards.

The RME was discontinued in 1955. It was succeeded in 1957 by the Riley One-Point-Five, which had been designed as a replacement for the Morris Minor, but never launched as such. This is a BMC design, unrelated to the RM series. It is much shorter than the RME, and was also badge-engineered as the Wolseley 1500, and in Australia as the Morris Major and Austin Lancer.

An RME tested by The Motor magazine in 1952 had a top speed of 75 mph (121 km/h) and could accelerate from 0 to 60 mph (97 km/h) in 29.5 seconds. A fuel consumption of 24.2 mpg_‑imp (11.7 L/100 km; 20.2 mpg_‑US) was recorded. The test car cost £1,339 including taxes.^[14]

Wikimedia Commons has media related to Riley 1½ RME saloon.

Riley RMF
1953 RMF
Overview
Production	1952–53 1050 produced
Body and chassis
Body style	4-door saloon
Powertrain
Engine	2.5 L Straight-4
Chronology
Predecessor	Riley RMB
Successor	Riley Pathfinder

The RMF replaced the RMB in 1952. It has the same 2.5 L Big Four engine, plus mechanical updates shared with the RME. RMF 2½ Litre models have light blue bonnet and boot-lid badges, whereas the RME 1½ Litre models have dark blue badges.^[7] In 1953 the RMH Riley Pathfinder replaced the RMF. This is the last car built with the Riley Big Four engine, and is thus considered to be the last "real" Riley by purists. It continued in production until 1957.

Wikimedia Commons has media related to Riley 2½ RMF saloon.

The Big Four engine is a four cylinder 2.5 litre engine rated at 16.07 h.p. under the British RAC formula. It was designed in a matter of months, under difficult financial conditions, and announced in the summer of 1937. It followed existing Riley practice, similar to their 1.5 litre engine, but with each cylinder completely surrounded by a water jacket. The fully counter-weighted and balanced crankshaft ran in three main bearings. Pre-war power output was at first 80 bhp (60 kW), then raised to 85 bhp (63 kW).^[15] In its final Riley Pathfinder form, it developed 110 bhp (82 kW), and was produced until the end of Riley Pathfinder production in February 1957.^[16]

• Ramsey, John (1984). The Swapmeet and Toyfair Catalogue of British Diecast Model Toys. Swapmeet Toys and Models Ltd. p. 29. ISBN 978-0950931906.
• Sedgwick, Michael; Gillies, Mark (1989). A-Z of Cars 1945–1970. Motorbooks International. ISBN 1-870979-39-7.
• Taylor, James (1989). Riley RM-Series. Motor Racing Publications. ISBN 978-0947981365.
• Williams, John Price (2005). Riley: The Legendary RMs. Crowood Press. ISBN 978-1861267610.