How to Select Correct Replacement Trailer Leaf Springs

Updated 11/25/2016 | Published 11/24/2016

Question:

98 Sunnybrook M-30FBS, GVWR 8600 lbs. 2 axles @ 3inch dia., 4 leaf springs, 26+/- fixed hanger to equalizer shackle under load. Im assuming your e44SR is the correct replacement, any thoughts?

asked by: Eric R

Expert Reply:

The best way to measure a trailer spring for purposes of selecting a replacement is to remove it completely from the suspension. It is also important to note that leaf springs will tend to elongate over time as they wear. You might pull a well-worn spring from your trailer and find its eye-to-eye length is actually 1/2-inch to 3/4-inch longer than when it was new (and also longer than the correct replacement).

For instance, part # e44SR that you referenced is a 4-leaf double-eye spring 25-1/4-inches long that is rated for use with 5K axles. Your axles should have a plate or sticker that tells you their weight rating, which is likely to be 5000- or 5200-lbs based on the trailer's GVWR. Based on the age of your trailer it is quite likely that these are in fact the correct springs to use as replacements. Always replace leaf springs in pairs to ensure the trailer tracks correctly and to avoid uneven tire wear.

expert reply by: Adam R