Leaf Spring U-Bolt Kits

ATS Springs offers leaf spring U-bolt kits for heavy, medium, and light-duty trucks, as well as select automotive applications. Our U-bolts provide the critical clamping force required to properly secure the axle to the leaf spring pack, making them the foundation of a safe and reliable suspension installation.

Easy Selection & Expert Assistance

Choosing the correct U-bolt size can be challenging due to variations in axle diameter, spring width, and suspension setup.

If you need help, Contact Us and “Just Ask Bob” or call 1-888-943-8287. Our suspension specialists will help you select the correct U-bolt for your specific application.

Available Grades, Bends & Kit Contents

Available Grades

Grade 5
Grade 8

Available Bends

Round bend
Square bend
Semi-round bend

What’s Included

(2) U-bolts
Deep nuts
Thick hardened washers

Important Installation Information

Do not reuse old U-bolts — fatigue and stretching from prior torqueing can compromise clamping force
Proper torque is critical for safety and performance
Recommended torque specifications are available on our U-Bolt Torque Page
All ATS U-bolts are custom bent from straight rods at time of order
U-bolts are special-order items and non-returnable

How to Measure Leaf Spring U-Bolts

(Round, Square & Semi-Round)

Correct measurements ensure proper fit, clamping force, and long-term suspension reliability.

Measure Rod Diameter (“A”)

To estimate rod diameter, use the socket size that fits your existing U-bolt nuts:

11/16″ socket → 7/16″ rod
3/4″ socket → 1/2″ rod
13/16″, 7/8″, or 21mm socket → 9/16″ rod
15/16″ socket → 5/8″ rod
1-1/16″ or 1-1/8″ socket → 3/4″ rod
1-5/16″ socket → 7/8″ rod

Measure Inside Width (“B”)

Measure the distance between the inside faces of the U-bolt legs. This ensures proper clearance around the axle tube.

Measure Leg Length (“C”)

Measure the length of each leg from the bend to the thread end. This ensures enough thread engagement for washers and nuts once installed.

Why New U-Bolts Matter

U-bolts stretch slightly when torqued during installation. Reusing old U-bolts can result in:

Improper torque retention
Axle movement
Premature suspension wear
Unsafe driving conditions

Installing new U-bolts during any leaf spring or axle service is strongly recommended.

Need Help Selecting the Right U-Bolts?

ATS Springs is here to help. If you’re unsure about sizing, grade, or bend style, give us a call or contact us online and we’ll make sure you get the correct U-bolts for your suspension setup.

Leaf Spring U-Bolt Kits