All You Need To Know About Trailer Suspension & Axles

You will frequently choose to replace your old or worn-out trailer parts with like-for-like replacements when it comes to the axle or suspension of your trailer. However, there are occasions when it is preferable to swap out your axle or suspension unit with something better suited to the use of your trailer. To get the maximum performance out of your trailer, make sure the axle and, in particular, the suspension are adequate for the operation of the trailer. A trailer axle and suspension system have to be durable and dependable.

Leaf springs

One of the first types of suspension, leaf springs, was initially invented in 1804 by a British engineer named Obadiah Elliott. Of course, since the traditional leaf spring, things have evolved a little, but the basic idea hasn't changed. Therefore, you might believe that using this 200-year-old device on your brand-new trailer needs to be updated. They are, nevertheless, still among the most widely used trailer suspension systems available today for a good reason: they are, in essence, everything a trailer suspension system should be! One of the least expensive forms of suspension, they can support big loads while dispersing stresses and strains that may otherwise harm the trailer or axle. They are also simple to maintain, repair, and replace.

The versatility of leaf springs to support virtually any trailer weight is one of its best qualities. The smallest trailers employ single-leaf springs, whereas the largest trailers use huge 12+ leaf springs. No matter how big or little they are, the springs all function in the same straightforward manner. The only thing that counts is using the proper leaf spring for the intended trailer application. A spring with a low load rating will ultimately bottom out, whereas a spring with a high load rating will be too rigid and unable to absorb any vibration or bumps.

Since leaf springs are intended to glide over one another when in use, they will ultimately deteriorate and require replacement. This implies that the durability of your leaf spring depends on its construction and finish. The most common alternatives are painted or galvanized springs, with painted springs being the more durable of the two. A somewhat weaker spring that loses camber more quickly than its painted counterpart might occasionally result from the heating and manufacturing processes used to create galvanized leaf springs.

Slipper Leaf Springs

One of the most basic types of leaf springs is the slipper leaf spring. The springtail, as its name implies, is a sliding component of this spring. Where it grinds against the slipper, the leaf spring of a slipper might be more prone to wear in this location. On rocky terrain, the classic slipper leaf spring is infamous for being extremely loud. To address this problem, anti-rattle slipper leaf springs are offered.

Slipper leaf springs are perfect for trailers with two or more axles because they offer excellent lateral stability. These springs are also quite small, which makes them ideal for trailers with modest deck heights when combined with a single axle.

Double Eye Leaf Springs

Comparing the double-eye leaf spring to the slipper leaf spring, an additional loading point is added to the chassis. The double-eye leaf spring's three loading points serve to evenly distribute the weight of the trailer and reduce the strain on the axle and chassis. To fully enjoy the benefits of this type of spring, it must be fitted and configured properly. Improperly mounted springs may seize if the trailer is loaded too heavily or driven over very rough terrain.

The lateral stability of slipper leaf springs is required for usage in multi-axle configurations, although these springs are excellent for single-axle trailers. They are slightly on the big side due to their increased complexity, which restricts how low your trailer deck height may be.

Parabolic Springs

The parabolic spring, a contemporary variation on the leaf spring, often consists of just one leaf that is thicker in the middle and gets thinner as it gets closer to the ends. The interleaf friction that leads to wear on other types of leaf springs is eliminated by this spring. Due to a decrease in stiffness, this type of spring often weighs less than a typical leaf spring and provides a smoother ride. The maximum loading capacity of the spring is reduced as a result of the change in stiffness. Multi-layer parabolic springs with spacers between each leaf can be used to address this, but they naturally add weight to the spring.

The parabolic spring, while having only one leaf, can take up a lot of space beneath the trailer, which reduces the minimum deck height. This problem is even worse if many layers of springs are utilized.

Torsion Suspension

Due to its reduced susceptibility to rust damage, torsion suspension is preferred for use in boat trailers. They are made out of a torsion arm, or swing arm-style axle, that spins inside a rubber cage. The torsion arm converts the oscillation motion of the axle into a rotational motion, which is subsequently dissipated by the rubber in the enclosure via the suspension system. The swing arm then returns to its initial position due to the rubber's flexibility.

Due to its total independence from each trailer tire, this form of suspension may offer an extremely smooth ride. The trailer may have a very low deck height thanks to the low profile of the torsion modules. The comparatively low loading capacity of torsion suspension, which is regulated at about 2500 kg on a tandem trailer, is one of its primary drawbacks.

A significant increase in stresses on the trailer chassis results from the absence of axle sharing. When compared to other forms of trailer suspension, this can be so drastic that it can lower the carrying capacity of a chassis by up to 25%.

In summary

Contrary to what you would believe, the axle and suspension you use on your trailer can significantly affect how well it performs. This is why it's crucial to try to match your trailer's suspension and axle setup as closely as you can to the purpose for which it's being used by the trailer suspension supplier.