12-15K 5″ Tube U-Bolt Kit – 3/4″ Rod Diameter

Description

The 12-15K U-Bolt Kit secures heavy trailer axles to leaf springs. It fits 5 inch round trailer axle tubes and 3 inch wide leaf springs, the common setup on 12,000 lb and 15,000 lb trailer suspensions.

This heavy-duty kit includes four U-bolts, two tie plates, and eight lock nuts to mount one axle. The U-bolts use a 3/4″-10 thread diameter and measure about 9-5/8″ long to wrap around the large axle tube and spring stack.

The kit works with trailers that use leaf spring suspension systems. You install it after you place the leaf springs beneath the axle tube. Then you slide the U-bolts over the axle tube. Next, you set the tie plates under the spring stack and thread the nuts on. Tightening the nuts evenly pulls the axle tightly to the springs. Proper torque helps keep the assembly secure under load.

This U-bolt kit fits many heavy utility trailers, equipment trailers, gooseneck trailers, livestock trailers, and car haulers with 12K–15K rated axles. Match it to tapered or straight round axle housings with 5-inch outer diameters.

The 3″ spring width matches typical heavy-duty 3″ leaf springs, including slipper and multi-leaf setups found on high-capacity tandem axles. A solid U-bolt clamp prevents axle shift, reduces suspension noise, and improves handling.

Install this kit whenever you perform a spring replacement, axle rebuild, or suspension upgrade. New U-bolts stand up better to load cycles and road shock than reused hardware. Torque the nuts in a crisscross pattern to avoid distortion.