During the 1958-59 European racing season, the Cooper was the only rear-engined Grand Prix contender, and within three years, the front-engined cars had virtually disappeared. Many consider the 2.5-litre Formula 1 Cooper-Climax (engine was made by Coventry Climax) to be the most successful Grand Prix racer Britain ever produced; it took over where the front-engined Vanwall racer had left off. The Cooper-Climax brought England the Constructors' Championship twice running, provided the mount for Jack Brabham's two World Championships, initiated a design trend followed throughout Europe, and eventually influenced American track-racing car design. In the 1960 season, Brabham won five Grand Prix in a row in a Cooper, and Coopers won a total of ten Grand Prix that year.
Cooper won back-to-back World Championship titles in 1959 and 1960. During the early 1960s, the team suffered as delays for the new 1.5-liter BRM and Coventry Climax Formula 1 engines forced the use of Formula 2 derived Coventry Climax FPF 4-cylinder power plants. The 120-degree V6 4-cam engined 'Sharknose' Ferraris would dominate the handicap and underpowered Coopers. The British teams did all they could to compensate for the modest power. The cars became smaller than ever before, even though the new Formula regulations imposed a minimum weight limit, higher than that of the 2.5-liter class of the previous year.
There were only two dedicated works team cars built, chassis number F1/10/61 and F1/11/61. F1/11 was campaigned by Sir Jack's team-mate Bruce McLaren.
Cooper's engineers were able to slim down the original gearwheels and pack in six where once lived five. This helped the driver's balance the narrow torque band, especially in wet weather.
The T55's made their racing debut at the Aintree '200' race. The 6-speed cars finished first in second in the heavy rain, with Jack Brabham crossing the line first, followed by Bruce McLaren.
At Monaco, Brabham was in midfield before retiring with ignition trouble. At the Dutch Grand Prix, Brabham finished in sixth and then a fourth at Brands Hatch on June 3rd in 1961. In the wet at the British Grand Prix in Aintree, Brabham finished fourth.
For the German Grand Prix, the new T55-based racer, the unique T58, was readied which brought an end to the T55 chassis number 10's works career.
The T55 cars accumulated 13 finishes from 19 starts during the 1961 Formula 1 season. The highlight was the debut victory at Aintree by Jack Brabham.
In early 1962, F1/10 was brought to New Zealand by Sir Jack, where it was campaigned in the Tasman series. There, it was given a 2.7 and 2.5-liter Climax FPF engines to suit. At Longford, Tasmania, Sir Jack finished second in this car.
The car was then sold to Tasmanian John Youl who campaigned the car through 1964. Since then, the car has been well preserved in private collections and used in various vintage events.
In 2009, this monoposto was offered for sale by Bonhams Auction at the Quail Lodge Resort and Golf Club in Carmel, CA. It was estimated to sell for $250,000 - $350,000. As bidding came to a close, the lot had been sold for the sum of $216,000 inclusive of Buyer's Premium.Also photographed at :