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Many people only realize an issue when ordering replacement leaf springs: measurement proves to be more crucial than they initially thought.
Even a 5-millimeter error could prevent proper installation.
Our technicians have found that the most common mistake in actual communication is not failing to measure dimensions, but measuring the wrong location.
frequently asked questions
The measurement refers to the outer edge of the spring eye, not the center.
Measuring the arc height under load conditions
Ignore the leaf spring bushings
Count one fewer tablet
These errors will result in mismatched leaf spring parts.
prepare
Steel tape measure
vernier calipers
Ruler or level tool
Paper and pen
Mobile phone or other video recording device(take photos while recording measurements for easier communication later)
Eye-to-Eye Length
This is the most critical data, referring to the straight-line distance between the “center points” of the two spring eyes.
It’s not the outer edge.
It is not the arc length.
It is center-to-center.
During measurement, align the 0 mark of the tape measure with the center of the anterior eye and extend it to the center of the posterior eye. Multiple measurements are recommended to ensure consistent readings.
Spring Width
The width affects both the load-bearing capacity and the compatibility of the mounting base.
Use a vernier caliper to measure in the middle section of the main piece; avoid measuring at the transition areas at the ends.
Number of Leaves & Thickness
Count each piece carefully.
The main sheet is the longest, while the auxiliary sheets gradually shorten; do not omit any half-sheet or supplementary sheet.
The recommended thickness of the main plate should be measured near the center hole, and the total thickness must also be recorded as it affects the length of the U-bolts.
There are designs with thicker middle sections and thinner ends, as well as those featuring a gradual thickness transition——these variations should not be overlooked.
Arch Height
The arch height determines the vehicle’s overall height.
Place the springs flat on a horizontal surface, ensuring the bottoms of both spring eyes contact the ground.
Connect both ends with a ruler and measure vertically from the highest point at the center to the reference line.
Spring Eye Inner Diameter
If an old bushing is present, first confirm whether the measurement is for the metal hole or the inner diameter of the bushing.
Measure the inner diameter with a caliper, preferably from multiple directions.
Note that the dimensions of the anterior and posterior eyes may sometimes differ and should be recorded separately.
Center Bolt Position
Find the leaf spring center bolt and measure the distance from the center of the front eye to the center of the bolt.
Some designs are asymmetrical; do not assume the hole must be exactly in the center.
Some experiential insights
Many customers overlook certain details during measurements: if the leaf spring is severely deformed, the arc height measurement may no longer reflect the original specifications. When old components are heavily worn, the center hole measurement may also be inaccurate.
If the original document is deformed, it is best to verify the information by referring to the drawings, vehicle specifications, or original manufacturer data.
Final recommendation
The measurement isn’t complicated, but it requires patience.
For each measurement, take a photo immediately and clearly capture the tape measure reading—the crisp, reliable image will save you considerable time.
Don’t rush to place an order—first verify that the data is complete and accurate. From standard trailer leaf spring replacement parts to heavy-duty leaf springs, precise dimensions are the first step.
If there are any uncertainties during the measurement process, please feel free to contact us at any time or send us the sample directly. We will provide you with a comprehensive solution.