Editing Triumph Spitfire (section)

==Spitfire 4 or Mark I (1962–1964)==
{{Infobox automobile |sp=uk
| name = Triumph Spitfire 4 (Mark I)
| production = 1962–1964<br />45,753 made
| engine = {{cvt|1147|cc|cuin|1}} [[Overhead valve engine|OHV]] [[Standard SC engine]] [[Straight-four engine|I4]]
| transmission = 4-speed [[Manual transmission|manual]] with optional [[overdrive (mechanics)|overdrive]] on top and third from 1963 onwards
| weight = {{cvt|1568|lb|kg}} (unladen U.K.-spec)
| image = 1963 Triumph Spitfire - fvl (12913101975).jpg
}}
The production design changed little from the prototype: the full-width rear bumper was replaced by two part-bumpers curving around each corner, with overriders. Mechanicals derived from the Herald saloon/sedan, with the notable addition of front disc brakes. Bodywork was bolted to the much-modified Herald chassis, the outer rails and the rear outriggers having been removed; with structural outer sills to stiffen the overall design.
[[File:Triumph Spitfire4 - Morges 2021 - Rear three-quarters.jpg|left|thumb|Rear view]]
The engine was an {{cvt|1147|cc|cuin|1}} [[Inline-four engine|four-cylinder]] with a pushrod [[Overhead valve|OHV]] [[cylinder head]] and two valves per cylinder, using twin [[SU carburettor]]s. The Herald's [[rack and pinion]] steering and [[coil-and-wishbone]] front suspension carried over, having derived from systems used by the former [[Alford & Alder]] company that had been acquired by Standard-Triumph in 1959.

Rear suspension was by a single transverse-leaf [[swing axle]],{{sfnp|Blunsden|1962|p=16}} an arrangement, that unless ameliorated by any of several options, can allow rear tyres to undergo large [[camber thrust|camber]] changes during fast cornering, leading to [[oversteer]]&nbsp;– a [[Directional stability|dynamically unstable]] condition in which a vehicle can lose control and spin. As did many manufacturers who used a swing axle arrangement (e.g., Mercedes, Renault, Volkswagen), Triumph would later modify the rear suspension. In 1970, the rear suspension was decambered, by incorporating what Triumph called a "swing spring". One leaf was eliminated from the stack and only the bottom leaf was attached rigidly to the differential. The remaining leaves were mounted to pivot freely &mdash; thereby eliminating the worst characteristics of the original [[Swing axle|swing-axle]] design.

The Spitfire was an inexpensive small sports car and as such received rather basic trim by today's standards, including rubber mats and a large plastic steering wheel. It was nonetheless considered fairly comfortable at the time, as it had wind-down windows and exterior door locks, as well as relatively full instrumentation.{{sfnp|Blunsden|1962|p=16}} These early cars were referred to both as "Triumph Spitfire Mark Is" and "Spitfire 4s",{{sfnp|Robson|1982|p=187}} different from the later Spitfire Mark IV. The "Spitfire 4" name indicated the possibility of the appearance of a six-cylinder version.{{sfnp|Blunsden|1962|p=17}}

In UK specification the inline four produced {{cvt|63|bhp|kW|0}} at 5,750&nbsp;rpm, and {{cvt|67|lbft|Nm|0}} of torque at 3,500&nbsp;rpm. This gave a top speed of {{cvt|92|mi/h|km/h}}, and a 0 to {{cvt|60|mi/h|km/h}} acceleration in 16.4 seconds. Average fuel consumption was 31 mpg.{{sfnp|Robson|1982|p=187}}

For 1964 an [[Overdrive (mechanics)|overdrive]] became optional to the four-speed [[manual gearbox]].<ref name=Autocar197306/> Wire wheels and a hard top were also available.<ref name=Autocar197306/>
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