If you have spring axle suspension your trailer will have leaf springs. Your suspension should look similar to this:

If you have torsion axle suspension your trailer will look similar to this:

Both torsion and suspensions have a record of reliability. There are advantages and disadvantages to both, but it comes down to your preference because they both work great in their own way.

Torsion axles are made up of thick rubber cords concealed in the axle’s tubing. As each wheel moves up and down, the rubber cords compress offering an even wheel suspension for a smooth ride. Each wheel acts independently, moving and absorbing shocks. Torsion axles are mounted directly to the frame which means fewer moving parts compared to spring suspensions, resulting in a smoother shock action. This stiffens the frame, reducing flex.

This system is also less likely to corrode because the axle tube is galvanized inside and out. There are no metal-to-metal action like springs, so bare metal isn’t exposed, preventing corrosion. There are fewer working parts in a torsion suspension, therefore less maintenance is required.

The disadvantages of torsion are they are more expensive than spring suspensions and more expensive to repair or replace. There is also no impact distribution, so if you hit a curb, the full impact is on one wheel or set of wheels.

Leaf springs have been used for centuries and have proven to be solid performers. This is the most widely used suspension system due to its affordability. Spring suspensions are the most dependable for even tire wear and a steady ride, especially in multi-axle applications. Leaf springs better absorb the load from uneven ground or shock from a pothole. Each tire has its own set of springs. If you have to store your trailer on uneven ground, the independent wheel suspension means the trailer will hold up better over time. Spring suspensions are cheaper and easier to repair compared to torsion suspensions.

One con of springs is the metal-on-metal design can lead to faster wear, leading to more frequent repairs. Spring suspensions also tend to be a bouncy ride with an empty load or on uneven, rough roads.