Tough jobs need tougher springs. The P528 28” Plug-End Extension Spring is a reliable, high-tension solution designed for heavier 1-piece, tilt-up, or canopy-style garage doors. Built to replace Holmes-brand springs, it’s ideal for doors that need extra lifting power and long-lasting durability.
Whether you’re working on a home upgrade or a professional repair, this spring has the strength and specs to get the job done right.
Perfect Fit for Heavier Garage Doors
Use 2 P528 springs for doors weighing 105–175 lbs
Use 4 P528 springs for doors weighing 200–350 lbs
Engineered for smooth lift and balanced tension
Specs & Features
Total coil length: 28 inches
Outer diameter: 1-5/8 inches
Wire gauge: 0.207” (No. 5 wire)
Initial tension: 135–145 lbs
Max stretch: 22 inches
Compatible with C-hooks or W-hooks (sold separately)
Backed by a 1-year manufacturer warranty
💡 Installation Tip: For safe and efficient performance, always replace extension springs in sets and verify proper tension before operating the door.
