Comparing Tow Rating of Towing Vehicle to GVWR of the Trailer Being Towed

Updated 01/27/2014 | Published 01/25/2014

Question:

Im in search of a new travel trailer for use in Pennsylvania and a few of the surrounding states. Travel trailers have a published dry weight and then an additional weight carrying capacity for additional loads such as dry goods, supply and waste water tank liquids, etc. Together these two numbers combine to give the GVWR for the trailer. Up until now, Ive understood that my trucks towing rating had to be at least as high as the GVWR of the trailer, even if I dont have the trailer fully loaded to the GVWR value. I now have a trailer salesman trying to convince me that I only need to be concerned that my actual loaded weight is less than the tow rating value for the truck Im towing with. Im confused now... Which number do I need to compare to my vehicles published tow rating value? Is it the actual weight of my trailer plus its contents or the GVWR of the trailer? I want to make sure Im legal and Im having a very difficult time finding any of this in writing for PA or for any other state for that matter. Can you answer this question for me and point me to some reference material where I can read more on this for PA and for other states? Thanks in advance for any help you can provide.

asked by: Todd S

Expert Reply:

From a capacity point of view the truck and hitch only need to be rated high enough for the weight of the trailer when it is loaded and ready to tow. This is always going to be higher than the dry weight of the trailer because it is empty. If the gross trailer weight and tongue weight when loaded and ready to tow are below the capacity of the truck and hitch then you are safe.

There is also something called gross combined weight rating. This is the most that both the truck and trailer can weigh when loaded with cargo, passengers, fuel, basically everything. You will want to stay under the GCWR as indicated in the truck owners manual or sticker in the drivers side door jamb.

For example if a truck has a GCWR of 15,000 pounds you would take the dry weight of the trailer, lets say 5,000 pounds, and subtract it from the 15k. That leaves 10K. So then lets say the truck curb weight is 6,000 pounds. Subtract that from the 10K and you are left with 4,000 pounds. So then you load the truck with cargo, passengers, and fuel, say another 1,500 pounds. Subtract from the 4K to get 2,500 pounds. Then you load some more stuff, water, fuel, on the trailer, another 1,000 pounds. This takes its down to 1,000 pounds. So the gross combined weight of the truck and trailer is 14,000 pounds in this scenario, which is below the 15K capacity.

Of course your set up will have different weights and capacities but that is how GCWR works.

To find out the laws in your state (Pennsy has some of the toughest in the country) I recommend visiting a local department of motor vehicles, license bureau, and/or state patrol. You would think that a sales person in your state would be up on the law. Whether or not they are or if they are trying just to make a sale is something you will be able to determine once you have contacted the agencies mentioned above.

expert reply by: Michael H