The Lotus 18 was the first mid-engined car designed by Colin Chapman and was designed for use by Lotus in Formula Junior, Formula 2, and Formula 1. Introduced for the 1960 season, the car was built using Chapman's classic design principles: lightweight, simple and rigid. F1 cars initially used the 2.5 Coventry Climax 4-cylinder engine from the Lotus 16 with 240 hp, but with the updated regulations in 1961, it was then replaced by a 1.5 L Climax FPF Mk II. For a transmission, Lotus opted to re-utilize the Lotus 16 sequential gearbox and adapt it to the 18 with a couple of improvements. The suspension was also a new design, ensuring a light, nimble machine that was very successful in the championships it took part in. The 18 was the first Lotus to claim a victory in F1, in the 1960 Monaco Grand Prix, driven by Stirling Moss, and helping Lotus secure second place in the 1960 F1 Championship. Approximately 30 chassis were made for F1 and F2, while about 110 were made for Formula Junior.