TRIUMPH TR4/TR5/TR6

The name Triumph has always been associated with sporting cars, from the glorious pre-war dropheads to the delightful if slightly flawed V8-powered Stag of the 1970s. The pinnacle of Triumph's car building was the long run of true sports cars bearing the initials ‘TR’... and in particular the classic TR4, TR5 and TR6.

The first TR, the TR-X of 1950, was to have been a handsomely aerodynamic, up-market two-seater, but only three prototypes were made before the idea was abandoned. The first production TR was therefore the TR2 of 1953. This simple and practical two-seater was very lively, and was the cheapest 100 mph car around in the 1950s, selling for just $2, 500 in the USA, where enthusiasts lapped it up. Compared to the ar­chaic MG TF, which was its main competitor in those days, it looked smart and modern.

The improved TR3 brought the battle for American sales right to MG's door, vying for number-one spot with the MGA. The TR3 lasted from 1955 to 1962.

However, the Standard-Triumph group was in dire financial straits by the turn of the decade. It was losing Ъ 600, 000 a month and might have died had not the British truck-maker Leyland stepped in and bought the company in 1961. It promptly fired most of the di­rectors and embarked on a ‘new era’, targeting North America with a strong export drive, which they hoped would turn the company around.

Spearheading that drive for exports was the new TR sports car, the rebodied TR4 of 1962. The smart new set of clothes was designed by the Italian coachbuilder Giovanni Michelotti. Triumph had formed a relationship with this leading Italian designer since 1958, when he had designed pretty new bodywork for the TR3A. This was the so-called Triumph Italia, built by Vignale and for sale only in Italy. However, Triumph was obviously impressed and asked Michelotti to style the TR4 and, as it transpired, every Triumph for the next ten years.

The TR4 was a foot longer than the old TR3, the 3in wider track made it look lower, while at the same time improving stability and handling. The ‘hooded’ headlamps were a distinctive feature.

With full doors and winding windows, the TR4 was also a lot more comfortable than the TR3, which had cut-away doors and simple side screens. The cockpit was certainly much more roomy and plush than the out­going model, and featured face-level ventilation. There was also a novel optional extra called a Surrey top. This was a half-hard top, where the rear section remained fixed and the central part of the roof could be lifted out and replaced by a canvas top. This in turn could be furled back for semi-open motor­ing. The system was a precursor of the Targa top, which would later be popularised by Porsche.

Underneath the attractive steel bodywork laid essentially the same chassis as the old TR3. That meant a separate chassis, rigid rear axle with leaf-spring suspension, front disc brakes and a four-speed manual gearbox (with optional overdrive). The main chassis advances for the TR4 were standard servo brakes and rack-and-pinion steering in place of the cam-and-lever type.

However, perhaps the biggest change for the driver was an expanded version of the four-cylinder engine, which could trace its origins back through the Standard Vanguard saloon to the days when it powered Ferguson tractors. In the TR4, it had grown from 1991cc to 2138cc.

The power output remained the same at 100 bhp, but the engine had a wider power band and much better torque. Compared to the old TR3, it was also faster, capable of reaching 110 mph and doing the 0-60 mph sprint test in just over ten seconds.

The smaller 2.0-litre engine remained available, however, because there was still a strong competition class for sub-2000cc engines. The TR4 proved a popular choice for rally drivers. Triumph's works team scored a string of class wins through the 1960s and fielded TR4s with success in the Alpine Rally and at Le Mans.

Leyland's renewed vigour brought the desired in­crease in production. The whole group's output went up by a third. The TR sports car scored a real hit: pro­duction trebled between 1961 and 1964, going from un­der 3, 000 units to over 9, 000. Export sales of the TR range were responsible for keeping Triumph in the black throughout the 1960s. An improved version called the TR4A arrived in 1964, whose main difference was the adoption of a su­perior coil-spring and trailing-arm independent rear suspension. This had a negative effect on overall weight (pushing it up by 100 Ib) but handling was much improved. Any performance loss due to the extra weight was countered by raising the engine's power output slightly to 104 bhp.

By this time, Triumph was also experimenting with the idea of fuel injection - the first British manufacturer to try it. It decided to use the TR as its testbed for a new fuel-injected version of the six-cylinder engine from the Triumph 2000 saloon. The capacity was raised to 2.5 litres and, despite the larger capacity and extra pair of cylinders; the new engine was a comfortable fit in the TR engine bay -and no heavier than the old ‘four’.

Lucas supplied the injection technology for what would become known as the Triumph TR5, which was launched in 1967. Early examples were rather temp­eramental but the injection system was quickly sorted out and customers were soon enjoying the pleasures 150 bhp could bring - 120 mph and 0-60 mph in 8.8 seconds. Other mechanical improvements included bigger brakes and stiffer suspension. Since the TR4 had never been noted for the comfort of its ride, the TR5 felt fairly harsh on rough ground.

Fuel injection was discounted in America, where advancing emissions regulations had forced Triumph to fit plain Stromberg carburettors, and as a result power plummeted right back down to 104 bhp. The Ameri­can market version was known as the TR250 and could be identified by its contrasting stripes over the car's nose.

The TR5 and TR250 were short-lived (lasting only one year) but they were good sellers, and three-quarters of the 11, 431-strong production total went to the USA.

The model was replaced in 1968 by the TR6, basi­cally a TR5 restyled front and rear by Karmann of Ger­many. The seats were new and buyers got a front anti-roll bar, but underneath it was basically the same TR story as ever, now beginning to look rather antique. The power units were the same, too, with the 104 bhp version remaining in the USA (although European cus­tomers were subjected in 1972 to a drop in power from 150 bhp to 124 bhp).

The TR6 died as late as 1976, the last of a long string of ^‘real’ Triumph sports cars in the traditional sense. By then the TR7 had already arrived, a radi­cally different Triumph sports car. The TRs may not always have been very refined but their muscular character and handsome shape continues to endear them to tens of thousands of owners today. Apart from the MGB, the Triumph TR series is probably the most popular classic sports car in the world, as burgeoning Triumph owners’ clubs can testify.