The company's first car, built by Phil Abbott in 1996, the Radical 1100 Clubsport, was based on a Kawasaki motorcycle engine placed inside a small open-cockpit chassis. The cars were intended to run in the 750 Motor Club's races under the Sports 2000 category, with founders Abbott and Hyde driving.
In 1999, Radical had built enough 1100 Clubsports that they decided to create a one-make series based around the car. Backed by the British Racing and Sports Car Club, the series featured identical cars that were open to anyone who owned an 1100 Clubsport. The same year, Radical debuted their second model, the Prosport. Available with Kawasaki or Suzuki engine up to 1500 cc in displacement, the Prosports were even more powerful and faster than the Clubsports, and included F3-size slick tyres and an adjustable rear wing. The cars were also brought to the United States for the first time, for use in the SCCA D-Sport class in 2000.
Launched in 2001, Radical's next creation was the two-seater SR3, a car which could compete in international racing, such as the FIA's C3 class. The car uses a Suzuki-based engine tuned by Powertec (now RPE) which offered 1300 cc or 1500 cc versions and a maximum of 260 hp (190 kW) in the latter. An enclosed gear drive unit was developed specifically for the car to replace the traditional motorcycle engine chain drive.
In 2006, Radical would make its largest leap into international motorsport with the development of the SR9, a complete Le Mans prototype in the LMP2 class. Official partner Rollcentre Racing would debut the car with success in the Le Mans Series and 24 Hours of Le Mans, and SR9s in the hands of independent teams would contest the 24 Hours of Le Mans a further four times.
