Triumph TR3

Triumph TR3
Overview
Manufacturer - Standard Motor Company
Production - 1955-1962
Assembly - Coventry, England / Melbourne, Australia / Liege, Belgium / Mechelen, Belgium / South Africa
Body and chassis
Class - Sports car
Layout - FR layout
Powertrain
Engine - 1,991 cc (121.5 cu in) I4 (TR3, TR3A) / 2,138 cc (130.5 cu in) I4 (TR3B)
Transmission - 4-speed manual, optional overdrive
Dimensions
Wheelbase - 88 in (2,235 mm)
Length - 151 in (3,835 mm)
Width - 56 in (1,422 mm)
Height - 50 in (1,270 mm)
Kerb weight - 955 kg (2,105 lb)
Chronology
Predecessor - Triumph TR2
Successor - Triumph TR4

The Triumph TR3 is a British sports car produced between 1955 and 1962 by the Standard 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 mechanically similar, Michelotti-styled Triumph TR4.
The rugged ‘sidescreen’ TR, so named for its use 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 in the TR range, behind the TR7 (111,500 units) and TR6 (94,500 units) models.
TR3
Although the base car is an open two-seater, an occasional rear seat and bolt-on steel hard top were available as extras.
The TR3 is powered by a 1,991 cc (121.5 cu in) Standard wet liner engine. This OHV straight-four initially produced 95 bhp (71 kW; 96 PS), an increase of 5 hp over the TR2 thanks to larger SU H6 carburettors. 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 electrically engaged overdrive, controlled by a switch on the dashboard. In 1956, the front brakes were changed from drums to discs, a first for a British series production car.
Front suspension is by double wishbones, manganese bronze trunnions, coil springs and telescopic dampers, with an optional anti-roll bar.
Steering is a worm and peg system. Unlike MGs of the same period, the steering mechanism and linkage have considerable play and friction, which increase with wear.
The rear suspension comprises leaf springs, a beam axle, and lever arm dampers. The (box) frame rails are slung under the axle. 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 matte chrome and bright chrome were also available.
Under most conditions the car is responsive and forgiving, but it has some handling issues. The chassis, which is shared by the TR2, TR3, TR3A, TR3B, and TR4, has limited wheel travel. As a result, on very hard cornering, the inside rear wheel can lift, causing sudden oversteer 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 for crossply tyres. 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. There are holes in the floor, with rubber plugs, so that the originally supplied jack might be used from inside the car, as in the Jaguar XK120. The optional heater is poor, and the shut-off valve is under the bonnet.
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 US. As of Q1 2011 there were approximately 826 licensed and 115 SORN TR3/3As registered with the DVLA.
Specifications
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.
Tyres - 5.50-15 crossply or 155HR15 Pirelli Cinturato CA67
Factory options - Triumph offered a wide range of options and accessories for both the competition-minded owner and those simply wishing to personalise 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), aluminium ‘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).
Performance
British auto magazine The Motor tested a hardtop TR3 with overdrive in 1956. The car returned a top speed of 105.3 mph (169.5 km/h) and could accelerate from 0-60 mph (97 km/h) in 10.8 seconds. A fuel consumption of 27.1 miles per imperial gallon (10.4 L/100 km; 22.6 mpg‑US) was recorded. The test car cost £1,103 including taxes.
Other figures recorded included:
Speed - Time
0-30 mph (48 km/h) - 3.6 s
0-50 mph (80 km/h) - 7.5 s
0-60 mph (97 km/h) - 10.8 s
0-90 mph (140 km/h) - 28.8 s
Distance - Time
Standing 1⁄4 mile - 18.1 s

1957 Triumph TR3

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