Trailer Leaf Spring 4 Leaf Double Eye 1750 lb Capacity - Set of 2

In this review the focus is on a pair of trailer leaf springs intended for single-axle 3500 lb trailer setups. The bottom line: these 4-leaf, double-eye springs are a straightforward replacement option when a trailer is sagging, bouncing excessively, or carrying uneven loads, and they deliver the core purpose-restoring suspension capacity-reliably. Our review finds the springs best for trailer owners who need a direct, robust swap for SW4B-fit axles and who value corrosion resistance and solid spring strength over cosmetic finishes.

Key Features

• 4-Leaf Construction: Provides layered strength and controlled flex for consistent load support on a 3500 lb axle when installed as a pair.
• 1750 lb Capacity per Spring: Each spring is rated to carry 1750 lb, which together supports standard 3500 lb trailer axles when load ratings match the trailer.
• 25-1/4' Eye-to-Eye Length: The 25-1/4' eye-to-eye length makes these springs a direct fit for applications specified as SW4B, simplifying replacement.
• 60Si2Mn Manganese Steel: Built from heat-treatable manganese steel for improved strength, flexibility, and resistance to permanent deformation under load.
• Two-Coat Painted Surface: The painted finish provides basic corrosion resistance to extend service life in typical trailer environments.
• Simple Bushing Size: With a 9/16' bushing diameter they fit common mount hardware on compatible trailer axles.

Who It's For

These springs are aimed at trailer owners, maintenance shops, and DIY mechanics who need a reliable, like-for-like replacement for worn or damaged springs on 3500 lb trailer axles that accept SW4B fitment. They suit utility trailers, small equipment trailers, and boat trailers where restoring ride height and load handling is the priority.

These are not for automobiles, trucks, vans, tractors, or any vehicle other than trailers; buyers seeking suspension parts for road vehicles should look elsewhere. Also check load ratings carefully-if your trailer carries loads above the rated capacity, consider a heavier-duty spring or a different suspension solution.

Pros & Cons

Pros

• Good build quality from 60Si2Mn steel gives reliable spring strength and flexibility under load.
• Direct fit for SW4B setups with standard 25-1/4' eye-to-eye sizing and 9/16' bushing diameter.
• Two coats of paint improve corrosion resistance for longer service life on trailered equipment.
• Customers report straightforward installation and consistent functionality as replacement springs.

Cons

• Not suitable for any automobiles or on-road vehicle suspension uses; strictly trailer-only.
• Value perceptions vary among customers, so cost versus long-term durability may be judged differently.

Specifications

Leaves	4
Eye-to-eye length	25-1/4 in
Free open	3 in
Leaf width	1-3/4 in
Bushing diameter	9/16 in
Leaf thickness	5/16 in
Load capacity	1750 lb per spring (3500 lb axle)

Our Verdict

This pair of 4-leaf, 1750 lb trailer springs is a practical, no-frills replacement for trailers that use SW4B fitment and need restored ride height and load support. The manganese steel construction and painted finish make them a durable option for routine trailer use, and they represent sensible value for anyone needing a direct swap rather than an upgrade to a heavier system.

Frequently Asked Questions

Will these fit my trailer?
They fit trailers specified for SW4B with a 25-1/4 in eye-to-eye requirement; confirm the axle and mounting hardware match the 9/16 in bushing diameter.

Can these be used on cars or trucks?
No, these springs are designed only for trailers and are not suitable for automobiles, trucks, vans, or tractors.

How much weight does each spring support?
Each spring is rated at 1750 lb, so a matched pair supports a 3500 lb axle when installed and matched to the trailer's load requirements.