Best Leaf Springs For 3500 lb Axle: Compare 10 Options

#1 · Best Overall

1. Youxmoto Single Axle Kit

• Weight: 28.7 lb

Best for: Round-Axle Spring And U-Bolt Kit.

Why it ranks #1: Specifies a 3,500 lb round axle with a 2-3/8-inch beam and includes four-leaf 1,750 lb springs, U-bolts, tie plates, and nuts.

A 3,500-pound round-axle kit pairs two 1,750-pound-capacity, four-leaf springs with U-bolts and tie plates, enabling a spring-and-axle mounting replacement in one package. Its 25-1/4-inch length and 1-3/4-inch width identify the spring dimensions, while the listing specifies a 2-3/8-inch axle beam.

The double-eye springs have 9/16-inch eye inner diameter, and the included U-bolts are 5-1/2 inches long with 1/2-inch diameter. Together with tie plates for 1-3/4-inch springs, these pieces support mounting the springs to the specified 2-3/8-inch round axle. The listing identifies SW4B replacement fit and calls for horizontal nut tightening, a useful installation detail to follow. A rust-proof coating is also specified for handling harsh environments.

Skip it if you have a square axle or need a spring-only pair; the included mounting hardware is specific to a 2-3/8-inch round axle.

A practical match for a SW4B replacement on a 3,500-pound trailer with a 2-3/8-inch round axle, this package includes spring-mounting hardware. Check axle shape and diameter before choosing it; the listing excludes square axles.

Listed on Amazon as: Youxmoto 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

#2 · Best Tandem Kit

2. Aeagle Tandem Hanger Kit

• Weight: 78.8 lb
• Package Dimensions: 29 x 15 x 6 in

Best for: Tandem Round-Axle Suspension Kit.

Why it ranks #2: Supplies four 1,750 lb springs plus U-bolt and tandem hanger hardware; its 25-1/4-inch length and 1-3/4-inch width are specified.

Four 1,750-pound-capacity springs and a tandem hanger kit give this Aeagle package a broader replacement scope than a spring pair alone. Its 25-1/4-inch double-eye springs are specified for SW4B replacement on round axles, with 3-inch free open and 1-3/4-inch width noted for fit assessment.

The included U-bolt and tandem hanger kit makes this a package for addressing spring mounting alongside the four springs, which are rated for 3,500-pound trailers. Each spring has four leaves, 5/16-inch leaf thickness, and two installed 9/16-inch bushings. Aeagle specifies 60Si2Mn manganese steel and an electroplated rustproof coating; the listing associates the spring material with stable elasticity and the coating with rust resistance. Horizontal nut tightening is required.

Skip it if you have a square axle; Aeagle AELS0003Q2 is also specified for round axles, so choose a square-axle-compatible kit instead.

For a tandem suspension replacement on a 3,500-pound trailer, this package combines four springs with hanger and U-bolt hardware. It is specifically for round axles, so axle shape and the listed spring dimensions are key fit boundaries.

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

#3 · Most Complete Hardware

3. Aeagle Single Hanger Kit

Best for: Complete Single-Axle Hanger Kit.

Why it ranks #3: Pairs two 1,750 lb springs with U-bolts, tie plates, hangers, and shackle straps for a single-axle setup on a 2-3/8-inch round axle.

A complete single-axle hanger kit accompanies the two 1,750-pound springs, giving this Aeagle package a wider installation scope than a spring-and-U-bolt set. It specifies SW4B replacement for round axles and includes hangers, shackle straps, tie plates, and U-bolts for a 3,500-pound axle.

The package lists two 3-inch hangers, two 2.1-inch hangers, four shackle straps, U-bolts, tie plates, and nuts, supporting a more comprehensive single-axle suspension rebuild. Its springs are four-leaf double-eye replacements, and the listing specifies a 2-3/8-inch round axle application. Aeagle identifies alloy steel and a rustproof electroplated finish. These details help buyers plan the mounting components and assess the axle-shape boundary before beginning installation.

Skip it if you have a square axle; Aeagle AELS0003Q2 is another round-axle-only option, so seek a square-axle-specific kit.

This package suits buyers rebuilding a single-axle suspension who need springs, hangers, shackle straps, and axle hardware together. Its stated fit is for a 2-3/8-inch round axle, making axle shape and diameter essential boundaries.

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

#4 · Best Specified Fit

4. SEHNSUCHT Tandem Kit

Best for: Dimension-Specified SW4B Replacement.

Why it ranks #4: Lists 25-1/4-inch eye-to-eye length, 1-3/4-inch width, 9/16-inch bushings, and 1,750 lb capacity per spring for a tandem kit.

A detailed spring specification—25-1/4-inch eye-to-eye length, 3-inch free open, and 1-3/4-inch width—makes this SEHNSUCHT kit useful for buyers matching an SW4B replacement. Each four-leaf spring is rated at 1,750 pounds for a standard 3,500-pound trailer axle, and the package includes installation hardware.

Each spring has two installed bushings with a 9/16-inch diameter, plus 5/16-inch leaf thickness; these measurements help compare the replacement against existing suspension parts before installation. The double-eye layout and SW4B replacement reference further narrow the intended fit. The supplied installation hardware supports a kit-based repair, while the listing's horizontal nut-tightening instruction gives a specific assembly detail to observe. Carbon steel is the stated spring material.

Skip it if you need a spring-only pair without installation hardware; Youxmoto LFLS0002-LYF is listed as a pair of springs.

This kit suits buyers replacing SW4B-style springs on a standard 3,500-pound trailer axle who want dimensions and installed-bushing details stated upfront. Match those measurements to the existing suspension, and follow the horizontal nut-tightening instruction.

Listed on Amazon as: 4 Leaf of Replacement for SW4B Trailer Leaf Spring, 3500lb Tandem Trailer Axle Suspension Kit with 1750lb Capacity Double Eyes Leaf Springs, 2U-Bolt and Hanger Kit

#5

5. Aeagle Spring U-Bolt Kit

• Weight: 28.8 lb
• Package Dimensions: 28.4 x 12.2 x 4.9 in

Best for: Round-Axle Pair With Tie Plates.

Why it ranks #5: Includes two 1,750 lb four-leaf springs and U-bolt hardware for a 2-3/8-inch round axle; it explicitly excludes square axles.

This Aeagle pair combines two 1,750-pound four-leaf springs with U-bolts, tie plates, and nuts, giving a single-axle replacement package its mounting hardware. The springs are specified for SW4B replacement, while the kit calls out 2-3/8-inch round axles and excludes square axles.

The 25-1/4-inch double-eye springs have 1-3/4-inch width and 3-inch free open, dimensions that help assess whether the replacements match an existing setup. Four 5-1/2-inch U-bolts, two tie plates, and eight hex nuts are included for mounting on the specified round axle. Aeagle identifies 60Si2Mn manganese steel and an electroplated rustproof coating, connecting the material and finish to stable elasticity and rust resistance.

Skip it if you have a square axle; Aeagle AELS0004Q2 also specifies round-axle use, so neither listed Aeagle kit suits that axle shape.

Choose this package for a SW4B-style, single-axle replacement when the axle is round and measures 2-3/8 inches. Its pair of springs and mounting hardware cover a focused installation, but the stated fit excludes square axles.

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

#6

6. SEHNSUCHT Single Axle Kit

• Weight: 37.9 lb
• Package Dimensions: 29 x 13 x 4.5 in

Best for: Single-Axle Spring And Hardware Kit.

Why it ranks #6: Offers two 1,750 lb springs with 25-1/4-inch eye-to-eye length, 1-3/4-inch width, and 9/16-inch bushings, plus U-bolt and hanger kit.

A two-spring replacement set rated at 1,750 pounds per spring targets a standard 3,500-pound single trailer axle. SEHNSUCHT specifies SW4B replacement, 25-1/4-inch eye-to-eye length, and 3-inch free open, while including U-bolt and hanger hardware for a broader repair package.

The four-leaf double-eye springs measure 1-3/4 inches wide and use two installed 9/16-inch bushings apiece, giving useful checkpoints for comparing the replacement to existing suspension parts. Their 5/16-inch leaf thickness and carbon-steel construction are also stated. The included U-bolt and hanger kit can support mounting work beyond swapping springs alone. SEHNSUCHT specifically instructs that the nuts be tightened horizontally, a detail to account for during assembly.

Skip it if you are replacing a tandem suspension and need four springs; Magorfas MFLS0005Q4 is listed as a four-spring tandem set.

This SEHNSUCHT set fits buyers tackling a single-axle SW4B-style replacement who want spring and mounting hardware together. Compare its stated dimensions with the existing suspension, and account for the horizontal nut-tightening instruction during installation.

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

#7

7. Youxmoto Spring Pair

• Weight: 23.7 lb

Best for: SW4B Spring-Only Pair.

Why it ranks #7: A two-spring replacement set rated 1,750 lb per spring, with 25-1/4-inch length, 1-3/4-inch width, and 9/16-inch eye diameter.

Two four-leaf springs rated at 1,750 pounds each provide a focused SW4B replacement pair for a 3,500-pound axle. The 25-1/4-inch eye-to-eye length, 3-inch free open, and 1-3/4-inch width give buyers concrete dimensions to compare when replacing existing trailer springs.

The pair uses double eyes with 9/16-inch bushings and 5/16-inch leaf thickness, helping buyers check key suspension dimensions before installation. Youxmoto identifies the springs as direct replacements for SW4B and states the combined application as a 3,500-pound trailer. Strong steel plate and an extra rust-proof coating are also specified, with the coating intended to handle harsh environments. This listing is a spring pair, rather than a bundled U-bolt or hanger kit.

Skip it if you want mounting hardware bundled with the springs; Aeagle AELS0003Q2 lists a pair with U-bolts and tie plates.

A suitable choice for buyers replacing a pair of SW4B-style springs on a 3,500-pound trailer, especially when matching dimensions matters. Plan separately for mounting hardware, since the supplied listing identifies this as a spring pair.

Listed on Amazon as: Youxmoto Pair of Trailer Leaf Spring 4 Leaf Double Eye, 1750lbs Cap for 3500lbs Axle, 25-1/4" L, 1-3/4" Width, 9/16 Eye I.D (2 Bushings), Fits for SW4B

#8

8. Magorfas Tandem Set

• Weight: 80.8 lb
• Package Dimensions: 29 x 15 x 6.5 in

Best for: Tandem Spring And Hanger Package.

Why it ranks #8: Provides four 1,750 lb springs for a 3,500 lb trailer and lists shackle bolts, locknuts, and eight U-bolts, though spring dimensions are less detailed.

Four 1,750-pound-capacity springs make this Magorfas set a tandem-axle package for a 3,500-pound trailer setup, with hanger and U-bolt hardware included. The 25-1/4-inch double-eye springs are identified as fitting SW4B, giving buyers a specified spring style and replacement reference for planning the suspension work.

The four-spring quantity suits a tandem arrangement, while the included hanger and U-bolt kit brings mounting components into the same package. Eight 5-1/2-inch U-bolts are listed, along with fourteen 9/16-inch-by-3-inch shackle bolts and locknuts. Those hardware details help buyers plan a broader suspension installation rather than sourcing only springs. Each spring is rated at 1,750 pounds; the listing describes the set for 3,500-pound axles and round trailer axles.

Skip it if you are replacing springs on one axle and need only a pair; Magorfas MFLS0003Q2 is listed as a two-spring set.

Choose this set when replacing springs across a tandem trailer suspension and you want hanger and U-bolt hardware bundled with four springs. Its stated 1,750-pound capacity is per spring, so assess the axle and suspension setup accordingly.

Listed on Amazon as: Tandem Trailer Leaf Spring 4 Leaf Double Eye 1750 lbs Cap for 3500 lbs Axle Suspension, Hanger & U-Bolt kit 25-1/4" Length fits for SW4B, for Round Trailer Axles- Set 4

#9

9. Magorfas Spring U-Bolt Set

• Weight: 29.2 lb
• Package Dimensions: 29.2 x 12.7 x 5.6 in

Best for: Two-Spring Set With U-Bolts.

Why it ranks #9: The two-spring set is rated 1,750 lb per spring and includes four 5-1/2-inch U-bolts, but its listing provides fewer fit dimensions.

Four included 5-1/2-inch U-bolts distinguish this Magorfas two-spring set, making it a spring replacement option with axle-fastening hardware included. The listing rates each four-leaf double-eye spring at 1,750 pounds for a 3,500-pound trailer and gives a 25-1/4-inch length with SW4B fit.

A pair of springs is suited to replacing the two springs on a single axle, while the four U-bolts provide hardware for securing the assembly. Magorfas specifies 1/2-inch U-bolt diameter, alongside a 1,750-pound capacity per spring. The 25-1/4-inch length and double-eye construction identify the spring style, and the SW4B reference helps narrow replacement selection. The listing does not provide further spring dimensions in the supplied specifications.

Skip it if you need documented spring width and bushing measurements; SEHNSUCHT LS0004 lists both dimensions for its two-spring kit.

A straightforward option for a single-axle replacement when a pair of SW4B-style springs and U-bolts are the priority. The supplied details specify spring length and U-bolt diameter, so buyers needing additional spring measurements should compare carefully.

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

#10

10. Magorfas Spring Pair

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

Best for: Basic Two-Spring Replacement Set.

Why it ranks #10: The pair is listed at 1,750 lb capacity per spring for a 3,500 lb axle, but supplied hardware and detailed dimensions are not stated.

A two-spring set rated at 1,750 pounds per spring targets a 3,500-pound trailer axle, with 25-1/4-inch length and SW4B fit stated by Magorfas. Its four-leaf double-eye format gives buyers a defined replacement spring style for a focused suspension change.

The pair quantity suits replacing two springs on a single axle, while the 1,750-pound per-spring rating identifies the stated capacity for a 3,500-pound trailer application. The 25-1/4-inch length and SW4B reference provide useful comparison points when assessing a replacement. Magorfas also lists a 2,500-pound-per-spring capacity for 5,000-pound trailers, but buyers focused on a 3,500-pound axle should use the stated 1,750-pound rating for this application.

Skip it if you need a pair bundled with U-bolts and tie plates; Aeagle AELS0003Q2 lists those axle-mounting parts with its springs.

A fit for buyers seeking a two-spring SW4B replacement for a 3,500-pound trailer axle, with the spring length and capacity stated. Plan the installation around the mounting components your suspension requires.

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