Triumph TR5

Triumph TR5 Triumph TR250
Overview
Manufacturer	Triumph Motor Company
Production	1967–1968
Assembly	Coventry, England
Designer	Giovanni Michelotti
Body and chassis
Class	Sports car
Body style	Roadster
Layout	Front-engine, rear-wheel-drive
Powertrain
Engine	2.5 L straight-six
Transmission	4-speed manual, optional overdrive
Dimensions
Wheelbase	2,240 mm (88 in)
Length	3,902 mm (154 in)
Width	1,470 mm (58 in)
Height	1,170 mm (46 in)
Kerb weight	1,030 kg (2,271 lb)
Chronology
Predecessor	Triumph TR4A
Successor	Triumph TR6

The Triumph TR5 was a roadster sports car built for a 13-month period between August 1967 and September 1968 by the Triumph Motor Company in Coventry, England.^[1]

Visually identical to the Michelotti styled TR4,^[2] the TR5 hid the main differences under the body. The most significant change from the TR4 was the 2.5-litre straight-6 fuel-injected engine, developing around 145 hp (145 bhp), and which was carried forward to the TR6. A carburetted version of the TR5 named Triumph TR250 was manufactured during the same period, to be sold in place of the fuel injected car on the North American market.

At the time, fuel injection (or PI petrol injection, as it was sometimes then called) was uncommon in road cars. Triumph claimed in their sales brochure that it was the "First British production sports car with petrol injection".^[3][4]

In 1968, the basic price of the TR5 in the UK was £1,260 including taxes, with wire wheels being another £38, overdrive £60 and a tonneau cover another £13.^[4]

Triumph TR250

The Triumph TR250, built during the same period for the North American market, was nearly identical to the TR5. But, because of price pressures and emission regulations the TR250 was fitted with twin Zenith-Stromberg carburettors rather than the Lucas fuel injection system. The reasons for this difference came down to price pressures of the American market, and tighter emissions regulations. The TR250's straight-six engine delivered 111 bhp (81 kW), 39 bhp less than the TR; 0–60 mph (0–97 km/h) acceleration took 10.6 seconds.^[2][5]

Triumph TR250

In 1968, the TR250 sold in North America for approximately $3,395, with wire wheels being another $118, overdrive $175 and air conditioning another $395.^[6]

Specifications

Standard equipment included front disc brakes, independent rear suspension, rack and pinion steering and a four speed gearbox. Optional extras included overdrive and wire wheels. Both the TR5 and the TR250 were available with the "Surrey Top" hard top system: a weather protection system with rigid rear section including the rear window and removable fabric section over the driver and passenger's heads.

TR5

A curious feature of the TR5/Lucas petrol injection system was the very frequent occurrence of an intermittent power failure when the fuel tank was no more than a quarter full. In order to provide fresh fuel at the distributor, free from overheating/soak, unused fuel was returned to the tank where it entered very close to the high pressure fuel pump. When the fuel level fell below critical (about 3 gallons), sloshing would cause the pump to pick up a slightly aerated mixture which was sent to the fuel distributor. Unused fuel (still aerated) then passed back to the tank and was discharged close to the pump, a proportion of it being picked up and recycled to the distributor. As this cycle was repeated, gradually the volume of air in the pumped fuel reached a level where it began to affect the running of the engine. Adding as little as one gallon to the tank seemed to cure the problem. The similarly engined contemporary saloon overcame this problem with a petrol tank specially designed for the fuel injected model. This incorporated an anti-slosh cup to ensure that the fuel outlet remained covered with fuel when the tank level was low.

Taken from the UK sales brochure.^[3]

Triumph TR250 Surrey Top

• Engine: 2498 cc, 6 cylinder, 74.7 mm bore, 95 mm stroke, 9.5:1 compression ratio
• Turning circle: 10.1 m (33.1 ft)
• Ground clearance: 152 mm (6.0 in)
• Luggage capacity:
  • Max width: 1,180 mm (46.5 in)
  • Max height: 510 mm (20.1 in)

• Capacities:

Fuel tank: 51 litres (11.22 imp gal; 13.47 US gal)

Engine sump: 4.53 litres (1.00 imp gal; 1.20 US gal)

Gearbox: 1.13 litres (0.25 imp gal; 0.30 US gal)

• Acceleration in top:

30 to 50 mph: 7 s

40 to 60 mph: 7 s

60 to 80 mph: 8 s

• Standing 0.25 miles (0.40 km) : 16.5 s
• Gear ratios:

• Available colours:^[1]

TR250

Engine: 2,498 cc, inline-six cylinder, 74.7 mm (2.9 in) bore, 95 mm (3.7 in) stroke, 8.5:1 compression ratio, 111 bhp (83 kW; 113 PS) at 4,500 rpm

Turning circle: 10.1 m (33 ft)

Capacities:

Fuel tank: 61 L (13.5 imp gal)

Engine sump: 5.4 L (9.64 imp pt)

Gearbox: 1.13 L (2 imp pt)

Performance:

0 to 60 mph (97 km/h): 10.6 seconds^[7]

0 to 100 mph (160 km/h): 39 seconds

Fuel consumption: 23.5 miles per US gallon (10.0 L/100 km; 28.2 mpg_-imp) ^[8]

Performance

The fuel-injected engine could propel the TR5 from 0–50 mph (80 km/h) in just 6.5 seconds, and on to a top speed of 125 mph (201 km/h).^[3] Road tests at the time reported slightly different performance figures:^[9]

Production

The TR5 was produced in small numbers when compared with the later TR6, with just 2,947 units produced; the first car was assembled on 29 August 1967 and the last on 19 September 1968. Of these, 1,161 were destined for the UK market,^[10] the remainder being LHD TR5s and going to France, Belgium and Germany amongst others. In a similar period 8,484 TR250s were built for the U.S market.^[1] In the first quarter of 2011 there were approximately 410 licensed and 74 SORN TR5s registered with the DVLA.^[11][12]

The TR250 was built in 8,480^[13] units, all of which were for the American market. Approximately 600 remain worldwide today, and many can now be found outside the United States, primarily in Europe.

Gallery

• Triumph TR5
• 

  1968 TR5 front quarter view

• 

  1968 TR5 interior

• 

  1968 TR5 engine bay

• 

  1968 TR5 rear quarter view

• 

  TR5 with hardtop fitted

References

Wikimedia Commons has media related to Triumph TR5.