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Trailer Leaf Spring Guide

time2022/04/28

Trailer springs are an important part of suspension but are often forgotten until something goes wrong.

Trailer Leaf Spring Guide
Trailer springs are an important part of suspension but are often forgotten until something goes wrong. Leaf springs or coils, these trailer accessories are easier to replace when you're not heavily loaded on the highway, so it's important to recognize when they're worn out.


There is a wide range of springs for different conditions and loads:

Eye-to-eye (shackle) spring

Traditional leaf springs, their ends are coiled in an "eye" in which a bush is placed. The front of the spring is held in a "hanger" while the rear swings on shackle bolts and plates around the rear hanger.

They are common in multi-axle configurations because when one bearing carries more weight (such as across a curb), the load can be shifted for more even distribution.

Slipper spring

Simple and long to wear, the slipper spring has an eye on one end, while the leaf that opens on the other end forms a "tail" that slides in a hanger welded to the trailer's chassis. They are a low-cost solution to multi-axle trailer suspensions because they can be attached in sequence or as a separate kit, but they do not transfer loads between axles.

Parabolic spring

This spring is slippered style, with only one leaf, thicker in the middle and tapering at the end. They work the same way as multi-leaf springs but are great for boat trailers because they don't trust easily.

Tandem rocker spring.

Eye-to-eye springs are most commonly used in this configuration on multi-axle trailers. Connecting the springs through a rocker arm assembly allows for load transfer when one wheel carries most of the weight (such as across curbs), allowing for a more even distribution of the load.

Rocker roller springs are a variant of the standard rocker suspension, offering progressive spring rates and a very comfortable ride.

They are suitable for wagons, caravans, livestock, and other trailers and have a more forgiving ride than standard suspension systems.

Coil spring

Coil springs are becoming a common type of trailer spring, especially for road use, but they require shock absorbers to reduce vibration on bumpy roads. (Leaf springs do this inherently through the friction of the blades).

When should they be replaced?

Whenever you see cracks in the springs, it's time to replace them. Also, if you can see too much rust between the leaves, that usually means they are less flexible and at risk of breaking.

Some surface rust is to be expected, but if the rust is severe or starts to come off in large pieces, it will affect the strength and load-carrying capacity of the spring.

When it's time to replace a spring, you need to know:

1. The type and size of spring suitable for the trailer.

2. The full load weight you expect the spring set to support

3. Hanger kit for springs.

4. U-bolt kit to match spring and axle configuration.

Check the condition of your trailer springs at least once a year, or before taking them out for operation after a long break. They're fairly cheap and easy to replace as a whole, so don't try to keep using a worn-out system. 

If you need to replace the trailer leaf spring or buy it, please contact us.

Haway is a professional custom trailer axle and parts supplier. We have been dedicated to manufacturing and supplying trailer parts. Our products are exported to Australia, New Zealand, Canada, the United States, and some European countries. Our factory produces a large number of trailer leaf springs, trailer axles, torsion axles, trailer fenders, trailer jacks, and boat trailer parts. Offering a wide range of trailer parts, Haway has one of the most complete lines of trailer parts.