Overloaded 7000 Axles on HR Aluma Scape 31 5th Wheel Trailer

Question:

The GVW for my 5th wheel is 14,4000# s. The axle and bearing weight is 14,000 #s, how long would it take to wear the bearings out with this overload condition? I have a HR Aluma Scape 31. Dexter axles with 031-071-03 bearings, the specs that I see rate the bearings etc: at 3,500# per bearing. When I took the brake drum off I found pieces of metal laying in the bottom of the brake drum bearing area, the second wheel on the same side has the same problem. I have not weighed the rig to find out what weight I am hauling. That will be the first thing I do before I take off this next spring and summer. Any suggestions on finding a way to add over the 14,400#s.

asked by: Russell A

Expert Reply:

If your axles are indeed rated for 7,000 pounds each, and your actual trailer weight is at 14,400 lbs you are already overloading each axle by 200 lbs. Determining the actual fully loaded and ready to tow weight of your fifth wheel is very important.

Although some would argue that there would be some sort of cushion or wiggle room engineered into the axles, in my opinion you will need to lower the trailer weight to the point where it is below the axle capacity or upgrade to larger capacity axles and springs.

The Dexter # 31-71-3 50mm bearings are also used on an 8000 lb axle, which means that the bearings themselves would have at least a 4000 lb capacity. When axles are constructed, they are typically arched a bit. When weight is applied to them, they will straighten out. This provides for even tire contact with the ground as shown in the diagram I have attached. When the axle tube is overloaded, it can dip, causing unnecessary stress on the hubs, bearings, spindles, wheels and tires. Even though your bearings might be within capacity, the fact that the axle is overburdened will place stress on them that they are not designed to handle.

There are too many variables for me to say how long a set of bearings would last.

Upgrading to 8000 lb axles would be my recommendation.

expert reply by: Mike L