What Does Trailer GVWR Mean for Maximum Cargo Weight Capacity and Can it Be Increased

Question:

I realize we cant be exact until everything is actually weighed on a set of scales. With that in mind, Im looking at 6x12 enclosed trailers with tandem 3500# axles total of 7000# worth of axle rating. How does this rating figure into a calculation of the GVWR? Other than the manufacturers sticker, can I calculate an approximate GVWR? Or how do I calculate how much above the weight of the trailer itself I can safely load in the trailer? I also realize that tire size/rating can play into the equation as well as restrictions related to the size hitch Bottom line, how do I come up with how much I can safely carry in a trailer with tandem 3500# tandem axles?

asked by: Larry M

Expert Reply:

When a manufacturer indicates a trailer's GVWR, which is the most it can ever weigh under any circumstances, this consists of the weight of the empty trailer itself plus the maximum cargo weight you can put in it. Under no circumstances do you want the loaded trailer to weigh more than the manufacturer's rated GVWR.

Sometimes trailer makers may install axles whose combined rating is not exactly the same as the specified GVWR. The total axle capacity could be more than or slightly less than the GVWR. Some trailer manufacturers may indicate a separate maximum payload capacity to help owners avoid overloading. Payload capacity is simply the trailer GVWR minus the actual weight of the trailer itself.

The manufacturer's engineers determine the GVWR based on all of the components used to build the trailer, including the frame, the axles, the hubs, the suspension parts and the wheels and tires.

Just as a hypothetical example, if you could know that your trailer's "weakest link" in terms of weight capacity were its tires, you could increase the trailer's capacity by installing higher-rated tires, such as Load Range D tire # AM10210 (good for 1650-lbs each) in place of Load Range B tires # AM1ST74 (good for 1100-lbs each). The problem is that unless you are the mechanical engineer that designed the trailer this is virtually impossible to figure out.

So, staying within the specified GVWR is really the only safe way to use any trailer.

expert reply by: Adam R