Increasing Load CapacityI have a 2009 Chevrolet 2500 Duramax crew cab short box truck. The truck is rated to haul 13,000 pounds with a bumper hitch and 13,900 pounds with a fifth-wheel hitch. The same-year 3500 truck is rated for 15,400 pounds with a fifth-wheel hitch. A 2016 Chevrolet 2500 truck is rated also at 13,000 pounds with a bumper hitch and 13,900 with a fifth-wheel, while a 2016 3500 is rated at 17,200 pounds. I am quoting numbers for single-tire rear axles only. Can my 2009 be increased to the 17,000-pound rating?
Legally, no. The load ratings of a truck are established and set by the vehicle manufacturer, so regardless of what changes you make to increase load-carrying capacity, the numbers on the doorsill tag are not going to change and are the only thing that officials are going to consider. Why is this important? While it is pretty unlikely that you will ever be inspected while hauling noncommercially (unlikely but not impossible), it can become a very big deal in the event of an accident. Should you ever find the front of your truck stuffed into a bus full of nuns, if it’s determined that you were hauling weight beyond the ratings set by the factory, you open yourself up to all kinds of liability whether or not the accident was your fault. But aside from litigation, the load capacities of trucks are established primarily for safety, so exceeding those numbers really isn’t a good idea anyway.
As your research indicates, the weight ratings for the same vehicle model can vary from year to year, and often even from vehicle to vehicle within the same model and year. This is because vehicle options and equipment, such as axle size and ratio, brakes, transmissions, engines, and suspension, have an impact on GVWR. For example, a truck that’s identical to yours may have a lower GVWR simply because it has a higher (numerically lower) rear axle ratio. Many manufacturers and especially Chevrolet often use different rear axles in the same model truck, sometimes because of engine options (gas versus diesel) but also for lighter or heavier load ratings within the same truck model. While it’s technically possible to swap all the components that would make your 3/4-ton truck a heavier-rated 1-ton, it’s not going to matter from a legal standpoint. If you are hauling at or beyond the capacity of your truck, the only solution is a different truck with a heavier rating.