Trailer axles are normally divided into two different types: Spring axles and torsion axles. While these two types of axles perform the same basic job, the way they go about suspending and cushioning the trailer load is completely different.
Spring Trailer Axles
This type of trailer axle will be immediately recognizable to nearly anybody who has been around motor vehicles for any length of time. Much like the name suggests, spring axles are constructed of stacked flat spring stock in proportion to the load.
But rather than having the spring over the axle (like on a pickup truck), trailers normally have the axle