SPECIALISTS OWNERS’ CLUB
The dynamo was separated from the magneto by now and was fitted to the front of the engine. A 1947 Speed Twin had a top speed of 84mph and would do between 58-94mpg. In 1948 the instrument panel in the petrol tank, one of the most prominent pre-war throwbacks, was deleted and instead a small rack could be fitted on to the tank, which was a popular addition, except among those who were concerned about the impact on a gentleman’s undercarriage under heavy braking.
In 1948 Triumph entered the ISDT with a new light 500 twin and as a matter of expediency used some of the parts from the leftover alloy barrelled engines as used on the now war surplus generator. There was a twin carb Grand Prix racer which used the engine too, and around 150 were made with the square barrel used on the generator. The off-roader that won the ISDT and the International Vase for the UK spawned a production version, the TR5 Trophy.
The TR5 got a new frame and that, too, was another example of military/ civilian expediency. The rigid frame was almost identical to that used on Triumph’s TRW military side valve twin, a motorcycle designed for rough off-road treatment.
Using the TRW frame as a base made the TR5 shorter than the T100 Tiger, with a more steeply angled bottom rail to the rear wheel.
The TRW frame had a short front downtube, with twin plates bolted to it extending down to the bottom cradle. The TR5 used a similar design, but with a large round hole in the plates to accommodate a dynamo at the front of the engine. Bigger wheels also helped off-road, these being 20 or 21 inches on the front and 19 at the rear.
The TRW donated some other cycle parts, but the tank and other bits of trim were unique to the TR5. Mudguards were trimmed back to stop the wheels becoming clogged with mud, and a high level 2-1 Siamese exhaust system ran down the left-hand side to reduce weight and improve ground clearance.
The Trophy had the bottom end from the sportier Tiger 100 fitted with milder cams and lower compression pistons. There was a progressive throttle that opened the carb up more slowly at lower speeds to make the TR5 easier to handle as a trials bike. The shorter frame on the first bikes made it less of a handful off-road too. The stock of leftover generator cylinder blocks soon ran out and from 1951 the engine was updated with new die cast alloy barrels with finer-pitch finning and a rounded profile and revised alloy heads. These were shared with the Tiger 100 model. The Triumph sprung hub could be pressed into service by TR5 owners, but many disliked the vagueness of the handling using the system and stuck with pure rigid rear frames.
The TR5 was a versatile machine, with a claimed 95mph top speed, and the ability to win off-road competitions. An owner really could use it as ride to work transport week in and week out, then at weekends ride it out to all manner of competitions, from scrambling to grasstrack to racing circuits, pull off the lights, bolt on a racing number and compete on it.
Triumph helped out the weekend sporting users by fitting the headlight with a plug-in socket. The brakes were small, and the speedometer was mounted in the fork crown. The chrome on the tank, with painted on panels and Triumph logo, had to be replaced in 1953 because of the shortage of nickel during the Korean War, and the TR5 got a silver paint job with the thin chromed tank strip used on other Triumph models instead.
In 1955 the TR5 got a new frame, this time with rear springing. This was a logical move, as although serious competitors preferred the dependability of a rigid, big offroaders were increasingly being used for on, as well as off-road, use.
Competition teams by now were seeking out bikes that were smaller and lighter and had begun using Tiger Cubs for trial competitions.
Meanwhile Triumph, seeking those all-important US sales, boosted the TR5 by 150cc to create the TR6 Trophy, and this overshadowed the TR5 so completely that by 1958 it had vanished from the line-up as Triumph were busy replacing their pre-unit twins with their new unit construction engine.
The TR5 was one of those happy
Triumph TR5 Trophy
ENGINE: 499cc OHV parallel twin
BORE/STROKE: 63mm x 80mm
COMPRESSION RATIO: 6:1
POWER: 19bhp
TRANSMISSION: Wet multiplate clutch, four gears, chain final drive
FRAME: Steel cradle
SUSPENSION: Front, telescopic forks, rear rigid (sprung hub as an option)
BRAKES: 7in SLS drum front 7in SLS drum rear
WHEELS/TYRES: 3x20in front and 4x19in rear
WHEELBASE: 53in (1346mm)
LENGTH: 80in (2032mm)
SEAT HEIGHT: 31in (787mm)
DRY WEIGHT: 304lb (138 kg)
FUEL TANK: 2.5 gallons (11.4 litre)
OIL CAPACITY: 6 pts (3.4 litres)
accidents, a machine of quality that was ideal for wide-open spaces in the US, Canada and Australia, while at the same time capable of coping with Britain’s sticky mud and roads damaged by war and neglected due to austerity. It helped establish Triumph as the premier builder of popular sporty twins. Regulars at bike shows and autojumbles the length and breadth of the nation, Ace Classics are the go-to supplier of pre unit spares.