The Brstol 405 range simultaneously represented progression and retrogression from its predecessor. The body was the first Bristol not to resemble the pre-war BMW 328, and the 405 was also the first Bristol to be offered as a four-door saloon, but Superleggera construction was replaced by a partially wooden body frame. As with the 403, the engine was a 2-litre I-6 OHV unit, with rack-and-pinion steering. The suspension was independent upper wishbones and transverse leaf spring with an anti-roll bar at the front and a live axle with longitudinal torsion bars at the rear.
Bristol debuted the 405 at the London Motor Show in October 1954. Standard fittings included overdrive, adjustable steering and door armrests and ‘one-shot’ chassis lubrication. It was also the first Bristol with flashing indicators and an opening boot lid, while other features included the soon to be familiar ‘seven dial’ dashboard and a spare wheel storage compartment in the nearside front wing. Optional extras included front disc brakes. The top speed was 110mph, and the price was a £3,188 12s 1d. The large glass area earned the 405 the nickname of ‘The Flying Greenhouse’ and one interesting detail was that the rear doors were bigger than those at the front.
Choices of coachwork were the saloon and a 405D drophead coupe made to order by Abbotts of Farnham. Only 51 405 dropheads were built in contrast to 294 four-doors. Bristol 405 production ceased in 1958, following the introduction of the 406 in the previous year.
Power was from the Bristol 1,971cc triple Solex carburettor engine in 100B2 guise, and the transmission was a 4-speed manual unit with a Laycock de Normanville overdrive, a freewheel on first gear and synchromesh on the top three ratios.
For the motorist who craved genuinely exclusive transport that blended the abilities of a sports car with coachbuilt fittings, the 405 was the ideal choice. It is one of those British luxury saloons of the 1950s upon which automatic transmission would be mostly wasted, as it demands to be piloted with enthusiasm.
As the 405’s construction is a steel chassis with wood and aluminium, it should be very carefully checked for any deterioration of the timber’s condition in addition to all points where the two different metals meet. Ahead of the A-pillar the 405 and the 404 (q.v.) are the same, but many of the former's parts are unique to that model.
The Bristol 405 was a lasting reminder of how the company created its own traditions rather than slavishly following those of other manufacturers. Its aerodynamic body with its idiosyncratic lines denote a car that requires to be appreciated entirely on its own term.
The 405’s competitors included the Jaguar Mk VIIM and Mk VIII, the Alvis ‘Grey Lady’ and the Lagonda 3-Litre.