The Triumph T100

Under the Radar


| September/October 2010



triumph t100

The Triumph T100.

Triumph T100
Years produced:
1959-1974
Claimed power: 41hp @ 7,200rpm (1968 T100R)
Top speed: 105mph (1968 T100R)
Engine type: 490cc air-cooled OHV parallel twin
Transmission: 4-speed
Weight: 371lb (wet)
MPG: 45-60 (est.)
Price then/now: $1,199 (1968)/$4,000-$10,000

The Triumph T100 story begins in 1957, with Triumph’s introduction of the 348cc 3TA (“A” for unit construction) “Twenty-One” model, Triumph’s first twin with the transmission built in unit with the engine. Moto-journalists noted that the drivetrain seemed overbuilt for a 350, and that the under-square 58.25mm x 65.5mm cylinder dimensions would allow for a larger displacement version with a bigger bore. They were right.

The unit 5TA Triumph Speed Twin of 1959 arrived with the same 65.5mm stroke as the 350 but with a 69mm bore for 490cc. The sportier Triumph Tiger 100A (T100S from 1961) version arrived the following year. In the U.S., the Triumph T100 was available in two forms: The T100S/R streetbike and the T100S/C, which was more focused toward off-road use. The C model was intended to celebrate Triumph’s success in enduro racing, especially its wins at the famous Jack Pine event, but at first it was little more than a T100S/R with knobby tires — although it did acquire a high-pipe siamesed exhaust around 1964.

Racing development

Though the Triumph 650 Bonneville was Triumph’s best seller in the 1960s, the 500cc T100 and its variants were far more important in motorcycle racing competition. Until 1969, bikes with overhead valves were restricted to 500cc in AMA-endorsed competition events, including the prestigious Daytona 200 mile race, which between 1955 and 1965 had pretty much become a Harley benefit race. But Triumph engineer Doug Hele’s dogged development work on the T100’s performance and handling earned back-to-back wins at Daytona in 1966 and 1967 with Buddy Elmore and Gary Nixon riding.

Not for the first time in motorcycling history, a win in a famous race prompted a new model name. For 1967, the T100R Daytona replaced the T100S/R, and featured a new cylinder head with larger intake valves, racing “Q” cams with radiused followers, dual 1-1/8-inch Amal carburetors and a revised frame/swingarm. The result was 41hp in a bike with a curb weight of just 371 pounds, 25 less than the Bonneville. The Triumph T100 C street scrambler joined it shortly after.

The Triumph T100 C used a single Amal for 38hp and was fitted with a pair of smaller mufflers mounted high on the bike’s left side, a small 5-3/4-inch headlight, no tachometer, and knobby tires — all of which said “desert sled.” Though undeniably purposeful looking, in stock form with its street-oriented suspension the T100 C didn’t really cut it in the truly rough stuff, but made a pleasant “dual-sport” rider.

alan hughes
10/15/2010 12:30:23 PM

The original and true Tiger 100C, was a very limited production bike, 1953. It had twin Amals, sprung hub and all ally. engine. Road tested at 62 in 1st,92 in 2nd, 104 in 3rd. and 116 in top. ! down, 3 up.






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