How to Measure to Select Correct Replacement Leaf Springs for Utility Trailer

Updated 11/01/2017 | Published 10/31/2017

Question:

I need replacement leaf springs for a utility trailer I purchased. The current springs I believe are incorrect as the shackle is angled forward and the axel itself is not centered within the wheel well. My measurement from spring hanger to hanger is 25 1/4”. Axel is a 3,500lb unit. Looking to use a heavier duty axel as I’ll be mounting a large smoker on the trailer.

asked by: Landy B

Expert Reply:

The best way to measure your springs is to remove one from the suspension so it is no longer under tension. This way you can accurately measure its eye-to-eye length. If your hangers are 25-1/4-inches apart chances are that your spring would be 23-1/8-inches, such as # e59SR which is indeed rated for 3500-lb axles.

Keep in mind that swapping out trailer leaf springs or the axle may not actually increase the capacity of your trailer. This would be the case only if you knew for certain that the suspension was the trailer's weakest link. The frame or deck surface may not be rated as high as the axle, or vice versa, so do not assume your trailer can handle more weight just because you install a higher-capacity axle.

You will want to check your hangers to ensure they are not damaged or bent, since you mentioned the axle is not centered in the wheel wells. That problem could be from damaged hangers or springs, or from an axle that has been bent from an impact.

expert reply by: Adam R