In its early days, the company encouraged its customers to race its cars, and it first entered Formula One through its sister company Team Lotus in 1958. A Lotus Formula One car driven by Stirling Moss won the marque's first Grand Prix in 1960 at Monaco. Moss drove a Lotus 18 entered by privateer Rob Walker. Major success came in 1963 with the Lotus 25, which – with Jim Clark driving – won Team Lotus its first F1 World Constructors Championship. Clark's untimely death – he crashed a Formula Two Lotus 48 in April 1968 after his rear tyre failed in a turn in Hockenheim – was a severe blow to the team and to Formula One. He was the dominant driver in the dominant car and remains an inseparable part of Lotus's early years. That year's championship was won by Clark's teammate, Graham Hill.