SR4

The Radical SR4 features motorcycle-derived inline-four producing 194-230 horsepower depending on specification (Honda CBR1000RR 998cc or Suzuki Hayabusa 1,340-1,600cc variants) through six-speed sequential transmission and rear-wheel-drive at 530kg curb weight establishing exceptional power-to-weight ratio. Entry-level specification includes steel space frame chassis with composite bodywork, pushrod suspension with adjustable dampers front and rear, limited-slip differential, racing brake package, motorcycle-derived engine mounted mid-ship, lightweight construction prioritizing track performance, and open-cockpit configuration with minimal weather protection.

SR4 represents Radical Sportscars entry-level offering positioned below SR3 best-seller, creating accessible track-day platform utilizing proven motorcycle powertrain technology reducing acquisition and operating costs compared to purpose-built racing engines while maintaining legitimate circuit performance through extreme lightweight construction. The poor sales performance compared to SR3 demonstrates market preference for slightly larger more powerful variant, though SR4 establishes cost-effective introduction to serious track car ownership for enthusiasts progressing from conventional sports cars toward dedicated competition machinery, with British manufacturer establishing lightweight formula creating street-legal track cars competing in club racing and time attack events worldwide, maintaining motorcycle engine philosophy pioneered by Caterham and Ariel while adding comprehensive aerodynamic package and purpose-built racing chassis creating accessible performance previously requiring significant budget or fabrication skills.