There are six important factors to look at in order to identify a leaf spring:

1. Taper/Parabolic or Multi-leaf Spring - In other words, are all the leaves the same length, thick in the middle, tapering out towards the end, or is it many leaves, all the same thickness, cut shorter as they get lower in the pack?
2. Main Leaf Length - This is the distance from the bolt in the center of the spring to the center of the eye in both directions. Be sure to measure along the curve of the spring for an accurate measurement. In some cases, a spring may not have eyes. In this situation, measure the length of the longest leaf in each direction of the center bolt, or to the inside of the hooks from the center bolt, as applicable.
3. Spring Width - More specifically, this is the width of the spring at the center bolt.
4. Pack Thickness - This is the thickness of the spring down its side at the center bolt.
5. Spring Arch - The best way to think of this measurement is to imagine a line that extends from one eye to the other. The spring arch distance would be the distance from the center bolt (including the center bolt) to that line.
6. Number of Leaves in the Spring Assembly - see the heading Spring Assemblies with Multiple Stages below for a more detailed explanation.

Spring Assemblies With Multiple Stages

Many leaf springs are made using leaves with different specifications from each other. Groupings of leaves with different specifications are referred to as stages.

As illustrated below, a spring may be made of 6 leaves, with 1 leaf at the bottom of the assembly which has different measurements and a different arc than the other 5 leaves. We would use the notation “5/1” identify this as a 6-leaf spring split into two stages: 5 leaves in the first stage, and 1 in the second.