Tie Down Eng U-Bolts

Tie Down Engineering U-Bolts: Built for Trailers, Engineered for Corrosion Resistance

When it comes to securing spring hangers, winch posts, bunk brackets, and crossmembers to a trailer frame, the U-bolt is one of the most critical — and most overlooked — pieces of hardware in the assembly. Tie Down Engineering has long been a trusted name in trailer and marine hardware, and their lineup of U-bolts reflects the same engineering-first philosophy that defines the brand across its broader catalog.

Zinc-Plated and Hot-Dip Galvanized Options

One of the standout features of Tie Down Engineering's U-bolt selection is the choice of protective finish. Their kits are available in both zinc-plated and hot-dip galvanized configurations, each engineered for corrosion resistance in demanding environments. The zinc-plated U-bolts come complete with flat washers and nyloc nuts for a secure, rattle-resistant fit, while the hot-dip galvanized variants include flat washers, lock washers, and standard nuts — providing a heavier coating ideal for repeated water exposure, especially on boat trailers that see regular saltwater or freshwater launches.

Square and Round Profiles in Multiple Sizes

Tie Down Engineering offers U-bolts in both square and round bend profiles, allowing them to match different trailer frame geometries and mounting bracket styles. Whether you need a square kit like the 3/8"-16 x 3-1/8" x 4" pair or a round galvanized unit in a 3/8" x 1-3/4" x 4-3/16" dimension, the lineup covers a wide range of rod widths — including 7/16 in., 1/2 in., and 3/8 in. — paired with appropriate thread pitches (13, 14, and 16 threads per inch respectively) to suit industry-standard trailer components. Kits are available both individually and in pairs to match your specific replacement or build-out needs.

Purpose-Built for Trailer Frame Mounting

Tie Down Engineering's U-bolts are specifically designed for mounting brackets, spring hangers, winch posts, and crossmembers to trailer frames — the kinds of connections that endure road vibration, load stress, and environmental exposure on every trip to the water or job site. The included hardware in each kit eliminates the need to source nuts and washers separately, making these kits a convenient and reliable solution for both DIY trailer maintenance and professional builds.

A Brand with Deep Trailer Hardware Roots

Tie Down Engineering produces an extensive range of trailer components — from axles and brakes to rollers and couplers — making their U-bolts a natural complement to a complete trailer system. With operations spanning over 825,000 square feet and a vertically integrated manufacturing model, Tie Down controls quality at every step from steel fabrication to final assembly. Browse the full Tie Down Engineering brand page for their complete trailer hardware lineup, or explore the full U-bolts category to compare options across brands and sizes.