1955 Bristol 405

The Bristol Automobiles production division was a branch of the Bristol Airplane Company and launched in 1946. The company's background and skills in aeronautics would become evident in its automotive products, benefitting from wind-cheating designs that were refined in the wind tunnel by the aircraft manufacturer. The front of the Model 405 was inspired by the descendant of the 'Beaufigher,' a combat aircraft built by Bristol during World War II. The interior was luxurious, with all of the instrumentation positioned behind the steering wheel, another detail borrowed from aviation. The mechanical components were sourced from the BMW 328 but upgraded by Bristol engineers.

The 405 holds the distinction of being the only four-door car ever produced by Bristol.

The Bristol 401 and 402 were the first of the eventual five series of Bristol vehicles powered by the BMW-derived pushrod straight-six engine. The 401 saloon was introduced in 1948 and the 402 cabriolet arrived a year later. Both were developed from the Bristol 400, which remained in production alongside the 401 and 402 until 1950.

The Bristol 401 and 402 introduced modern and unique styling inspired by the Milanese designer Carrozzeria Touring. At the front, the headlights were positioned near the center of the body on either side of the narrow grille. With deep curves, flowing lines, and non-exposed door handles, the drag coefficient was less than Cd 0.36. Beneath the bonnet was the same 2-liter inline six-cylinder petrol engine that powered the 400, albeit with improved Solex carburetors. It had an improved version of the BMW M328 hemi-head engine with an unusual configuration of two separate pushrods to operate the exhaust valves.

The wheelbase measured 114 inches, the length was 191.5 inches, the width was 67 inches, and it stood 60 inches tall. The suspension was independent at the front with transverse leaf springs and wishbones, while the rear had a rigid axle with torsion bars. The 11-inch Lockheed hydraulic drum brakes at all four corners provided the stopping power.

The Bristol 403, produced from 1953 to 1955, wore much the same styling as the 401. Mechanical improvements included larger main bearings and larger valves applied to the 1971cc six-cylinder engine, boosting output to 100 hp (up from 85 bhp). Zero-to-sixty miles per hour now took 13.4 seconds, a considerable improvement over the 401's time of 16.4 seconds.

The suspension and brakes were improved to cope with the increase in power, with the former gaining anti-rolls at the front and the latter with 'Alfin' (aluminum finned) drums. Initially, the Alfin drums were placed at all four corners, but later examples were restricted to the front wheels.

The Bristol 404 was a two-door coupe produced from 1953 to 1958, and the 405 was a four-door saloon or two-door drophead coupe built from 1955 to 1958. Of the 308 examples of the 405 built, 265 examples were four-door saloons. The 404 rested on an eight-foot wheelbase platform, while the 405 was larger, measuring 9 feet 6 inches. The 405 used the standard chassis of the previous Bristols.

The convertible coachwork of the 405 (known as the 405D of which 43 were built) was created by Abbotts of Farnham using aluminum panels over the steel and ash frame. Most examples received the 100C version of the 2 litre six-cylinder engine, a higher specification unit that produced 125 bhp (compared to the 105 bhp of the standard 100B 405 engine). Both the 404 and 405 had higher compression ratios than predecessor Bristol vehicles, made possible due to the market having higher octane fuels, replacing the wartime low-octane 'pool petrol.' Most examples were fitted with the 1,971cc overhead valve inline-6, but a few of the later 405s were given the higher torque 2,216cc inline-6.

The 404 and 405 could be ordered with optional front disc brakes, and nearly all of the 405 drophead coupes received this feature. The steering was via a rack and pinion setup, and the improved gearbox received a much shorter gear lever.

Styling improvements bestowed upon the 404 and 405 included a radiator grille that resembled an aero engine. The 405 introduced sizable lockers in the front wings accessed externally by gullwing doors. One side held the battery and fuse panel, while the other side was used to store the jack and spare wheel.

Bristol 405 Specification
Most of the Bristol 405 models were powered by a 1,971cc overhead valve inline six-cylinder engine with three Solex Downdraft carburetors. They had a four-speed manual transmission with overdrive, an independent front suspension with transverse springs, and the back suspended by torsion bars.

by Daniel Vaughan | Nov 2023