Not tool but you guys are smart

The heavy duty (my definition of heavy duty anyway) have what is called a �full-floating� rear axle. This type of axle is the industry standard for all trucks including the 18-wheelers. In this configuration there are two heavy large bearings between the outside of the axle housing and the hub where the wheels bolt to. The axle bolts to the hub through a flange on the outside of the hub and the other end is carried by the spider gear in the differential.

Now when pulling something there is a certain amount of weight that is transferred to the rear of the tow vehicle. In the semi-floating axle, the axle shaft actually has to carry all the weight of the vehicle plus deliver the rotational torque to keep the vehicle rolling down the highway. To compound this, as the shaft rotates the weight stress changes direction on the shaft and if the load is heavy enough the axle shaft may actually �flex� as it rotates. The spider gears get additional stress on them as well. This is a recipe for a broken axle.

In contrast, the full floating axle transfers all the weight force to the two large bearings to the hub. The axle housing carries the weight stress; the only stress the axle carries is the rotational stress. I much prefer the full-floating axle configuration when pulling or hauling.

The difference between the empty weight of your vehicle and the gross weight is the maximum weight you should possibly put on your vehicle. This includes people and gear.

The maximum tow weight (not tongue weight) is available from your manufacturer. Unfortunately you are likely to run into trailer salesmen who will say something like "Oh yeah, you can tow this with your truck. Sure. Easy." It ain't necessarily true.

If you are serious you need to spend some time on the Open Roads Forums or other such. A link is included below.

All that said, we much prefer fifthwheels. We have a 30' Sunnybrook, which we tow with a 3/4 ton diesel pickup (Dodge Cummins).

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