The Triumph TR3 is a British sports car produced between 1955 and 1962 by the Standard-Triumph Motor Company of Coventry, England. A traditional roadster, the TR3 is an evolution of the company’s earlier TR2 model, with greater power and improved braking. Updated variants, popularly but unofficially known as the “TR3A” and “TR3B”, entered production in 1957 and 1962 respectively. The TR3 was succeeded by the Michelotti-styled, mechanically similar Triumph TR4.
The rugged ‘sidescreen’ TR, so named for its employment of removable plexiglass side curtains, was a sales and motorsport success. With approximately 74,800 TR3s sold across all variants, the model was the company’s third best seller, behind the TR7 (111,500 units) and TR6 (94,500 units) models.] The Triumph was campaigned in races, hill climbs, and rallies across Europe and North America, with several outright, team, and class victories to its credit. Although the car was usually supplied as an open two-seater, an occasional rear seat and bolt-on steel hard top were available as extras.
The car is powered by the Standard wet liner inline four, a 1991 cc straight-four OHV engine initially producing 95 bhp (71 kW; 96 PS), an increase of 5 hp over the TR2 thanks to the larger SU-H6 carburettors fitted. This was later increased to 100 bhp at 5000 rpm by the addition of a “high port” cylinder head and enlarged manifold. The four-speed manual gearbox could be supplemented by an overdrive unit on the top three ratios, electrically operated and controlled by a switch on the dashboard. In 1956 the front brakes were changed from drums to discs, the TR3 thus becoming the first British series production car to be so fitted. The suspension is by double A-arms, manganese bronze trunnion, coil springs and tube shocks at the front, optional anti-roll bar, and with worm and peg steering. Unlike MGs of the same period, the steering mechanism and linkage have considerable play and friction, which increase with wear.
The rear is conventional leaf springs, with solid axle and lever arm dampers, except that the (box) frame rails are slung under the axle. The wheels are 15 inches in diameter and 4.5 inches wide (increased from 4 inches after the first few TR2s), with 48-spoke wire wheels optional. Wire wheels were usually painted, either body colour or argent (silver), but matt chrome and bright chrome were also available. The front disc or drum brakes and rear drums have no servo assistance.
Under most conditions the car is very responsive and forgiving, but it has some handling issues. The chassis, which is shared by the TR2, TR3, TR3A and TR4 has limited wheel travel. As a result, on very hard cornering, the inside rear wheel can lift, causing sudden over-steer due to the increased load on the outside rear tyre. This is particularly true with radial tyres, the original TR2/3/3A suspension was built with older, cross-ply tyre designs in mind. The wheel lifting is more sudden than that of other cars, because it is caused by coming to the end of the suspension travel while there is still load on the tyre, so the load on the other (outside) rear wheel is a discontinuous function of cornering load, rather than just changing slope.
The TR3 is a true roadster, designed for sunny weather but with removable rain protection. It has a convertible hood that snaps on and off and removable side curtains, allowing very low doors with padding for the driver’s arm to rest on.
Some 13,377 examples of the original “pre-facelift” TR3 were produced, of which 1,286 were sold within the UK; the rest were exported mainly to the USA. TR3 specifics
Production period – October 1955 to Summer 1957
Original price (basic model) – £950
Suspension – Front: independent by unequal-length double wishbones, coil springs and telescopic dampers. Rear: live axle, half-elliptic springs, lever arm dampers.
Brakes – First 4408 models (1955–56): 10-inch (254 mm) drums all around. Remaining 9000 (1956–57): front discs; rear drums.
Factory options and extras – Triumph offered a wide range of optional parts and accessories for both the competition-minded enthusiast and those simply wishing to personalize their vehicle. While many of these items were factory fitments, local dealers supplied some as well. Among these were: overdrive, wire wheels (48-spoke, 60-spoke available from 1959), steel hardtop kit (part No. 900711), occasional rear seat (No. 801264), push-button radio, interior heater, leather upholstery, windscreen washer (No. 553729), cast aluminium sump (No. 502126), 2138cc engine (from 1959), aluminum ‘Al-fin’ brake drums (No. 202267 or No. 301590 (9- and 10-inch respectively)), spot and fog lamps (Nos. 501703, 501702), and a continental touring kit (No. 502022, spares for travels in remote regions).