ERA
R-type voiturette (A/B/C/D)

Why it matters

ERA's R-type cars made Britain competitive in 1930s voiturette racing, and only 17 were built in Bourne, Lincolnshire. All but one survive, and cars like Prince Bira's Romulus and Remus remain central to historic racing.

How rare is it?

Six separate kinds of rarity – never combined into one number.

Each kind of rarity is rated separately and never combined.

Production

Every figure says what it counts.

Independent counts (e.g. engine and colour) are never combined into a calculated figure. Surviving examples are never presented as original production.

History

Peter Berthon, Raymond Mays and Humphrey Cook founded English Racing Automobiles in 1933 to contest second-tier voiturette racing rather than take on the big Grand Prix teams. Using engines based on the Riley six, the first car was unveiled at Brooklands in May 1934, and R3A gave ERA its first international win at the Nürburgring in 1935. Bira, Richard Seaman and Tony Rolt were among the early drivers, and Mays set the final pre-war Shelsley Walsh record in R4D in 1939. The only car lost is R3B, destroyed in Marcel Lehoux's fatal crash at Deauville in 1936.

Technical specifications

Engine

Transmission & drivetrain

Chassis, body & dimensions

Performance

“Not yet verified” means no source has been checked for that value yet. Nothing is estimated to fill a gap.

Identification guide

How to tell an original from a replica or later conversion.

ERA cars are identified by the chassis code: R1A to R4A are the four works A-types of 1934-35, and the 13 customer B-types run R1B to R14B (R13 was not used). C- and D-types were rebuilds of existing chassis, so a single chassis can carry several letters (for example R4B became C-type then D-type, and R12B became R12C and back). The Riley-based six has camshafts on both sides operating pushrod valves, with a Roots-type or Zoller supercharger, and the gearbox is a Wilson pre-selector.

Sources

Each number links to the exact facts it supports.

1. 1
   ERA D-Type chassis R4D Level B Ultimatecarpage.com · 2006-01-04

   • Of the 17 ERAs constructed

   Accessed 2026-11-12
2. 2
   Autosport – ERA at 90: pre-war racers Level B

   • 17 cars built; all bar one survive

   Accessed 2026-11-11
3. 3
   The pre-war racers of a landmark English constructor celebrating 90 years Level B Paul Lawrence · Autosport · 2024-11-20

   • all but one survive; R3B destroyed at Deauville
   • engines based on the six-cylinder Riley unit

   Accessed 2026-11-11
4. 4
   ERA R2B "Romulus" Level B Supercars.net

   • Capacity: 1,488 cc
   • Bore X Stroke: 57.5 mm / 90.8 mm
   • Power: 166 bhp / 124 KW @ 6,500 rpm
   • 166 bhp @ 6,500 rpm
   • Wilson pre-selector gearbox
   • ladder-frame chassis
   • Wheelbase: 2,438 mm (96 in)
   • Front: 1,333 mm (52.5 in)
   • Rear: 1,219 mm (48 in)
   • Weight: 914 kilo / 2,015 lbs

   Accessed 2026-11-12
5. 5
   ERA R11B 'Humphrey' - Specifications Level B Ultimatecarpage.com · 2007-10-01

   • live axle, semi-elliptic leaf springs, Hartford friction dampers
   • live axle, semi-elliptic springs, Hartford friction dampers
   • Lockheed drums, all-round
   • Burmann steering box

   Accessed 2026-11-12