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In fact, many people only realize they don’t know what size leaf springs they need when they need to replace their vehicle’s suspension system.
It may seem like just a matter of size, but in reality it involves multiple factors such as length, width, curvature, and load capacity.
It is crucial to note that selecting the wrong specifications for either truck or trailer leaf springs can directly impact installation quality and safety.
First, confirm the requirements
Before measuring, clarify your requirements: do you need original factory parts or consider upgrading to replacement parts?
Different applications require different selection approaches. If you’re simply replacing old components, simply identify the original vehicle specifications and choose replacement leaf springs accordingly.
If the vehicle is frequently overloaded or if the existing leaf springs show significant collapse, upgrading to heavy-duty leaf springs may be advisable.
While it is theoretically possible to measure certain dimensions on the vehicle, curvature measurement errors can be significant. For accurate alignment, it’s best to disassemble the component first before measuring.
Eye-to-Eye Length
Generally speaking, this is the most critical dimension, as it directly determines whether proper installation is possible.
The term “eye-to-eye length” refers to the straight-line distance between the center points of two spring eyes. It is important to note that this measurement should be taken from “center to center,” not from outer edge to outer edge.
To measure, first remove the leaf spring, locate the geometric centers of both spring eyes, and use a steel tape measure to take the measurement.
Even a length error of just a few millimeters can prevent installation.
Many users encounter errors here, particularly when measuring with the older version of Spring, where measurements may easily deviate. It is advisable to maintain a practice of taking photographs during measurement for subsequent communication purposes.
Spring Width
Width determines whether it matches the mounting base and U-blot positions.
The width is incorrect; it cannot be installed.
Use a vernier caliper for measurement.
Arch Height
The curvature affects the vehicle’s height.
Place the spring flat on the ground, establish reference lines at both ends, and measure the vertical distance from the highest point in the middle.
If the old leaf springs have collapsed, the reference becomes inaccurate; please verify the original manufacturer’s specifications.
The most common sign of faulty leaf springs is reduced curvature.
Thickness
Generally, the number of leaves determines the load-bearing capacity.
The drawings for multi-plate leaf springs are designed with varying thicknesses and numbers of plates based on actual load requirements.
If the unit is frequently operated at full load, consider increasing the number of blades or using thicker specifications; however, it will become stiffer when running unloaded after modification.
custom made
If the vehicle model is too niche or has stringent load-bearing requirements, standard components commonly available on the market may not be sufficient.
At this point, custom leaf springs are the ideal solution. A professional spring manufacturer can create customized drawings tailored to your vehicle’s model and load capacity, using higher-grade steel, increasing the number of plates, or adjusting the curvature as required.
Common Misconceptions
1.Measures length only, not width.
2.Ignore the presence of leaf spring bushings.
3.Do not blindly add blades upon observing minor collapse.
Identical dimensions do not guarantee the same rated load capacity. When conditions are limited, first verify the eye-to-eye length, spring width, and required load capacity, then coordinate with the vehicle manufacturer based on available specifications.
When taking measurements, it’s best to snap a photo or record a video—it’ll save you a lot of time during follow-up communication.
Choosing the correct specification prevents frequent replacements. If unsure about the size, record all verifiable details before purchasing—avoid relying solely on experience.
The leaf spring features a simple structure yet plays a critical role in ensuring driving safety. If you have any questions during the procurement process, please feel free to contact us.