Trailer U Bolt Kit 5-1/2 in for 3,500 lb Axle - Heavy Duty Fit

In this review the Trailer U Bolt Kit is evaluated as a straightforward replacement kit for trailers with a 3,500 lb round axle. The bottom line: this kit is for anyone who needs a reliable, correctly sized set of U-bolts and hardware to secure a 2-3/8 in axle to 1-3/4 in leaf springs, and the biggest reason to buy is its correct fit and durable steel construction that simplifies brake alignment and suspension clamping.

Key Features

• Exact fit for 3,500 lb axles: The U-bolts are 5-1/2 in long and sized to work with a 2-3/8 in axle beam, which removes guesswork when matching parts.
• Complete hardware set: The kit includes 8 U-bolts, 16 1/2-20 hex nuts and 4 tie plates so installers have everything needed for both sides of a tandem or single axle setup.
• Durable steel construction: Robust materials give the clamping hardware the strength required to keep the axle and leaf spring assembly stable under load.
• Corrosion resistant: The finish helps resist rust and corrosion so the hardware maintains function in trailer conditions over time.
• Improves braking and alignment: Proper clamping of the axle helps maintain brake orientation and consistent suspension geometry for safer towing.

Who It's For

This kit is aimed at DIY trailer owners, small fleet operators, and repair shops replacing worn U-bolts on trailers that use a 2-3/8 in round axle rated around 3,500 lb. It is particularly useful when the installer wants a full replacement pack with tie plates and sufficient nuts for both sides without sourcing parts separately.

Those who should look elsewhere include owners of trailers with non-round or larger diameter axles, different leaf spring widths, or specialized applications that require custom-length U-bolts or alternative thread sizes. If your axle or springs do not match the listed dimensions, choose a kit sized to your hardware.

Pros & Cons

Pros

• Good fit for 2-3/8 in axle beams and 1-3/4 in leaf springs, reducing installation adjustments.
• Complete set of hardware makes replacements faster and more convenient for both sides of a trailer.
• Customers report solid thread quality and bolt strength, which increases confidence in clamping security.

Cons

• Limited to the specific axle and spring sizes listed, so it is not a universal kit for all trailers.
• Finish is corrosion resistant but installers in very harsh marine environments may prefer stainless alternatives.

Specifications

Application	3,500 lb round axle
Axle beam diameter	2-3/8 in
U-bolt size	8 x 5-1/2 in long, 1/2 in diameter
Thread	1/2-20 hex nuts, 2 in thread pitch
Tie plates	4 plates for 1-3/4 in leaf springs
Quantity	2 pack (8 U-bolts, 16 nuts, 4 tie plates)

Our Verdict

The Trailer U Bolt Kit is a practical, value-oriented replacement pack for trailers with a 2-3/8 in axle beam and 1-3/4 in leaf springs. It offers the correct sizing, complete hardware, and durable steel build needed to restore secure clamping and consistent brake alignment, making it a sensible buy for DIYers and shops replacing worn U-bolts.

Frequently Asked Questions

Will these U-bolts fit my axle?
They fit when your axle beam diameter is 2-3/8 in and your leaf springs are the 1-3/4 in width noted; match those sizes before purchasing.

Does the kit include hardware for both sides?
Yes, the pack includes 8 U-bolts, 16 nuts and 4 tie plates which cover both sides of a single axle or one side of a tandem setup as needed.

Are these stainless steel?
The kit is built from durable steel with a corrosion-resistant finish; for marine or very corrosive environments consider stainless alternatives.