The three remaining FW chassis were renamed the Williams FW for 1975, and revised by Ray Stokoe, but by now the design was becoming outdated. They were resdesignated the FW01, FW02 and FW03 despite being of the same type. The oldest car, the FW01 (original IR chassis "01") continued to be used only as a spare car, and the FW02 (IR chassis "02") was only used for the first three races of the season. The team used the slightly newer FW03 throughout 1975 while they worked on a replacement, the FW04, which was ready for the Spanish Grand Prix. Williams was operating on a low budget and was occasionally even forced to buy used tyres from other teams. Both Merzario and Laffite stayed with the team for 1975.