ACT ZM15-HDR4 Heavy Duty Race Rigid Clutch Kit - 4-Pad

The ACT ZM15-HDR4 is a Heavy Duty Race Rigid 4-Pad Clutch Kit engineered for maximum performance in demanding race environments. This kit pairs ACT's most popular Heavy Duty pressure plate with a ceramic 4-pad rigid race disc, delivering aggressive engagement and faster shifts for drivers who demand the absolute best from their drivetrain.

Pressure Plate Features:

• Exclusive diaphragm design increases clamp load, reduces deflection, and maximizes clutch life
• All diaphragms undergo a four-stage heat-treating process for consistent, high-performance operation
• Precision cover stampings provide rigidity and consistency under load
• 100% clamp load tested and dynamically computer balanced for smooth, high-RPM reliability

4-Pad Rigid Race Disc Features:

• High-quality ceramic friction materials for superior heat tolerance and maximum performance
• Chrome-moly hub is heat-treated for enhanced strength and long-term durability
• Lightweight rigid design enables quicker shifts and reliable service
• Well-suited for smaller disc sizes found in smaller displacement engines

Precision Balancing:

• All ACT clutch assemblies are computer spin balanced to within 0.25 oz-in — twice the precision of typical OEM clutches balanced to 0.50 oz-in
• Ensures smooth operation across the full RPM range

Performance Notes:

• Expect a 15–40% increase in pedal effort over stock (Heavy Duty range)
• Engagement is more aggressive than street-oriented discs; recommended for race use
• Race discs typically require only a few hard slips to lap in friction surfaces prior to normal use

Backed by ACT's industry-leading one-year warranty, the ZM15-HDR4 delivers race-proven reliability and precision for drivers who won't compromise on performance.