ERA
R4D

Why it matters

The R4 chassis is credited with 26 victories, making it the single most successful ERA chassis ever built. The Ultimatecarpage text is headed R4D but refers to the car as R4B in its body; either way it is the Raymond Mays car converted to C-type and then D-type specification.

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

The car was driven mainly by Raymond Mays, who entered it in major Grand Prix and local British road races and hill climbs, especially Shelsley Walsh. Two years into its career a 2-litre engine and a revised box-section chassis with independent front suspension brought it to C-type specification, and a year later it became a D-type with a drilled lightweight chassis. It raced into the 1950s with drivers such as Reg Parnell and remains a regular competitor in historic Grand Prix races.

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.

D-type specification, as described by the source, means a 2-litre engine, a drilled lightweight chassis and independent front suspension, with the car in that state today although many worn parts were replaced.

Sources

Each number links to the exact facts it supports.

1. 1
   ERA Club – car information / chassis histories Level B

   • 1 individual car: chassis R4, which became R4D in 1938 with a new chassis frame (identity confirmed)

   Accessed 2026-11-12
2. 2
   ERA D-Type chassis R4D Level B Ultimatecarpage.com · 2006-01-04

   • Of the 17 ERAs constructed
   • A 2 litre engine
   • independent front suspension

   Accessed 2026-11-12