Increasing Length of Suspension Shackle Strap When Upgrading Trailer Suspension

Updated 03/09/2016 | Published 03/08/2016

Question:

My trailer currently uses 2inch shackles. Im looking at doing an axle/spring/wheel/tire upgrade to change the single axle 3500 lbs trailer to a 5000 lbs single axle trailer. I wont be replacing the spring hangers. Im wondering though what difference would there be for me in using either the 2inch sized shackle straps that my trailer currently uses vs the 3-1/4inch straps used in this kit. I understand that in this kit the straps are thicker, but other than that what differences would there be here? Is there a reason for me to get a new 2inch straps or will the 3-1/4inch straps work just as well? For reference, the springs Im using and the ones I will be using are 25.25inch double eye leaf springs. Ill be going from a 4 leaf to a 5 leaf variety.

asked by: Adrian G

Expert Reply:

If you're not changing the spacing of the spring hangers and you're using leaf springs that are the same length (just a greater capacity) than your current springs, you would not want to change the length of your shackle straps. A longer strap would add more play into the system, which could cause the back of the leaf spring to bang into the underside of the trailer. You'll want to continue using a 2 inch shackle straps.

You're increasing the capacity of the axle, suspension, wheels and tires but you'll want to make sure the rest of the trailer's structure (like the coupler) is capable of handling the increased load.

expert reply by: Mike L