The Sweet Spot
Despite the strong sales enjoyed by the TR3, plans for its successor had begun in 1957 with the replacement scheduled to debut in 1959. Italian designer Giovanni Michelotti was commissioned to work on the new design but his first attempt – though striking – was far too fashionable to have aged well and the second effort – codenamed Zest – was better received but soon abandoned due to an effort to bring the proposed Herald to market as quickly as possible. The third try occurred during the winter of 1958-1959 – codenamed Zoom – and this prototype featured a longer wheelbase and wider track that would more closely approximate the eventual TR4. By 1960, it was decided to combine the best elements of the Zest and Zoom prototypes on to a chassis that was essentially identical to the chassis used on the TR3 but with modifications that resulted in a 4-inch increase in width. The engine was to be the 2138-cc four-cylinder (which had been optional on later 3As) attached to an improved all-synchromesh gearbox and the steering changed from cam-and-peg to rack-and-pinion. As such, the new TR4 was very much the same under the skin as the TR3, but the new body styling was certainly an improvement for the better. Unlike the TR3 – with its blunt face and cut-down doors – the TR4 had a full-length grill with prominent curves featured throughout the large hood, roll-up windows and vestigial tailfins that incorporated vertical taillights. The look was a significant advancement over the stark functionality pioneered by the TR2 and the Italianate features of the TR4 would age well even as it evolved into the TR250 with only minimal decorative embellishments.
The wider track accommodated an all-new interior that offered room enough to allow separation between the shoulders of driver and passenger while also providing for an occasional rear seat that could accommodate an adult sitting sideways or two small children in moderate comfort. The full-width dashboard contained the same instruments as the TR3A but with innovative face-level vents located at either end that could direct fresh air into the cabin through an intake mounted just in front of the windshield. The interior panels, dashcap and wheel arches were nicely trimmed in vinyl with contrasting piping while loop carpeting covered the floor surfaces and transmission tunnel. Another innovative feature was the optional Surrey top that featured a fixed backlight and a removable center section that allowed for what would later be known – thanks to Porsche – as Targa-style motoring.
When the TR4 reached scale production at the end of 1961, its primary rivals – the MGA and Austin-Healey 3000 Mk I – still made do with side-curtains and –compared to the Triumph – primitive accommodations such that the new TR was greeted with strong sales demand upon arrival. The initial response from the press was positive but for complaints that the rear suspension was dated in comparison to the rest of the car and that the underslung rear axle carried over from the TR3A was the only significant blemish on an otherwise impressive car. Triumph had built its raison d’être on performance and although the top speed was not much improved from before despite the larger engine, the reservoir of available torque had been supplemented by almost 10-percent which allowed better acceleration and more grunt in lower gears.
The stability of the car was improved greatly with the increased track and the rack and pinion steering was vastly better than the venerable cam-and-peg arrangement from the earlier cars. The dampener settings were lightened in comparison to the TR3A and the TR4 managed to combine ride comfort with good handling ability without ever feeling overly compliant in the manner of the Sunbeam Alpine. Road & Track summarized the virtues of the TR4 nicely when it wrote, “the ride is firm, the steering is positive with a considerable amount of feedback when cornering hard, the brakes are excellent and the car is a lot of fun to drive.” Likewise, The Motor praised its value, finding that the TR4 offered “more performance per pound than any other production car.”
In keeping with established Triumph tradition to minimize improvements within a model run, the running changes to the TR4 were few, but late TR4s were installed with more powerful brakes, more comfortable seats and more luxury in the form of a polished walnut dash that replaced the earlier painted trim. By this time, Triumph was beginning to feel the weight of pressure levied against it by the motoring press which management feared would ultimately impact consumer sales. Inevitably, the focus was on the rear suspension with Car & Driver complaining – “one cannot help wondering how a long-standing fault of the TR3 was permitted to live on in the TR4” – while Road & Track agreed, stating – “the rear suspension is our major point of criticism, and we felt that the whole car would be greatly improved if the rear end was updated in the light of current sports car racing developments.” With potential customers reading these reviews, Triumph was forced to act and it did so with an improved TR4A.
Triumph was no stranger to the independent rear suspension, the Herald and Spitfire both used the system –crude though it was – but adapting it to the larger TR was problematic since it would require a new rear chassis section to attach the components and provide them with the necessary clearance to move. Unlike the simpler, more economical swing-axle arrangement used in the Herald and Spitfire – which itself was subject to scorn – Triumph wisely chose to adopt the more sophisticated semi-trailing arm IRS which eliminated the tendency of the smaller cars to change camber radically – and with potential danger – when the rear end unloaded in a corner.
Externally, there was little to differentiate the TR4A – introduced in 1965 – except for a new grille and chrome housings for the turn signals and sidelights mounted forward on the fenders from which trim strips extended aft to the doors. The convertible top was greatly improved too – eliminating the erect-a-set unit from the TR4 – and the handbrake was repositioned atop the tunnel from its position adjacent to the passenger’s leg while the seats featured new padding and greater rake that made them more comfortable. The engine received an increase of 5 hp due to mild revisions to the camshaft, exhaust system and inlet manifold, but the additional weight offset any performance gains. The new modifications were well received by the press, with Road & Track remarking: “the effect of the independent rear suspension is almost all good … The change in ride due to the new suspension is also little short of remarkable … The TR4 has always been capable of exhilarating performance … Now, with the IRS and the new top, the TR4A offers Triumph drivers unprecedented amounts of handling, comfort and convenience as well.”
While the new IRS answered the criticism over the antiquated live rear axle – which was still available as an option for those unwilling to pay for the independent rear end – there was renewed complaint over the fact that the car was still little faster than the TR2. Fortunately for Triumph, the TR2 had been faster than the competition so that as they improved the TR4A still held an advantage over the MGA and Sunbeam Alpine and was only marginally slower than the Healey 3000. Competition success, which had done much to enhance the reputation of the TR3, continued with the TR4 and TR4A with Team Prizes in the RAC, Tulip and Shell 4000 Rallies while Kas Kastner prepared cars won the Manufacturer’s Cup and took class wins at the 12 Hours of Sebring in both 1963 and 1966, while finishing ahead of much more exotic machinery through the blend of strong performance with bullet-proof reliability. In SCCA racing, Triumph owned D Production with the TR4 and TR4A – as well as G and F Production with the Spitfire and TR3 – with Kastner’s factory cars and privateers like Bob Tullius with Group 44 running down their competitors convincingly and consistently.
As the end of the decade approached, however, it was clear that the time had come to finally address the performance issues with introduction of a new engine that could offer not only greater horsepower, but also smoother operation than the relatively rough and noisy 4-cylinder could provide. The answer would lie with the 1998-cc inline 6-cylinder engine from the Triumph sedan, which was stroked to 2498-cc for use in the TR4A’s replacement. Management had determined that the new powerplant would have to make 150 hp to provide the desired top speed of 120 mph and sub-nine second times from 0-60 mph, but the only practical means of doing so would require installation of the new Lucas PI fuel-injection system that would make its debut in the TR5. So equipped, the TR5 became the first mass-produced injected British car and was the most affordable 120-mph vehicle in the country as well. With the exception of the new engine, the only external differences were a slightly revised grill with painted slats and new marker lights and chrome trim. Inside, a matte finish replaced the polished surface on the walnut dash while new seats debuted that were the most comfortable yet seen in a TR. Alas, despite the impressive performance that the fuel-injection made possible, restrictive emissions rules in the United States made sale of the TR5 impossible because the primitive nature of the Lucas system could not meet the Federal standards. What this meant was that while the UK and continental Europe would enjoy the fastest TR ever built, the United States would get the TR250, which featured the same six-cylinder engine fed through dual tamper-proof Zenith-Stromberg carburetors that forced use of mild cam timing – compared to the TR5 – that resulted in only 104 hp at 4500 rpm – the same output as the 4-cylinder engine in the TR4A – but increased torque to the tune of 143 ft/lbs at 3000 rpm to allow for only slightly better acceleration and top speed. While response to the TR5 was enthusiastic – “without doubt the best Triumph yet” declared Autosport – in the United States, enthusiasm for the new model was decidedly muted, with Car & Driver musing, “to pay an extra $500 for a nearly identical but slower car doesn’t make much sense.” To be fair, the TR250 was much smoother and quieter than the TR4A and Road & Track found that the new engine “could hardly run more sweetly” and changed the essence of the TR from rough and tumble to relaxed and smooth.
For all the negativity that the TR250 engendered during its brief production run – only 14 months – it is appreciated now as having combined the best elements of the TR4 with the performance potential offered by the TR6 – modern advancements and technological know-how make it possible for current owners to replicate the 150-hp TR5 with the existing carbureted setup – and like other interim models – think MG TF and 100 BN2 – it is much in demand and may, in fact, be the most desirable postwar TR in America.
The lines of the TR4A have improved with time and the Michelotti design has an elegance that is lacking in both the TR3 and TR6 and despite having a wheelbase that is 3-inches shorter than the MGB with slightly more overall length, the TR4A appears to be the more substantial car. The muted tailfins, higher fender lines and larger 15-inch wheels add to that impression, although both cars are comparable in overall height. The interior of the TR4A is more luxurious than any offered by its competitors with its polished walnut dash, leather seats and high quality carpeting. The seats are comfortable and the travel adjusted such that any sized driver can be easily accommodated within, while the three-spoke steering wheel is both attractive to look at and well positioned for use. It would be hard to improve upon the basic instrumentation package that was largely carried over from the TR2. The face-level vents are a nice touch along with the generously sized lockable glove box that is situated before the passenger. The occasional rear seat provides a flat surface upon which soft luggage can be placed since it is no longer legal to place unbelted passengers in the diminutive space.
The engine starts with a turn of the key and it springs to idle with a growl that is typical of the big four-cylinder in either 2 or 2.2-liter configuration. The pedal box is large enough that the dimmer switch – located on the floor adjacent to the driver’s kick panel – can be used as a dead pedal provided the driver is careful not to engage the switch with a heavy foot. The accelerator and brake pedal are closely located to allow for easy heel-and-toe operation and the clutch effort required for engagement is light enough to use the car in heavy traffic without much complaint. The gearbox – an all-synchromesh unit – is a delight to use although it is best used slowly – with a slight pause in the neutral position – to provide the smoothest shifts. The lever itself is short and well placed as it falls easily to hand from the steering wheel. Steering effort is very light and the slightest turns will result in a change of direction so it is best to let the car self-steer – with only a light hand on the wheel – down the freeway or long stretches of straight roads.
The exhaust note is loud and powerful although unobtrusive at moderate speeds. Acceleration – rather than outright speed – is the talent shared by all four-cylinder Triumphs and the TR4A is no exception. This trait is accompanied by an inherent roughness and the valvetrain is noisier than in any contemporary MG, but none of that detracts from enjoyment of the car. The engine will pull strongly up to the redline and has the ability to cruise all day at 80 mph without fear of damaging any internal components given its stout construction. Mileage is good – 25 mph – though not at the levels of the TR2-TR3 and the tank has sufficient capacity to allow for 250+ mile range.
The TR4A we drove was a live-axle variant so the ride is firmer than one would encounter in an IRS car but it manages to provide a comfortable ride nonetheless. With about one-third of TR4As so equipped, there are many owners that prefer the simplicity and firmer ride that the solid axle offers over the relatively complex IRS setup and competition drivers overwhelmingly favor its use to the independently suspended rear end. On all but the roughest road surfaces it is tough to distinguish between the two suspensions, though there is a greater tendency for wheel hop with the live axle and more pronounced squat during hard acceleration with IRS.
Mention should also be made of engine accessibility in the TR4A compared to the Big Healey and MGB since the large hood of the Triumph allows better access than anything short of an E-Type or Spitfire. Use of an engine-mounted AC mechanical fuel pump also offers greater reliability and access than the electric SU pump – located beneath the car in the Healeys – used in most other British sports cars, consistent with Triumph’s reputation for simplicity and reliability. In terms of performance, reliability and durability, the TR4A has few peers and the luggage capacity afforded by the large trunk and rear seat area is ideal for extended trips. Furthermore, the convenience of the Surry top is unique in providing open motoring with less wind and greater security when parked. All things considered, the TR4-TR250s are the most underrated of the Big Triumphs lacking the traditional look of the TR2-TR3 and the more modern feel of the TR6. For those enthusiasts, however, desiring a fast, attractive and practical classic capable of eating up hundreds of miles per day there is no better alternative than the Goldilocks of the TR family.