4 Leaf Springs for Trailer Reviews: 5 Best Options

If your trailer is sagging, bouncing, or just not riding as smoothly as it used to, worn leaf springs are likely the culprit. Upgrading to a quality 4-leaf set can restore load capacity and improve stability on the road.

This guide reviews five of the best 4 leaf springs for trailers, covering different capacities and fitments. Whether you need a direct replacement for a utility trailer or a complete suspension kit for a tandem axle, you’ll find a reliable option here.

Dorman 929-1031 – Direct Replacement 2000lb Capacity

The Dorman 929-1031 is a robust 4-leaf spring designed as a direct replacement for many utility trailers. With a 26-inch length, 4 1/4-inch arch, and a 2000-pound capacity, it’s built to handle heavy loads without sagging. The eye-to-eye design simplifies installation, and Dorman’s reputation for quality aftermarket parts means you get a reliable component that matches original specifications.

This spring is an ideal solution if your current springs are damaged from overloading, collision, or corrosion. Dorman constructs these from quality materials to strict standards, ensuring long service life. Backed by a premier USA-based aftermarket leaf spring provider, you can trust this spring to restore your trailer’s ride and load-carrying ability without guesswork.

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• Direct replacement – these leaf springs are designed to match the fit and function of the original leaf springs on specific vehicles or trailers
• Ideal solution – seamlessly replaces leaf springs damaged by overloading, collision, cracking or corrosion, or are due for replacement
• Durable construction – made from quality materials to strict specifications to ensure reliable performance and long service life
• Trustworthy quality – engineered, manufactured and supported by the premier aftermarket leaf spring provider in the USA
• Support available – every Dorman part is backed by Dorman's ASE Blue Seal Certified technical support team

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Magorfas 4-Leaf Spring Kit – Complete with U-Bolts

The Magorfas single trailer leaf spring kit offers a 1750-pound capacity per spring, making it suitable for 3500-pound trailers. It includes two springs, U-bolts, tie plates, and nuts, providing everything you need for a full axle suspension upgrade. The 25-1/4-inch eye-to-eye length and 1-3/4-inch width fit standard SW4B applications, and the double-eye design simplifies mounting.

Made from 60Si2Mn manganese steel, these springs offer excellent strength and flexibility. The surface features two coats of paint for corrosion resistance, extending service life. The included U-bolt kit (1/2-inch diameter, 5-1/2-inch long) ensures a secure fit on 3500-pound round axles. This all-in-one package saves you time sourcing separate components.

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• Specifications: 4 leaves; Eye to eye length: 25-1/4" ; Free open: 3" ; Width of leaf: 1-3/4" ; Bushing dia: 9/16" ; Leaf thickness: 5/16"
• Fitment Fits for: SW4B; 1750 lb capacity per spring for 3500 lbs trailers. Please check the load rating to ensure that the correct leaf spring is selected.
• High Quality Materials: Our trailer leaf spring kits are made of 60Si2Mn (Manganese Steel) for greater strength, flexibility and hardenability. The surface has 2 coats of paint, which has good corrosion resistance.
• Accessory Kit: 4 x 5-1/2" long U bolts, U bolts dia. 1/2"; 2 x tie plates for 1-3/4" leaf springs; 8 x 1/2"-20 hex nuts. This kit is for 3,500lbs round axle which axle beam dia 2-3/8".
• Trailer Leaf Spring Note: These leaf springs are NOT designed for ANY automobiles of any kind. These will NOT fit cars, trucks, van, or tractors. Please do not buy these UNLESS you are doing so for the trailer they are intended.

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SEHNSUCHT 4-Leaf Spring Kit – Full Suspension Set

The SEHNSUCHT 4-leaf replacement spring kit is designed for SW4B tandem trailer axles, offering 1750 pounds capacity per spring. This comprehensive kit includes not only the leaf springs but also U-bolts, tie plates, equalizers, and hangers. The 25-1/4-inch eye-to-eye length and 1-3/4-inch width match standard 3500-pound axle setups.

Constructed from heavy-duty carbon steel, these springs provide stable load transmission and friction damping. An extra anti-rust coating adds durability against the elements. The included hanger kit (with equalizers and 3-inch tall hangers) simplifies replacing worn suspension components. This is a great choice if you need to rebuild the entire suspension on a tandem trailer.

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• About The Springs: Each spring offer 1,750lbs capacity, suit for standard 3,500lbs trailer axle. Eye to Eye length: 25-1/4 inch, Free open: 3 inch, width of leaf: 1-3/4 inch, 4 leaves, 9/16 inch bushing dia, 2 Bushings Installed for Each Spring, Leaf Thickness 5/16 inch. NOTE: The nut should be tightened horizontally. Failure to do so will affect the final user experience.
• About The Replacement: It will replace for SW4B. The Leaf Springs Made of Heavy Duty Carbon Steel for transmission stability and friction damping, Extra added anti-rust coating for corrosion resistance and long-lasting performance.
• About The Axle U-bolt Kit: This kit include 4 x 5-1/2" long U bolts, U-bolt thread diameter is 1/2",the curvature (inside diameter) of the U-bolt is 2 4/9"; 2 x tie plates for 1-3/4" leaf springs; 8 x 1/2"-20 hex nuts. And this kit used for 2-3/8" dia round trailer axles.(This product offer 2* U-bolt kit).
• About The Trailer Axle Hanger Kit: This kit include 2 x EQ-E1 equalizers, 6 x 3" tall hangers, 8 x shackle straps, 14 x 9/16"-18 x 3" long shackle bolts and locknuts. And this kit used for 1-3/4" leaf springs.
• After-sales service: Any questions after receiving, please contact us freely. Thanks for choosing us!

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Aeagle 4-Leaf Spring – Durable with U-Bolt Kit

The Aeagle 25-1/4-inch 4-leaf spring set provides 1750 pounds capacity per spring, ideal for 3500-pound trailer axles. It comes as a pair of double-eye springs along with a U-bolt kit that includes four 5-1/2-inch U-bolts, tie plates, and nuts. The 1-3/4-inch width and 3-inch free open fit standard round axles, replacing SW4B part numbers.

Each spring features an anti-rust coating for good corrosion resistance, and Aeagle uses high-quality raw materials to ensure strength. The bushings (9/16-inch diameter) are pre-installed, saving installation time. This kit is a straightforward replacement for worn springs on many utility and boat trailers, offering reliable performance without breaking the bank.

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• Replaces for Part Number: SW4B,not fit square axle,Only fit round axle.
• Includes: 2 x 4-Leaves Double Eyes Springs; 3500lbs axle U-bolt kit(Kit includes: 4 x 5-1/2" long U bolts, U-bolt thread diameter is 1/2",the thread length of the U-bolt bolt is 2 inches.the curvature (inside diameter) of the U-bolt is 2 4/9"; 2 x tie plates for 1-3/4" leaf springs; 8 x 1/2"-20 hex nuts). And this kit used for 2-3/8" dia round trailer axles.
• Parameters: 1750 lb capacity per spring for 3,500 lbs trailers; eye to eye length: 25-1/4", free open: 3", width of leaf: 1-3/4", 4 leaves, 9/16" bushing dia, 2 bushings installed for each spring, leaf thickness: 5/16".（Note: The nut should be tightened horizontally. Failure to do so will affect the final user experience）
• Durability: Each of AEAGLE trailer leaf spring kit with anti-rust coating for good corrosion resistance. We always choose raw material with high quality to make our products strong, durable and ensure reliable performance and long use time.
• Quality Assurance: 12-month warranty! Tested before shipping.

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Dorman 929-1002 – Compact 1400lb Capacity Spring

The Dorman 929-1002 is a shorter 4-leaf spring, measuring 20 1/2 inches long with a 3 3/8-inch arch. It offers a 1400-pound capacity, making it suitable for lighter utility trailers. Like its larger sibling, it’s a direct replacement designed to match original fit and function, simplifying installation on specific vehicles or trailers.

This spring is ideal for replacing units damaged by overloading or corrosion. Dorman’s durable construction uses quality materials to ensure reliable performance and long service life. Backed by a premier USA aftermarket leaf spring provider, this spring is a trustworthy choice for smaller trailers that need a precise, factory-spec replacement without excess capacity.

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• Direct replacement – these leaf springs are designed to match the fit and function of the original leaf springs on specific vehicles or trailers
• Ideal solution – seamlessly replaces leaf springs damaged by overloading, collision, cracking or corrosion, or are due for replacement
• Durable construction – made from quality materials to strict specifications to ensure reliable performance and long service life
• Trustworthy quality – engineered, manufactured and supported by the premier aftermarket leaf spring provider in the USA
• Support available – every Dorman part is backed by Dorman's ASE Blue Seal Certified technical support team

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Buyer’s Guide: What to Consider

Choosing the right 4-leaf spring involves matching dimensions, capacity, and hardware. Here are five key factors to consider before buying.

• Capacity: Match the spring's load rating to your trailer's gross axle weight rating (GAWR). Overloading can cause failure; underloading may result in a harsh ride.
• Length and Arch: Measure eye-to-eye length and free arch to ensure proper ride height and alignment. Incorrect dimensions can affect handling and tire wear.
• Leaf Count and Width: More leaves generally increase capacity but stiffen the ride. Standard width is 1-3/4 inches; verify compatibility with your axle and shackles.
• Eye Type: Double-eye springs are common for trailers. Check if your setup requires slipper or fixed ends, and ensure bushing size matches your hangers.
• Material and Coating: Look for high-carbon or manganese steel for durability. Anti-rust coatings extend life, especially if you operate in wet or salty conditions.

Conclusion

Selecting the right 4 leaf spring for your trailer comes down to matching capacity, length, and hardware to your specific setup. For heavy-duty utility trailers, the Dorman 929-1031 offers a robust 2000-pound capacity. If you need a complete suspension rebuild for a tandem axle, the SEHNSUCHT kit provides everything in one box.

For lighter trailers, the Dorman 929-1002 is a precise factory replacement. Whichever you choose, ensure proper installation and always follow torque specifications for safety.