ABOVE: 1956 Triumph TR6 Trophy w/2-into-1 “siamesed” high exhaust running along the left side.
TR6 BY THE NUMBERS
1956 Engine/Frame numbers: 70199 to 82797
Production Dates: August 8, 1955 to July 27, 1956
1956 TRIUMPH TR6 – THE NEW KID IN TOWN
Triumph Motorcycles were on a roll in the 1950’s, with one hit after another. Of course the Triumph Speed Twin started the ball rolling, soon followed up by the hotrod version, the Tiger T100. Before long even this wasn’t enough and the venerable Mr. Edward Turner saw fit to enlarge his 500 twin to a 650 with the 1950 Triumph 6T Thunderbird. This too was soon eclipsed by a hotrod version, the Tiger T110.
NEW DELTA HEAD
This brings us to 1956 and the introduction by Triumph of an all new alloy cylinder head, dubbed the “Delta Head” because of its distinctive shape. The totally-redesigned head solved the overheating problems of the cast iron heads being used up to that point, and eliminated the external oil pipes by routing returning oil down through the pushrod tubes instead.
A NEW DUAL-PURPOSE BIKE
With the new cylinder head came an all new motorcycle, indeed an all new type of motorcycle, the 1956 Triumph TR6 Trophy. It was a dual-purpose bike, street legal but offroad-capable with knobby tires, minimal fenders (mudguards) & high pipes. The TR6 was clearly intended for the wide open spaces of America and the burgeoning off-road & desert racing market in the US (although it was also available in the UK and other export markets).
The 1956 Triumph TR6 shared much with its siblings, the 6T Triumph Thunderbird and the Triumph Tiger T110. The frame and running gear (cycle gear) carried over with the obvious exceptions of the headlight, fenders and pipes. The basic 650cc Tiger T110 engine was used, fitted with the new Delta Head, along with E3325 high-performance cams and an 8.5:1 compression ratio (later dropped to 8:1 in the interest of durability). Was it fast? One of the fastest motorcycles you could buy in 1956. It was the stuff of legend. Remember, the iconic Triumph Bonneville wasn’t due out for another 3 years.
A DIRT BIKE IN STREET CLOTHES
One interesting feature came with the elimination of the Tiger and T-Bird twins’ clunky headlight nacelle. The 1956 Triumph TR6 came with a sleek, tidy removable headlight with detachable wiring & even a detachable dynamo. The 1956 Triumph TR6 shared much with its smaller brother, the 500cc TR5. These included the primary chaincase, detachable dyno, oil tank, and slim dual seat. The 3-gallon fuel tank and siamesed 2-into-1 side exhaust running high along the left side (two side pipes, one on each side, became available late in the model year) completed the off-road package. Was it effective as a dirt bike? Well, at the prestigious 1957 Big Bear Run Enduro in California, TR6 Trophies took no less than the first 12 places overall!! The TR6 legend was off & running.
1956 Triumph TR6 SPECIFICATIONS
Bore & Stroke
Final drive sprockets
Air-cooled OHV vertical twin, non-unit
649cc / 40.0 ci
71mm X 82mm / 2.79″ X 3.23″
8.5:1 (US & export); 7.0:1 (UK)
42 bhp @ 6500 rpm
1/2″ X .335″ X 5/16″ chain, 70 links
21T X 43T
4-speed constant mesh, right foot shift
5/8″ X .400″ X 3/8″ chain, 101 links
18T X 43T
Brazed lug, rigid
Telescopic fork, hydraulic damping
Swing arm, 2 Girling dampers
7″ SLS drum
7″ SLS drum
3.25″ X 19″ Dunlop
4.00″ X 18″ Dunlop
55.25″ / 140 cm
30.5″ / 77 cm
5″ / 12.7 cm
3 Imp gal (US); 4 Imp gal (UK & export)
380 lbs / 173 kg