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Motorcycle Investor mag

Speed dreams

(by Ian Falloon, Mar 2022)

Triumph's first Bonneville got off to a surprisingly rocky start

On a bright morning in September 1956, Texan Johnny Allen arrived at the Bonneville Salt Flats in Utah. The diminutive Allen slid into the cockpit of a streamlined two-wheeler, nicknamed the Texas Ceegar.

Inspired by the fuel ‘drop tanks’ of a Mustang fighter plane this amalgamation of American and British expertise carried a Texas star on its nose, and the Triumph name on its side.

With power supplied by a nitro-methane-fed 650cc Thunderbird parallel twin, the cigar-shaped streamliner tore across the salt flats at an average of 214.40mph (345.188 km/h). Although this was clearly a new world record the FIM world body didn’t recognise it as the US AMA at that time.

Triumph boss Edward Turner was unperturbed. He had the Texas Ceegar air freighted to the Meriden factory in England, first to appear in a BBC TV sports program, then for display on the Triumph stand at the annual London Earls Court Motorcycle Show.

All this publicity fuelled the demand for a higher performance version of the production T110 650cc twin. But Turner’s distrust of racing as a promotional tool was well known and initially the company’s policy was unchanged.

Rather than provide a higher performance model Triumph initially offered a limited number of higher performance components for purchase. This included pistons, valves, camshafts, valve springs and a megaphone exhaust. The release of a splayed port “Delta” twin carburettor cylinder head for the 500cc Tiger T100 in 1957 also saw demand for a 650cc version, particularly from American customers.

For 1958 Triumph finally offered a twin carburettor 650cc splayed inlet port cylinder head as an optional replacement for the T110. This provided the T110 the performance and reliability it finally needed to win the important Thruxton 500 production race, with a young Mike Hailwood teaming with Dan Shorey for the win.

The twin carb heads were also successful in America, Triumphs took eight of the first 10 places in the 1958 Big Bear Run Desert Enduro.

While motorcycle sales were still strong in the UK, at this time Triumph was also the most popular imported motorcycle in America. The company relied heavily on the US market and eventually Turner bowed to US pressure to build a production twin carburettor 650.

This would be the Bonneville, the motorcycle that would define Triumph for the next three decades and continue to do so today. As it was considerably more affordable than a Norton 650SS, and faster than a BSA 650, the Bonneville became the favoured mount for the young British working class.

Despite some initial problems, of all the British twins it was the lightest, fastest and most elegant.

Along with a splayed-port cylinder head and twin Amal carburettors, the 650cc engine featured a high-lift camshaft and high-compression pistons. The crankshaft was also a stronger one-piece forged type with centrally bolted cast-iron flywheel.

Ostensibly a modified T110 Tiger, the first Bonneville was a no holds barred sportster, but the engine wasn’t without problems. Vibration was still a concern, and the single frame-mounted racing type remote float bowl carburettor proved problematic. Hard acceleration and braking caused fuel surging and subsequent misfiring. Triumph offered a remedy kit later in the season but problems persisted.

Rushing the Bonneville into production meant it retained much of the original T110 equipment. This included touring-type valanced fenders and an ungainly headlight nacelle. These not only seemed incongruous on a high-performance sporting motorcycle, but also didn’t appeal to the American market, where riders preferred the stripped-down look. To Americans the first Bonneville simply didn’t look right.

Also not right was the initial colour scheme. Fancying himself an artist, Turner presided over style and colour combinations and back in 1957 had introduced two-tone colour schemes. These worked well on Lambretta scooters and some ageing British cars like the Hillman Minx, so Turner adapted the style for motorcycles.

For the Bonneville Turner chose a Tangerine/Pearl Grey colour scheme, now known as the “Tangerine Dream.” Some have also suggested the Bonneville’s two-colour finish was intended to suggest the colours of the Utah Salt Flats landscape. Regardless, these colours proved controversial and unpopular; many Tangerine 1959 Bonnevilles in the US ended up unsold, and were listed again for 1960. Ironically the 1959 Bonneville is now viewed as a rarity and the original colour scheme considered desirable.

It didn’t take long for Meriden to realize the failure of the initial colour scheme and in April 1959 the factory changed the colours for UK and general export machines. Royal (also known as Azure) Blue replaced the Tangerine, but the rest of the machine was unchanged. These new colours would continue for 1960.

Meriden called the Bonneville the T120 to indicate it was capable of 120 miles per hour, but compared with the usual publicity fanfare it was announced almost apologetically.

There was originally no official brochure and Triumph almost treated the Bonneville as an unwelcome addition to the family. While the “120” designation may have been illusory, the Bonneville was still one of the fastest motorcycles available in 1959.

Contemporary road tests saw top speeds in the region of 185 km/h but you had to be a brave rider to sustain an early Bonneville at those speeds. The early Bonneville suffered from Turner’s obsessional cost cutting, and the frame, unbraced swingarm, and weak brakes were stretched to the limit.

But the late 1950s was still a good time for Triumph. Then riding a wave, the Bonneville legend was established at a time of strong sales on both sides of the Atlantic.

Dealers in America had been crying out for a twin-carb 650 Triumph for years and it was also what the high performance motorcycle rockers in England wanted.

Only in Australia was the Bonneville not as popular. Reeling from negative publicity, motorcycling was an endangered activity at this time and very few early Bonnevilles were sold here.

As with many collectables, it is the first model that has become the most sought after. The 1959 T120 Bonneville is the one that created the legend.

More on Meriden era Bonnevilles at AllMoto

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