ACTs 4-pad, spring-centered race discs are made with high quality, ceramic friction materials that produce 28 percent more friction and torque capacity over organic materials. The spring-center construction properly dampens torsional vibrations for quieter operation and resists failure even under harsh conditions. ACT spring retainers utilize wraparound spring windows and thicker retainer stampings to provide spring support, reduce stress concentrations and increase strength and reliability. The heavy duty torsional dampening springs are stronger in most cases than standard springs and are provided in the best sizes and spring rates to suit the application. With the 4-pad, spring-centered race disc engagement is harsher but shifting is faster. The 4-pad spring-centered race disc features a heat-treated spring steel drive plate and is well-suited for the smaller disc sizes in smaller engines. All ACT race discs are certified as meeting SFI Specification 1.1 and are legal in all racing organizations that require SFI certification.