Is The etrailer 4-Leaf Slipper Spring e24SR Measured Under Load?

Updated 05/19/2026 | Published 05/16/2026

Question:

1. Are the lengths of these leaf springs measured with no load? 2. Where are the length measurements taken? From ends of the spring eyes or from bolt center to bolt center?

asked by: Geoffrey M

Expert Reply:

Hi Geoffrey!

The length of the etrailer 4-Leaf Slipper Spring w/ Open Eye End for 4,300-lb Trailer Axles - 26-1/4" Long # e24SR is indeed taken when there is no load on it. When you measure your springs, you will also want to be under no load at all (we typically say it's best to jack up the trailer by the frame when measuring the leaf springs).

As to your question about how this is measured, it is from center eye to center eye (or at least where the center of the eye would be on a slipper spring. If you check out the included image, I do have the corresponding measurements listed below:

A: 13-1/8"
B: 27"
C: 26-1/4"
D: 13-3/4"
E: 14-1/8"
F: 3-1/2"

What are you wanting to install these on? And what are you typically hauling?

expert reply by: Lazer S

etrailer 4-Leaf Slipper Spring e24SR
(click to enlarge)

Geoffrey M.

5/18/2026

Thank you so much for a thorough answer to my questions. This is for a boat trailer with an estimated MGVW of 3500 lbs. The springs I have now are about 30 years old. My old trailer fell apart literally due to excessive rust and corrosion. I bought a good used trailer that didn’t have brakes so I swapped axles with the springs and the brakes. The new trailer sits too low and it looks like the springs from the old trailer are nearly straight with very little curvature so I’m considering new springs. I might also need longer spring mounts but I’m not sure I can do that without a lot of metal fabrication and welding. I’d like to raise the trailer at least three inches. Again, thank you for your time and answers. Very helpful!

Lazer S.

5/19/2026

@GeoffreyM When springs flatten out, they definitely need to be replaced. That will help give you a little more lift, but there are a couple ways to get more without resorting to new hangers. First would be the Dexter Trailer Springs Over-Under Conversion Kit # K71-384-00. This moves you axle underneath the leaf springs if it isn't already. It would gain you the diameter of the axle in height (2-3/8"). Second would be the Correct Track Trailer Alignment and Lift Kit - Tandem Axle # RR23QX. This says it's for a tandem axle, but to get the 2-1/4" of lift, you will need to have these on all 4 hangers. It's a bit expensive, but it does work. New springs and one of these should get you at least 3". If not, you will need to look into new hangers.

Geoffrey M.

5/19/2026

@LazerS..Again, thank you for your expertise. It looks like over-under conversion with new springs is the way to go. My axle has a square cross-section instead of round. The u-bolts in the picture are for round axles. But I can get square u-bolts from McMaster-Carr so that won’t be a problem. Thanks again!!