Siapupy Trailer Shackle & Leaf Spring Kit for 3,500–7,200 lb Tandem Axles — Complete Steel Corrosion-Resistant Set

If you maintain or rebuild utility, boat, or cargo trailers with double-eye leaf springs, this Siapupy kit bundles the common suspension replacement parts you need in one package. Each component is finished to resist corrosion and sized to match common trailer hardware, so mechanics and DIYers can replace worn shackles, equalizers, or bushings without hunting down individual pieces.

What parts are included and how many of each come in the set?

The kit is an all-in-one collection of suspension hardware so you can complete most tandem-axle leaf spring repairs. It contains multiple shackles, equalizers, bolts, locking nuts and bushings to replace both sides of a tandem setup.

• 2 long triangular equalizers with 7-3/4" hole spacing
• 8 shackle straps — 4.38" length with 3-1/8" (3.12") hole spacing
• 8 nylon leaf spring bushings (9/16" I.D., 11/16" O.D.)
• 14 shackle bolts (3-3/8" long) and 14 nylon-insert locking nuts with 9/16"-18 thread

How does the kit fit common trailer leaf spring systems?

The dimensions and thread sizes are chosen to match widely used double-eye leaf spring hardware on utility, boat, and cargo trailers. Check the listed measurements against your trailer’s existing parts to ensure compatibility before installation.

• Designed for axles rated 3,500–7,200 lb (tandem-axle applications)
• Equalizer hole center-to-center: 7-3/4" for standard tandem spring spacing
• Shackle strap spacing: 3-1/8" (3.12") with 4.38" overall strap length
• Bolt length 3-3/8" and common 9/16"-18 thread pitch

What materials and finishes are used, and what performance can I expect?

Components are manufactured from robust steel and treated with a corrosion-resistant coating to extend service life in road, wet or saltwater environments. Nylon bushings reduce metal-on-metal wear and help maintain smooth pivoting under load.

• Steel shackles and equalizers for structural strength
• Corrosion-resistant finish to slow rust in marine and road conditions
• Nylon bushings help reduce friction and wear at pivot points
• Locking nuts resist loosening under vibration

How will this kit simplify repairs or upgrades in my garage or shop?

This packaged set reduces time spent sourcing individual parts and ensures you replace matched components, which helps restore correct suspension geometry. The quantity of pieces lets you service both sides of a tandem axle and keep spares on hand for future maintenance.

• Complete replacement set for tandem-axle leaf spring suspensions
• Matches common factory dimensions for straightforward swaps
• Supplies extra bolts and nuts so you can finish installations without delay
• Works well alongside leaf spring hangers and trailer chassis repairs

Who is this for: The Siapupy Heavy-Duty Trailer Shackle Leaf Spring Kit is intended for trailer owners, repair shops, fleet managers and DIY mechanics who need a reliable set of suspension components for utility, boat or cargo trailers with double-eye leaf springs. If your trailer axle rating falls between 3,500 and 7,200 lb and your existing hardware matches the listed dimensions and threads, this kit gives you the parts and corrosion protection to complete a thorough repair or preventative upgrade.