Torque Specs for Attaching Leaf Springs

Updated 09/14/2025 | Published 01/23/2022

Products Featured in This Question

U-Bolt Kit for Mounting 3,500-lb, Round Trailer Axles - 5-1/2" Long U-Bolts

(2120)

$77.04

Question:

What’s the torque spec on the bolts attaching these leafs to the trailer and shackle?

asked by: Darrin

Expert Reply:

You will need the U-Bolt Kit item # APUBR-1 to use the 4-Leaf Double-Eye Spring for 3,500-lb Trailer Axles - 27" Long item # SP-210275. The kit uses 1/2 inch diameter nuts that you will want to torque them down to about 70 foot pounds.

expert reply by: Jerred H

Jsmie

9/13/2025

What about 4000lb axle with double eye 26" long leaf springs with 1/2 inch bolt. Whats all those torque along with the shackle

Jerred H.

9/14/2025

@Jsmie 50 ft- lbs for both the MORryde Suspension Upgrade Kit for Tandem Axle Trailers item # MR46ZR with 2-1/4" shackles or item # MR98ZR with 3-1/8" shackles. These kits come with the bronze bushings, wet bolts and shackle straps. You'll want to go with the kit closest to the size of your current shackle straps.