ACT Heavy-Duty Clutch Kits are high quality products guaranteeing superior functionality and efficiency. These products provide a clamp load increase up to 50 percent, increasing torque capacity.

Key Features:

• Spline Size (Inches): 1
• Disc Type: Race Disc
• Spline Count: 22
• Product Weight (lbs.): 9.7
• Torque Capacity (ft./lbs.): 320
• Light to moderate pedal effort, aggressive engagement, increased gear rattle
• Moderate friction life, extended by ACT's exclusive diaphragm design, rigid design may increase spline wear
• Carefully engineered, precisely assembled, accurately balanced, uses select ceramic friction materials for high heat tolerance and maximum performance
• Recommended for race use only
• 100% clamp load tested and dynamically computer balanced for smooth high RPM reliability

ST1-HDR4 kit features ACT's most popular Heavy Duty pressure plate. ACT Heavy Duty pressure plates use exclusive diaphragm design to increase clamp load, reduce deflection and maximize clutch life. All diaphragms endure a four-stage, heat-treating process for unparalleled performance. ACT pressure plates have precision cover stampings to provide rigidity and consistency. ACT's 4-pad rigid race discs are made with high quality, ceramic friction materials. The chrome-moly hub is heat-treated for strength and durability. The lightweight, rigid design allows for quicker shifts and smooth, trouble-free service. With the 4-pad rigid race disc, engagement is harsher, but shifting is faster. The 4-pad rigid race disc is well-suited for the smaller disc sizes in smaller engines.
Since 1994, Advanced Clutch Technology has specialized in performance clutches and flywheels. All products are made from the highest quality materials and then necessarily tested to ensure they perform to the customers' expectations.

Vehicle Fitment Table

FAQ

Will this fit my vehicle?
Please verify your year, make, model, position, and any fitment notes using the compatibility table above before purchase.

What part number is this?
The listed part number is ST1-HDR4.

Is this product designed for direct replacement?
Yes. This product is intended to match the compatible vehicle applications listed in the fitment table.

Should I confirm fitment before ordering?
Yes. Always compare your original part, position, and vehicle details with the fitment table before ordering.

Common Searches

• HD/Race Rigid 4 Pad for Saturn SC
• ST1-HDR4 fitment
• ACT HD/Race Rigid 4 Pad
• 1991–1992 Saturn SC HD/Race Rigid 4 Pad
• ACT ST1-HDR4 replacement