Don't have to tell you off-roaders that to survive the rigors of off-road driving, trucks and Jeeps need to be tough. This could very well include having axles that are built to withstand the heavy strain of off-roading. Besides thinking about equipment like shocks, tires, and bumpers, truck owners should know about the different types of axles that are available. Axle type may be important when either choosing a vehicle for off-roading or upgrading if looking to push that prized truck or Jeep to the extreme.
Truck Axles - Semi-Floating and Full-Floating
Truck axles come in two versions, semi-floating and full-floating. Every light duty truck or SUV has full-floating front axles. The rears may be one or the other depending on vehicle size and weight as well as the amount of weight and strain the truck is built to withstand. Considering that the purpose of all axles is to both carry vehicle weight and transfer power from the differential to the wheel, these two types will do the same thing but in different ways:
----- Semi-floating - A semi-floating axle is the more common rear axle used in 4WD trucks and SUVs under ¾ ton. It is designed so the wheel is mounted directly to the flange on the end of the axle shaft. In this setup, there is a single bearing that serves two purposes: support the vehicle weight and turn the wheel. This is done by transferring energy received from the engine through the transmission and differential. It is a lighter axle, suitable for most purposes on lighter trucks, with a GAWR up to 4500 lbs.
----- Full-floating - A full-floating axle is the heavier axle, usually only included on heavier duty ¾ ton trucks and heavier trucks on up. It is designed so the wheel is mounted to a hub that turns on a dual-spindle roller bearing mounted onto the main-turning bearing. With this design, weight is carried by the hub and roller bearings while the axle bearing is responsible only for turning the wheel using force from the drivetrain. Full-floating axles have over twice the bearing area as semi-floating axles and can carry more weight per axle up to 10,000 pounds.
Which Is Better for Off-Roading?
Full-floating axles are able to bear much greater loads than semi-floating axles, making them preferable in other extreme circumstances as well. Off-roading, although it may not involve carrying or pulling heavy loads, puts the same type of strain on suspension and drivetrain parts. In these conditions, a full-floating rear axle is more durable and better able to withstand greater loads because load bearing and wheel propulsion are handled by different bearings.
Full-floating axles also offer the convenience of being able to remove a broken axle shaft, something that could definitely make repairs to a truck used for off-roading easier by leaving a functional wheel still mounted to the hub.
For anything beyond the basics, it’s best that even lighter-duty trucks used for off-roading have full-floating rear axles. Since many people start with whatever truck they can afford, replacing semi-floating axles with full-floaters is an improvement that can be added to the upgrade list along with all the other performance parts like bumpers to be installed. Breaking an axle is never expected, so preparing a truck with more durable full-floating axles is the best suggestion for anyone looking to do more than simple trail riding!