For many years the USA was the most important market for British sports cars, and at the time the TR7 was planned it was thought, mistakenly as it transpired, that the increasingly safety conscious US authorities would ban the import and production of open cars.
Not surprisingly Triumph played safe in deciding on an enclosed model, and once that decision was taken it was felt easy and desirable to adopt the wedge shape styling then coming into vogue. Apart from the slightly controversial, and not universally popular, styling the car was mechanically quite simple.
The front-mounted overhead cam engine was basically similar to that of the Dolomite Sprint, being the same capacity but without the sixteen valve head. Whereas the TR5 and TR6
featured double wishbone front, and independent rear, suspension, the TR7 used the MacPherson strut front suspension
usually found in sedans (with the notable exception of Fiat's X1/9
sports car) and reverts to a simpler live rear axle layout.
The axle was so well located, however, by a four link trailing and semi-trailing system, that it is no drawback. The well balanced handling is a considerable improvement over that of the older TRs, and inspired great confidence in the car. Performance from the 2-litre engine was good, but the TR7 was in fact slower overall and in acceleration than its stable-mate, the Dolomite Sprint
The wedge shape had its drawbacks in that the strong, but rather wide, roof pillars which provided good roll-over protection hampered rear side vision, and the steeply sloped bonnet line makes the front of the car difficult to locate in heavy traffic and parking.
The Triumph TR7 Convertible
British Leyland's treatment of the TR7 in convertible form was refreshing, the often too rare sight of a tin-top minus the roof in the case of the TR7 working extremely well, and the absence of a 'Targa top' endowing it with a slim, elegant look. The hood too folded away in a neat manner, and was not a lengthy operation.
The TR7 Convertible retained identical mechanicals to the Coupe, the engine being a two-liter version of the eight-valve 'Dolomite' engine, or, if you like, an eight-valve edition of the 16-valve 'Dolomite Sprint' motor. The five-speed gearbox was light and easy to operate, and stemmed from the British Leyland Rover SD1 unit (also used in the Series III Jaguar and Daimler models).
Rear drive was to a live axle, and at the time was regarded by some obbservers as dated but it mads for easy production (and this in turn made the car a viable prodution option), and minimised price levels. The Convertible at 2315 Ib (1050 kg) was a little heavier than the closed TR7, but there was considerable comfort for two (and a large luggage boot) and a top speed of 109 mph (175 km/h) which, in view of the simple layout, was pretty reasonable.
Triumph TR7 Quick Specifications:
Front mounted, 45 degree slanted in-line water cooled four cylinder. 90.3 mm (3.56 in) bore x 78 mm (3.07 in) stroke - 1998cc (121.9cu in). Maximum power (DIN) 105 bhp at 5500 rpm; maximum torque (DIN) 119lb.ft. at 3500 rpm; cast iron cylinder block and light alloy head. Compression ratio 9.25:1. 5 main bearings. 2 valves per cylinder operated by single overhead camshaft and thimble tappets. 2 SU HS6 carburetors.
Single dry plate clutch and manual 4-speed gearbox. Ratios 1 st 2.646, 2nd 1.779, 3rd 1.254, 4th 1.0, reverse 3.050. Hypoid bevel final drive, ratio 3.630.
Front-independent by MacPherson struts, coil springs, lower wishbones and anti-roll bar, rear-live axle with lower trailing arms, and upper oblique torque arms, coil springs and anti-roll bar.
Rack and pinion. Turns from lock to lock 3.87.
Discs front and drums rear, dual hydraulic circuit serve assisted.
13 in x 5.5 in.
185SR x 13.
Dimensions and weight:
Wheelbase 85.04 in; track- front 55.47 in, rear-55.28 in; length 160 in; width 66.20 in; height 49.4 in; ground clearance 4.5 in; dry weight 21481b; turning circle between walls 29ft; fuel tank 14.5 gals.
2 door, 2 seat. Integral, with front sub-frame.
Maximum speed 109 mph; acceleration O-60 mph 9.1 secs. Fuel consumption approx. 26 mpg.