It shouldn’t come as a surprise to learn that weight has a big, big impact on your ability to tow things with your vehicle. But once you dig into the topic of trailers and towing, you may be surprised at how many different weight ratings and specs are factored into the towing equation.
From horses to hot rods, boats to bath tubs, it’s important to know how the weight (and its distribution) of whatever you’re hauling will affect the tow vehicle. So we’ve put together this quick breakdown of the various weight ratings you’ll need to know before hooking up your trailer.
Gross Vehicle Weight Rating (GVWR)
This is the amount of TOTAL weight your vehicle can carry, including the weight of the vehicle, its cargo, passengers, fuel, and something called “tongue weight” which we’ll get to here in a sec. The GVWR number will be unique to your vehicle’s specific year, make, and model.
Gross Axle Weight Rating (GAWR)
Gross Combined Weight Rating (GCWR)
This is the maximum safe weight of the vehicle, passengers, gear, and trailer.
Gross Trailer Weight
This is the weight of the trailer AND the weight of your cargo—be it a boat, livestock, grand piano, or whatever. That also includes any fuel jugs, spare tires, tie downs, or anything else you toss into your trailer.
Tire Load Rating
Don’t overlook your trailer tires! Tires have a load rating listed on the sidewall in the form of an index that ranges from 0-150 (99 lbs. to 7,385 lbs.) to indicate the maximum weight a tire can carry. (You can learn a lot more on tire load index here.)
When replacing tires, this index should meet or exceed the vehicle GVWR. Running tires rated below your vehicle’s GVWR will reduce its overall weight capacity and may cause instability and tire failure. Information on your vehicle’s towing specifications can be found in the owner’s manual or door sticker.
Tongue Weight
Tongue weight refers to how much downward weight is placed on the trailer ball. Tongue weight will typically be around 10 to 15 percent of the total trailer weight.
It’s important to note that tongue weight can be impacted by cargo placement on the trailer itself. As a general rule, it’s best to load gear as evenly as possible throughout the trailer. When loading an empty trailer, achieving the correct tongue weight will help prevent trailer sway or an overloaded rear axle on your tow vehicle.
Trailer Weight
This is simply the weight of the trailer, empty and unloaded. This rating will impact how much cargo you can haul in regard to your vehicle’s overall tow rating.
Vehicle Tow Rating (AKA Towing Capacity)
Another spec you’ll absolutely need to know is your vehicle’s towing capacity, often referred to as its tow rating. This is a spec provided by the manufacturer of your car, truck, or SUV. If you can’t find it on the automaker’s website or in the owners manual, a quick internet search will usually uncover it.
This will tell you how much weight the vehicle can safely tow, and it’s dictated by a handful of factors–including specs like engine horsepower, transmission, wheelbase, and GVWR.
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A Note on Weight & Trailer Brakes
You don’t have to be Isaac Newton to understand the correlation between weight and safe stopping, but it’s absolutely important to understand that, depending on where you live, your towing capability is likely also dictated by the legal requirement to use trailer brakes (and a trailer brake controller).
And most places use gross trailer and vehicle weight as guidelines in making that distinction. Again, it depends largely on your state and/or local laws or regulations, so it’s always a good idea to check with your DMV/BMW before you hitch up.
Our pals at Summit Racing created an in-depth video on trailer brakes and brake controllers. If you really want to get into the weeds on this topic, check it out here:
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