The following article highlights top leaf spring kits designed for 3,500 lb trailer axles. Each option includes a 4-leaf or 5-leaf design and a 25-1/4″ eye-to-eye length, offering reliable support for lighter to mid-weight trailers. The selections emphasize durability, corrosion resistance, and compatibility with 2-3/8″ round axles. Use the buying guide to compare key factors and ensure proper fit for your trailer’s suspension system.
| Product | Brand | Leaf Count | Capacity Per Spring | Eye To Eye | Notes |
|---|---|---|---|---|---|
| Youxmoto 3500lb Single Trailer Axle Suspension Kit | Youxmoto | 4 | 1750 lb | 25-1/4″ | Includes U-bolts and hanger kit |
| Magorfas Trailer Leaf Spring 4 Leaf Set (Set 2) | Magorfas | 4 | 1750 lb | 25-1/4″ | Includes U-bolts and hardware |
| Magorfas Tandem Trailer Leaf Spring 4 Leaf Set (Set 4) | Magorfas | 4 | 1750 lb | 25-1/4″ | Hanger and U-bolt kit included |
| Youxmoto Single Trailer Leaf Spring 4 Leaf | Youxmoto | 4 | 1750 lb | 25-1/4″ | Includes 3,500 lb axle U-bolt kit |
| SEHNSUCHT Replacement for SW4B 4 Leaf Set | SEHNSUCHT | 4 | 1750 lb | 25-1/4″ | Coated for corrosion resistance |
Note: All products listed are designed for 3,500 lb trailer axles with a 2-3/8″ round axle beam and a 25-1/4″ eye to eye measurement. Installation requires proper alignment and torque specs. Check compatibility with your specific trailer model before purchase.
Youxmoto 3500lb Single Trailer Axle Suspension Kit
This 4-leaf spring kit is designed for 3,500 lb trailers and provides a replacement option with a total capacity of 7,000 lbs across the axle when using a pair. Eye-to-eye length is 25-1/4″, free open is 3″, and leaf width is 1-3/4″. Each spring uses a 9/16″ bushing diameter and 5/16″ leaf thickness. The kit includes 4 U-bolts (5-1/2″ long, 1/2″ diameter), 2 tie plates for 1-3/4″ leaves, and 8 hex nuts. This set fits SW4B axles with a 2-3/8″ beam diameter. Tightening direction is important to maintain performance.
Magorfas Trailer Leaf Spring 4 Leaf Set (Set 2)
Magorfas offers a 4-leaf design with 25-1/4″ eye-to-eye length, 3″ free open, 1-3/4″ leaf width, and 9/16″ bushing diameter. Each spring holds 1,750 lbs, totaling 3,500 lbs per axle session when paired. Built from 60Si2Mn manganese steel, the springs receive two coats of paint for corrosion resistance. A caution is advised to verify the correct load rating for your trailer to ensure the right spring configuration is selected. Includes necessary mounting hardware in the kit.
Magorfas Tandem Trailer Leaf Spring 4 Leaves (Set 4)
The tandem Magorfas set features four leaves per spring, with an eye-to-eye length of 25-1/4″ and a 3″ free open. Leaves are 1-3/4″ wide with 5/16″ thickness and 9/16″ bushings, designed for SW4B fitment. Each spring provides 1,750 lb capacity, suitable for 3,500 lb trailer axles. The kit includes a hanger and U-bolt hardware. As with similar products, verify that the axle and frame are compatible with the selected leaf springs to avoid improper alignment.
Youxmoto Single Trailer Leaf Spring 4 Leaf
This Youxmoto option mirrors the 25-1/4″ eye-to-eye, 3″ free open configuration, with 1-3/4″ leaf width and 9/16″ bushings. It is a direct replacement for SW4B and supports 3,500 lbs trailers with a 2-3/8″ axle beam diameter. The included U-bolt kit is designed for quick installation, comprising 4 U-bolts, 2 tie plates, and 8 hex nuts. As noted, the alignment of nuts must be managed horizontally to maintain proper function.
SEHNSUCHT Replacement for SW4B 4 Leaf Set
SEHNSUCHT offers a robust replacement kit for SW4B with four leaves per spring and a 25-1/4″ eye-to-eye dimension. Each spring supports 1,750 lbs, totaling 3,500 lbs per axle. The springs use heavy-duty carbon steel and receive anti-rust coatings for corrosion resistance. The included U-bolt kit and hardware ensure straightforward installation on 2-3/8″ axles. The parts are designed to provide consistent damping and stability under load, with attention to proper nut torque and horizontal tightening during assembly.
Buying Guide: Key Considerations When Choosing Leaf Springs for a 3500 Lb Axle
Understanding how to select the right leaf spring set depends on several factors beyond just capacity. Consider the following perspectives to balance strength, durability, and compatibility:
- Load rating and compatibility: Confirm the axle type (round 2-3/8″ beam) and ensure each spring is rated for 1,750 lbs, providing a total capacity compatible with a 3,500 lb axle. Match eye-to-eye length and free open height to your trailer’s mounting points.
- Leaf count and material: Four-leaf designs typically offer a balance of strength and flexibility; five-leaf options increase load capacity marginally and stiffness. Materials like manganese steel (60Si2Mn) enhance durability and resistance to wear.
- Bushings and hardware: Check bushings diameter (commonly 9/16″) and ensure U-bolts and tie plates are included or readily purchasable. Correct hardware sizing is essential for a secure installation and safe operation.
- Corrosion protection: Look for coatings or paints that resist rust in exposed environments. This is especially important for trailers used in salt air, rain, or humid climates.
- Installation guidance: Some kits offer complete installation hardware and hangers; others may require additional components. Verify that the kit includes U-bolts, nuts, and plates suitable for the leaf width (1-3/4″).
- Aircraft- or automotive-grade standards: While most trailer kits are automotive-grade, confirm that the springs meet standard tolerances for long-term performance and safe load handling.
- Maintenance and replacement cycles: Leaf springs typically outlast multiple trailers but can fatigue in high-use conditions. Consider kits with repairs parts readily available and straightforward replacement processes.
- Application scope: Some kits are designed specifically for tandem suspension (dual springs per side) and others for single-axle configurations. Ensure you select the setup that matches your trailer’s axle arrangement.