Tiger U-bolt Product Function

A U-bolt serves in four critical roles:  
  • Primarily, the truck U-bolts provide the force required to clamp the lead spring and related components firmly together. In addition to the leaf spring, these components include the top plate, axle seat, axle and bottom plate.
  • The properly installed u-bolt eliminates any flexing of the lead spring in the are between the U-bolts. This particularly critical since the hole for the centerbolt in each leaf acts as a stress concentration which would lead to rapid leaf breakage if spring flexing was not totally eliminated by the U-bolt clamping force.
  • By firmly clamping the spring to the axle seat the horizontal forces acting on the centerbolt are greatly reduced which in turn prevents shearing of the centerbolt.
  • Proper clamping of the spring by the truck U-bolts provides the desired spring stiffness and contributes to maintaining the vehicle ride height and handing characteristics as originally specified for the vehicle

Tiger U-bolt’s high tensile strength that attribute to its durability

its high material hardness and its conformance to OEM standards makes it’s the right choice for your U-bolt needs.

Types of U-bolt

TYPES OF U-BOLT: Three basic types of bends are used on U-bolts depending on the suspension design and the shape of the mating parts:


U-bolt Torque is very important and always use new U-bolts when doing spring work

U-Bolt provide the clamping force needed to hold the spring to the axle. U-bolts have proven to be the easiest, most economical and most reliable way of attaching spring to an axle.

Whenever springs are replaced or repaired, the U-Bolts should be replaced. The threads on most U-bolts are not cut, they are rolled. When bolts are tightened, the threads are deformed by the nuts. Obtaining the proper torque (clamping force) CAN NEVER be achieved when RESUING OLD U-BOLTS. A USED U-BOLT may have suffered from fatigue as well as excessive stress since achieving accurate torque with commonly used impact wrenches is very difficult.

As previously explained, the primary function of the U-bolt is to maintain the clamping force on the spring assembly and related parts. Since clamping force is a function of the condition of U-bolt, the damaged threads of the used U-bolt will make reaching this force very difficult.

Considering that REUSING U-BOLTS CAN LEAD TO PREMATURE SPRING FAILURE and other suspension damage, it is clear that U-BOLTS SHOULD NEVER BE REUSED.



1. High Tensile Strength that attribute to its durability

2. High material hardness that can handle right torque without thread deformation

3. Can help to extend the life of Leaf spring due its high tensile strength and high material hardness

Tiger Ubolt Competitor



At 100 N-m the thread of competitor’s U-bolt encountered thread deformation

Tiger U-bolt



At 100 N-m the thread of U-bolt did not encounter thread deformation