Best Leaf Springs For 3500 lb Axle: 8 Options Compared

#1 · Best Overall

1. TRAILER SUPPLIES Suspension Kit

Best for: All-in-one single-axle rebuild.

Why it ranks #1: Pairs two 1,750 lb springs with U-bolts and hangers; it specifies 25-1/4-inch springs and direct replacement fit for SW4B and LIB-401-DE.

Two 1,750-pound springs arrive with U-bolts and hanger hardware, enabling a complete single-axle suspension restoration or build from one package. The 25-1/4-inch double-eye springs are identified as replacements for Dexter SW4B and LIB-401-DE models, giving buyers specific reference points for assessing replacement fit.

Each 1.75-inch-wide, four-leaf spring supports 1,750 pounds, with the pair rated for a 3,500-pound axle. The included APUBR-1 U-bolt kit is specified for 2-3/8-inch round axles, while the package list also names tie plates, nuts, hangers, shackle straps, bolts, and lock nuts. Bringing these components together can simplify sourcing for a single-axle job. The stated application includes utility, boat, landscape, and cargo trailers; the kit is for single-axle suspension work.

Skip it if you have a square axle; the U-bolt kit is specified for 2-3/8-inch round axles.

A practical match for owners rebuilding a single 3,500-pound axle on a utility, boat, landscape, or cargo trailer. Check the round-axle U-bolt specification and the listed replacement references before selecting it.

Listed on Amazon as: Single Trailer Leaf Spring Suspension Kit – 4-Leaf Double Eye, 1,750 lb Cap per Spring for 3,500 lb Axle – Includes Hanger & U-Bolt Kit, 25-1/4" Length, Fits SW4B

#2 · Most Complete Hardware

2. Aeagle Suspension Kit

Best for: Complete round-axle replacement kit.

Why it ranks #2: Includes two 1,750 lb springs, axle U-bolts, tie plates, hangers, and shackle straps; its stated fit is limited to round axles.

A complete suspension package pairs two four-leaf double-eye springs with U-bolts and a hanger kit, enabling a broader single-axle replacement than springs alone. Each spring is rated at 1,750 pounds for a 3,500-pound axle, and the included axle hardware is specified for 2-3/8-inch round axles.

The 25-1/4-inch springs are 1.75 inches wide and made from 60Si2Mn manganese steel, whose stated stable elasticity and shock absorption support a smoother, steadier trailer ride. Electroplated paint provides a rust-resistant coating. The kit also includes four 5-1/2-inch U-bolts, tie plates, nuts, hangers, and shackle straps, so buyers restoring a single axle have multiple suspension components together. Its round-axle limitation matters: the U-bolt kit is specified for 2-3/8-inch round axles, not square axles.

Skip it if you have a square axle; this kit's U-bolts are specified only for 2-3/8-inch round axles.

Choose it if you want springs and major hanger and axle hardware in one package for a 3,500-pound single trailer axle. Its key boundary is axle shape: the supplied U-bolt kit is for a 2-3/8-inch round axle.

Listed on Amazon as: AEagle 4 Leaf 1750lb Capacity Double Eye Spring for 3500lb Trailer Axle, 25-1/4" Length, 1.75" Width, 3" Free Open & U-Bolt & Hanger Kit, Suspension Kit Replaces SW4B, 2PCS

#3 · Best Complete Kit

3. dreamdragon Suspension Kit

• Weight: 36.6 lb
• Package Dimensions: 30 x 15 x 4 in

Best for: Nylon-bushed complete suspension kit.

Why it ranks #3: Combines springs rated at 1,750 lb each with U-bolts and hangers; specified spring length is 25-1/4 inches for a standard 3,500 lb axle.

Nylon-bushed, 1,750-pound springs arrive with U-bolts and hangers, enabling a more comprehensive single-axle suspension replacement in one package. The four-leaf springs measure 25-1/4 inches eye to eye and are specified for standard 3,500-pound axles, with the U-bolt kit intended for 2-3/8-inch round axles.

Each spring has a 3-inch free opening and 1-3/4-inch width, while the 9/16-inch bushing diameter and nylon bushings give buyers mounting details to compare and arrive pre-specified for the assembly. The included U-bolts are matched to 3,500-pound axles with a 2-3/8-inch round beam. Hangers are also included, making the kit relevant to a broader suspension job than springs alone. The stated application is light- to medium-duty trailer use.

Skip it if you have a square axle; its U-bolt kit is specified for 2-3/8-inch round beams.

A suitable package for light- to medium-duty trailer owners replacing a 3,500-pound single-axle suspension and wanting springs, U-bolts, and hangers together. Its stated U-bolt application is limited to a 2-3/8-inch round axle.

Listed on Amazon as: dreamdragon Single Trailer Axle Suspension Kit – 3,500 lbs 4 Leaf Spring, U-Bolts & Hangers Included

#4

4. Youxmoto Suspension Kit

• Weight: 28.7 lb

Best for: Round-axle spring and U-bolt set.

Why it ranks #4: Includes two 1,750 lb, four-leaf springs and U-bolts for a 2-3/8-inch round axle, with 25-1/4-inch length and 9/16-inch eye ID.

This package combines a pair of 1,750-pound, four-leaf double-eye springs with U-bolts, tie plates, and nuts, enabling spring replacement alongside key axle-fastening hardware. Its stated application is a 3,500-pound round axle with a 2-3/8-inch beam, and the springs are identified as SW4B replacements.

The springs measure 25-1/4 inches long and 1-3/4 inches wide, with a 9/16-inch eye diameter, giving buyers several dimensions to compare with their existing setup. Four 5-1/2-inch U-bolts, two tie plates, and eight nuts are included for the specified round axle. The product also notes that nuts must be tightened horizontally; following that installation detail matters because the listing says incorrect tightening affects use. Its extra rust-proof coating is intended for harsh environments.

Skip it if you need hangers and shackle straps included; TRAILER SUPPLIES' complete kit lists both.

Consider this set for SW4B replacement on a 3,500-pound round axle when springs and U-bolt hardware are the priority. Its listed components do not include hangers or shackle straps, so account for those separately.

Listed on Amazon as: 3500lb Single Trailer Axle Suspension Kit 1750lb Leaf Springs & Ubolt Kit; Pair of Trailer Leaf Spring 4 Leaf Double Eye, 25-1/4" L, 1-3/4" Width, 9/16 Eye I.D

#5

5. SEHNSUCHT Leaf Spring Kit

• Weight: 28.8 lb
• Package Dimensions: 28.49 x 12.14 x 4.96 in

Best for: Dimension-specific SW4B spring pair.

Why it ranks #5: The pair is rated for 3,500 lb per axle and lists 25-1/4-inch length, 3-inch arch, and 1-3/4-inch width, plus a U-bolt.

Pre-installed bushings and a detailed dimension set make this spring pair useful for buyers matching an SW4B-style suspension. Each four-leaf spring is rated at 1,750 pounds, with a 25-1/4-inch eye-to-eye length, 3-inch free arch, and 1-3/4-inch leaf width for a 3,500-pound axle application.

The listing specifies a 9/16-inch bushing inner diameter, two bushings pre-installed per spring, and 5/16-inch leaf thickness, helping buyers compare key mounting and spring dimensions before replacement. The pair supports up to 3,500 pounds per axle, and the direct-replacement reference is SW4B. Installation requires attention to the stated instruction to tighten nuts horizontally; the listing says improper tightening affects use. The package title mentions a U-bolt, but the provided component details do not spell out a full hanger kit.

Skip it if you want a clearly itemized hanger kit; TRAILER SUPPLIES' complete suspension kit lists hangers and shackle straps.

This pair fits buyers matching SW4B dimensions for a 3,500-pound axle and wanting pre-installed bushings. Observe the horizontal nut-tightening instruction, and note that a complete hanger kit is not specified in the supplied details.

Listed on Amazon as: 2 Pieces of Replacement for SW4B 4 Leaf Trailer Leaf Spring, 3500lb Single Trailer Axle Suspension Kit, 25-1/4" Length with 1750lb Capacity Double Eyes Leaf Springs and U-Bolt

#6 · Best Replacement Match

6. LIBRA Trailer Leaf Spring

• Weight: 50.5 lb
• Package Dimensions: 27.5 x 6.5 x 4 in

Best for: Multi-reference spring replacement.

Why it ranks #6: Lists several cross-references including SW4B and gives a 1,750 lb rating, 25-1/4-inch length, 3-inch arch, and nylon bushings.

A broad set of replacement references—including SW4B, 72-42, LIB-401-DE, and UNA212—makes this spring pair useful for owners identifying an existing suspension by part designation. Each spring is rated at 1,750 pounds for a standard 3,500-pound trailer axle and has a 25-1/4-inch eye-to-eye length.

The four-leaf springs have a 3-inch free opening, 1-3/4-inch leaf width, and 9/16-inch bushing diameter, providing several dimensions for comparison during a replacement. Nylon bushings are installed, so the set arrives with those components already in place. Its pair configuration and stated per-spring rating match a standard 3,500-pound axle application. The supplied details describe springs rather than a full suspension kit, so buyers planning a broader rebuild should account for other hardware separately.

Skip it if you need a full suspension hardware package; dreamdragon's kit lists U-bolts and hangers with its springs.

Choose this pair when its listed dimensions and replacement references match your existing 3,500-pound trailer suspension. It is a spring-focused option, not the supplied choice for buyers seeking U-bolts and hangers in the same kit.

Listed on Amazon as: LIBRA Trailer Leaf Spring 4 Leaf Double Eye 1750lb Cap for 3500lbs Axle PK4

#7

7. Magorfas Trailer Leaf Spring

• Weight: 24.3 lb
• Package Dimensions: 28.3 x 12 x 4.7 in

Best for: Replacement spring pair for SW4B.

Why it ranks #7: A two-spring set lists 1,750 lb capacity per spring for a 3,500 lb trailer axle and a 25-1/4-inch length matching SW4B.

A pair of 25-1/4-inch, four-leaf double-eye springs rated at 1,750 pounds apiece gives buyers a clearly specified replacement option for a 3,500-pound trailer axle. The title identifies SW4B fit, making this set relevant to owners seeking matching springs rather than a listed full suspension hardware kit.

The stated capacity is 1,750 pounds per spring, or 3,500 pounds for the trailer axle, which helps buyers compare the set with the axle rating. Its 25-1/4-inch length and double-eye configuration provide concrete dimensions and mounting style to check against existing springs. The supplied information identifies a set of two, but does not list U-bolts, hangers, or installation hardware, so the package is best considered a spring replacement rather than a complete suspension rebuild kit.

Skip it if you need U-bolts and hangers in the package; TRAILER SUPPLIES' complete kit lists those components.

This pair suits owners replacing springs on a 3,500-pound trailer axle who can use the stated SW4B fit and 25-1/4-inch length. It is not the listed choice for buyers needing a full hardware kit.

Listed on Amazon as: Trailer Leaf Spring 4 Leaf Double Eye 1750 lbs Cap for 3500 lbs Axle Suspension 25-1/4" Length fits for SW4B – Set 2

#8

8. GEARCESS Leaf Spring

Best for: Manganese-steel replacement pair.

Why it ranks #8: The pair is described as SW4B-compatible, with 25-1/4-inch length, 1-3/4-inch width, and 1,750 lb capacity per spring.

GEARCESS uses 60Si2Mn manganese steel for its four-leaf springs, a material the listing associates with strength, flexibility, and hardenability. The pair is specified for SW4B applications, with a 1,750-pound rating per spring and 25-1/4-inch eye-to-eye length for a 3,500-pound trailer axle.

The 3-inch free opening, 1-3/4-inch width, 9/16-inch bushing diameter, and 5/16-inch leaf thickness give buyers concrete measurements to compare with the original springs. Two coats of paint are listed on the surface, providing a stated protective finish. The package includes two trailer leaf springs with accessories, but the supplied details do not identify those accessories individually. That makes this a fit-focused spring replacement rather than a clearly itemized full axle hardware package.

Skip it if you need every included hardware component identified; TRAILER SUPPLIES lists its U-bolts, hangers, straps, and fasteners.

This pair suits owners matching SW4B dimensions who want manganese-steel springs for a 3,500-pound axle. Choose it for spring replacement, while recognizing the listing does not itemize the included accessories as a full hardware kit.

Listed on Amazon as: Leaf Spring 4 Leaf 1750lbs 3500lb Trailer Axle