What Torque Should My Suspension Components Be Tightened To?

Published 01/31/2020

Question:

What torque settings should the bolts be tightened to?

asked by: Jon

Expert Reply:

If you're referring to the bolts that attach the shackles in your suspension system to your # APS4 hangers, you won't need to torque them to a specific rating since over tightening those bolts would squeeze the shackles against the leaf springs and potentially cause binding issues.

When it comes to mounting the hangers, it is strongly recommended that you weld your leaf spring hangers to your trailer frame. Mounting the hangers with a bolt only will not provide a secure connection between the trailer frame and suspension, even if the bolt is torqued down properly. There are some hangers that come with bolt holes on top, but they should be welded as well as bolted.

If you're planning on bolting the hangers in addition to welding, what torque specs used will depend on the size of the bolts being used. For example, 1/2 inch diameter bolts should be torqued between 45 ft/lbs and 70 ft/lbs. A 9/16 inch diameter bolt should be torqued between 65 ft/lbs and 95 ft/lbs and a 5/8 inch diameter bolt should be torqued between 100 ft/lbs and 120 ft/lbs.

expert reply by: Erik B