1967-1968 Triumph TR250 Review
The need for two different models was due to US exhaust emissions regulations designed to cut down air pollution, something that was becoming an increasing problem in America's car-dependent culture. As the US was such a vital market, British manufacturers had to look at ways to reduce emissions. Most involved some form of detuning, which almost inevitably resulted in a loss of power - undesirable for a sportscar! For Triumph, the 'fix' involved a bit of old technology applied to their newly developed evolution of the popular 'TR' range of sports roadsters.
First revealed in the latter half of 1967, the TR250 was significant in that it marked the first appearance of a six-cylinder engine in a TR. A six had featured in the fixed roof GT6 coupe, but up to that point in time, the TRs had all been powered by a four-cylinder engine. The 2498cc six was virtually the same as that used in the GT6 and 2000 sedan, but with the stroke increased to 95mm to give the extra capacity, and required only minor chassis modifications to fit. The same six-cylinder engine and transmission was also offered in the 'TR5', which was the version of the TR250 sold in all markets other than the USA.
The main difference between the two was the induction system. The TR5 debuted fuel injection, which was a progressive feature, but Triumph engineers soon realised there was no way they could make the new induction system emissions compliant for the US market. The solution? Triumph looked back to carb induction, something that had been a feature on all previous TRs, but the units selected for the TR250 weren't the SU carburettors of the early TRs, but Zenith-Strombergs, which had been developed in part by Triumph, and used on TR4s since 1963. The Strombergs featured an automatic vacuum spark retard and throttle opening to effect a more complete combustion, thus making them 'cleaner'. For the TR250, the Strombergs were sealed at the factory to prevent aftermarket adjustment, although how often this was adhered to is debatable. Another bonus with the Strombergs is that they were cheap to fit.
Proven in Triumph's competition cars, the Lucas-developed fuel injection meant the TR5 delivered around 150bhp. 'Detuning' the TR250 via the Stromberg carbs meant that it delivered only around 104-110bhp. This was quite a difference, and virtually the same as the four-cylinder TR4 it replaced. Where the TR250 did excel was in torque, fuel economy and power delivery. The TR4's four-cylinder had been criticised for its rough and snappy power delivery, but the TR250's inline six was much smoother, a feature the US market seemed to appreciate. In the US at least, the market for vehicles like this was evolving from the 'raw' racers of the past to those who were buying sportscars as 'lifestyle' vehicles, wanting more comfort and refinement for weekend jaunts. The demands of the carb induction meant that TR250s ran a different compression ratio, gearing and a different rear axle ratio to the TR5, while the US models also featured different tyres than the TR5. Overdrive was optional, but appears to have been fitted to many TR250s. Again, this robbed a little top speed, but made for smoother general running and improved fuel economy.
Just as emissions regulations were becoming a factor in vehicle design, so too were safety regulations. These were somewhat minor considerations on the TR250, but did include things like a padded steering wheel (which was an inch smaller in diameter than that on the TR4) and non-protruding 'safety' switches. Servo-assistance on the disc front/drum rear brakes debuted with the TR250/TR5, as did larger radial ply tyres. Seats were more plushly-trimmed, gauges repositioned for greater legibility and the addition of 'eyeball' fresh air ventilation on the TR250 reflected the move into a more comfort and luxury-oriented market. A timber-faced dash panel was standard. The convertible top featured Velcro strips to seal against drafts, a padded centre support bar, and a new form of lever and pin fixture to the windscreen that was easier and safer to operate than the clamps from previous models. While all TR250s were soft tops, there was an optional 'Surrey' removable hardtop available. This comprised a wraparound rear windscreen and soft vinyl or rigid roof panel which gave the appearance of a hardtop. These factory option tops are quite rare today.
Appearance wise, both the TR250 and TR5 looked almost identical to the TR4A they replaced. Only detail and garnish differences distinguished the TR250 from its predecessor. These included a large, offset 'TR250' badge on the bonnet, with the model name repeated on the rear quarter panels and the bootlid. The grille was also mildly redesigned. A distinctive visual feature on all TR250s was a 'racing stripe' - a thick band with two parallel thin bands - that ran across the front of the bonnet and sloped diagonally across the guards to the wheelwells. Steel wheels were standard fitment, with wheelcovers designed to mimic the look of the popular 'Rostyle' five spoke alloys, right down to fake wheel nuts! Wire wheels were a cost option, which a lot of TR250s are fitted with today. New on the TR250 wire wheels was a hex nut fastening, instead of the wing nut style that required a special tool.
The TR250 officially had only one selling year - 1968 - but was exported to the US from late 1967, with close to 2,500 units shipped before the calendar ticked over. The TR250 was only on the market for 15 months, before the TR6 arrived at the end of 1968. Despite this, over 11,000 units were produced, far more than the TR5. While the TR5 may be more desirable than the TR250, it's also a lot harder to find, and generally more expensive. The 'interchangability' between the TR5 and the TR250 makes RHD conversion easier, which has been applied to several TR250s in this country. The bonus for buyers is that most TR250s still in circulation today will likely have been restored and well looked after. While it may lack the outright grunt of the TR5, the TR250 is still quick and presents as a very smooth and enjoyable 'weekender'.
SPECIFICATIONS: 1967_8 Triumph TR250
Engine: 2.5lt OHV inline six cylinder
Bore/Stroke: 74.7mm x 95mm
Compression: 8.5:1
Power/torque: 104bhp@4500rpm / 143lb/ft@3000rpm
Fuel system: Twin Stromberg carburettors
Cooling system: Liquid
Electrics: 12 Volt
Transmision: 4-speed manual with optional overdrive
Front Suspension: Independent coil springs/shocks/wishbones
Rear Suspension: Independent coil springs/semi-trailing arms and lever arm dampers
Steering: Rack and pinion
Front brakes: 10.9" (277mm) disc
Rear brakes: 9 x 1 3/4" (230mm) drum
Wheels: 15" Fr/Rr
Tyres: 185/SR x 15 Fr/Rr
Wheelbase: 88" (2,235mm)
Length: 153.6" (3,901mm)
Width: 58" (1,473mm)
Weight: 2,268 lb (1,029kg)
0-100 kph: 10.5 seconds - approx
Top Speed: 175 kph - approx
