The car was designed by Simtek owner and technical director Nick Wirth, along with the chief designer of Simtek Research, Paul Crooks. It was a direct evolution of the 1994 season car, the S941. In order to secure a firm foothold in the sport following a traumatic season in which Roland Ratzenberger was killed at Imola whilst driving the S941, the team designed the S951 to be straightforward and uncomplicated.