ACT BM13-HDR4 Heavy Duty Race Rigid 4-Pad Ceramic Clutch Kit

The ACT BM13-HDR4 Heavy Duty Race Rigid 4-Pad Clutch Kit is engineered for demanding race applications where maximum power transfer and lightning-fast shifts take priority over street drivability. This kit pairs ACT's Heavy Duty pressure plate with a 4-pad rigid ceramic race disc, delivering aggressive engagement and superior high-heat performance designed specifically for competition use.

Heavy Duty Pressure Plate:

• Features ACT's exclusive diaphragm design to increase clamp load, reduce deflection, and maximize clutch life
• All diaphragms undergo a rigorous four-stage heat-treating process for long-lasting, consistent performance
• Precision cover stampings provide structural rigidity and dimensional consistency
• 100% clamp load tested for verified performance before leaving the factory

4-Pad Rigid Ceramic Race Disc:

• High-quality ceramic friction materials selected for exceptional heat tolerance and maximum performance
• Chrome-moly hub is heat-treated for added strength and resistance to spline wear
• Lightweight, rigid design enables quicker, more precise gear changes
• 4-pad configuration is ideally suited for smaller disc sizes used in smaller displacement engines
• Aggressive engagement character — harsher than a sprung disc, but with faster, more direct shifting

ACT Quality Standards:

• All clutch assemblies are dynamically computer spin-balanced to within 0.25 oz-in for smooth, reliable high-RPM operation — twice as precise as typical OEM production tolerances
• Carefully engineered, precisely assembled, and accurately balanced for race-ready reliability

Race Use Characteristics:

• Light to moderate pedal effort with aggressive, positive engagement
• Increased gear rattle due to rigid disc design — expected behavior in a race application
• Moderate friction material lifespan; ACT's exclusive diaphragm design helps extend service life, though the rigid hub design may accelerate spline wear over time

Recommended for race use only. The BM13-HDR4 is not intended for street or daily driving applications. ACT race discs require only a few firm engagement cycles to lap in the friction surfaces before normal race use.