TRI DRIVE

I know a few guys running this type of configuration in the US today. If you see a truck like this that operator is very serious about their oversize freight.

Tri drive is meant to help take some of the abuse out of extremely heavy loads by splitting up the torque, and weight between all three rear ends. This is not to be confused with a lift axle which has only a single wheel on that axle not duals or a drive. You would be surprised how many trucks on the road only have one drive axle and not two. They have two in appearance but only one actually drives.

One problem associated with running the tri-drive is they don't turn so well when heavily loaded, the truck just wants to go straight.

On a tractor that has a lift axle instead of the tri- drive they blow the air bags on that axle to unload it, then it is easier maneuver. Tri drive trucks also have a way to blow the bags on that first axle to make them turn better too when loaded or empty. It is really hard on tires, and suspension dragging them as the truck turns.