By Nelson D. Beverly
Have you ever seen someone towing a huge boat with a little SUV? The front wheels are barely touching the ground! Or a pickup truck loaded with a pile of stuff that is twice as high as the truck itself?
My dad always says, “They are putting two ton of fertilizer in a one-ton truck,” meaning their load is way more than the vehicle can handle.
Unfortunately, this type of situation occurs all too frequently and people don’t realize the safety hazard they are creating. An overloaded vehicle can’t stop or take evasive maneuverers very well. Plus the longevity of the vehicle is shortened by putting stress on vehicle components beyond what they were designed to handle.
Haul vs. Tow
So how much load can your vehicle handle? First, you have to understand two terms: haul and tow.
Hauling is the stuff you put in your vehicle, like people, fuel, cargo, etc. Towing is when you are pulling something behind the vehicle, like a boat, yard trailer, camper, etc.
GVWR and GCWR
So a better question is: “How much can I haul and how much can I tow?” To answer this question, you will have to understand two acronyms, GVWR and GCWR.
The gross vehicle weight rating (GVWR) tells you how much you can haul. It takes into account the weight of the body, chassis, engine, fluids, fuel, accessories, people, and cargo. It doesn’t account for the weight of a trailer though. The gross vehicle weight (GVW) will vary constantly, but at no point should it ever exceed the GVWR.
The gross combined weight rating (GCWR) tells you how much you can tow. It takes into account the aforementioned GVWR, but also includes the weight of any trailers. The difference between the GCWR and the GVWR is the amount of weight that can be towed.
Some manufacturers make it easy and include a towing capacity rating that clearly defines how much weight your vehicle can tow with no math required! You can find all this information in your owner’s manual or online at the manufacturer’s website.
Before you install a new trailer hitch, you have to determine what class you need. Gross trailer weight is the maximum amount of weight the trailer can carry (including the weight of the trailer itself). The tongue weight is the amount of weight the trailer adds to the tow vehicle. There are four major classes of trailer hitches:
CLASS NAME GROSS TRAILER WEIGHT TONGUE WEIGHT
Class I 2,000 lbs. 200 lbs.
Class II 3,500 lbs. 350 lbs.
Class III 5,000 lbs. 500 lbs.
Class IV 12,000 lbs. 1,200 lbs.
Modern-day vehicles are designed with many computers that control almost every aspect of vehicle operation, including the exterior lighting system (brakes, headlights, etc.)
For example, a computer monitors the voltage of the exterior lights and if it deems there is an excessive load, it will shut down the appropriate circuit. The old method used a fuse that would trip if a load became excessive.
So when new trailer wiring connections are installed, the appropriate computer has to be “told” about the new load so it doesn’t inadvertently shut down circuits or set fault codes thinking there is a problem.
Be smart about what you haul or tow, know your limits, and stay within them.