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

The ACT BM13-HDR4 Heavy Duty Race Rigid 4-Pad Clutch Kit is engineered for maximum race-day performance, combining ACT's most popular Heavy Duty pressure plate with a high-ceramic 4-pad rigid race disc. This kit is designed specifically for race use, delivering aggressive engagement, rapid shifts, and proven reliability at high RPM — all backed by ACT's industry-leading quality standards.

Heavy Duty Pressure Plate:

• Exclusive diaphragm design increases clamp load, reduces deflection, and maximizes clutch life
• All diaphragms undergo a rigorous four-stage heat-treating process for consistent, high-performance output
• Precision cover stampings provide superior rigidity and dimensional consistency
• 100% clamp load tested — every unit verified before it ships

4-Pad Rigid Race Disc:

• Constructed with select, high-quality ceramic friction materials for outstanding heat tolerance and maximum grip
• Chrome-moly hub is heat-treated for added strength and long-term durability
• Lightweight, rigid design enables quicker, more decisive gear changes
• Aggressive engagement character — faster shifts with a more pronounced engagement feel
• Especially well-suited for smaller disc sizes found in smaller displacement engines

Precision Balancing & Quality Control:

• Dynamically computer spin-balanced to within 0.25 oz-in for smooth operation across the entire RPM range — twice as precise as typical OEM production clutches (0.50 oz-in)
• Carefully engineered, precisely assembled, and accurately balanced for consistent, repeatable performance

Important Notes:

• Recommended for race use only — not intended for daily street driving
• Rigid disc design may increase spline wear over time
• Moderate friction life; extended through ACT's exclusive diaphragm design
• Pedal effort increase of approximately 15–40% compared to a stock clutch (Heavy Duty range)
• Break-in: ACT race discs typically require only a few firm slips to properly lap in the friction surfaces prior to racing