How Much Towing Capacity Do You Need?

Whether you have a vehicle you intend to use for towing or are in the market to buy one, tow capacity is a critical first factor to understand and calculate before you hit the road. 

The correct calculations will ensure many opportunities for heavy-duty work or year-round adventures that can be pulled off safely and without mechanical strain on your vehicle. 

What is tow capacity?

In simple terms, tow capacity is the maximum weight you can safely pull behind your vehicle. Not to be mistaken for payload capacity—the amount of combined weight your vehicle’s (truck) bed and cabin can carry— tow capacity is only a measure of what your vehicle can pull or tow. 

Typically, towing capacity is higher than payload capacity since the trailer axles (vs. vehicle axles) support most of the weight in towing. It can help to think of it like the human body; typically, we can pull more weight than we can carry. 

How is tow capacity calculated?

Tow capacity is not a single number expressed in pounds but rather a series of calculations that involve:

• Gross combined vehicle weight rating (GCVWR) - the total weight of a vehicle, including its gas, cargo, passengers and trailer
• Curb weight - the weight of your vehicle when filled with gas but void of passengers and cargo
• Specific vehicle configurations – the arrangement of components (e.g., body style, engine layout, drive train and axel configuration) within a particular make and model of a car or truck

To calculate tow capacity, subtract the curb weight from the GCVWR to calculate tow capacity:

***   GCVWR – curb weight = towing capacity  ***

Suppose you’re wondering whether there’s a quick and easy way to know a vehicle’s tow capacity without doing the math. In that case, we have good and bad news: while vehicle manufacturers publish tow capacity in the owner’s manual and on the inside panel of the driver’s door, this calculation assumes one driver and an empty cabin and truck bed. 

In other words, if you plan to bring along passengers and their associated cargo, the manufacturer’s given calculations may not be accurate. This is why it's essential to know how to calculate tow capacity and always stay below 10% of the maximum established limit. Additional passengers, gear or equipment and load shifts should be expected and can breach your vehicle’s towing capabilities.

What happens if tow capacity is exceeded?

No one sets out to strain or stress their vehicle, but unfortunately, it happens. On the less serious side, your vehicle will struggle to reach the desired speed if you exceed the established tow capacity. More significant safety concerns arise regarding how long it will take to brake or the space needed to turn corners. 

Impending accidents and traffic violations aside, extensive damage can be done to your vehicle’s frame and suspension, costing hundreds if not thousands of dollars in repair since warranties are voided when tow capacity is breached. There’s also the potential for your vehicle to overheat if you try to pull more weight than your car is designed to handle. 

Other towing terminology

We’ve discussed curb weight, GCVWR, specific vehicle configurations and described the difference between tow capacity and payload capacity. Now let’s look at some other towing terminology you might see listed on the sticker of your new vehicle or overhear in general towing conversations:

• GAWR – Gross axle weight rating (GAWR) refers to the maximum amount of weight one axle of your vehicle can support. This number will typically vary between the front and rear axles since they are composed of different materials and diameters. It’s rare to find a vehicle that has a 50-50 weight balance between the two axles.
• GTW – The total weight of your trailer and its cargo are represented by gross trailer weight (GTW). If your towing capacity is less than your GTW, you run the risk of damaging your vehicle, your trailer, or both, and this can pose a danger to yourself and other drivers on the road. 
• Dry weight – Dry weight refers to how much your vehicle weighs with no cargo or required fluids. You will not need to know your vehicle’s dry weight for most towing calculations, but you may see it listed on vehicle specifications. 
• Tongue weight – The amount of force pushing down on a trailer hitch by the tow load is your vehicle's tongue weight (TW). Depending on how the load is distributed on the trailer, the tongue weight can vary. 
• Payload capacity – As mentioned earlier, payload capacity refers to the total amount of weight your vehicle can carry. It includes everything in the cabin, cargo area and bed of the truck. 

Does payload capacity matter?

Payload affects your towing capacity and is usually the limiting factor for most people hauling items. Most manufacturers list payload capacity in each vehicle's owner’s manual, so it’s rare that you’ll ever have to calculate this number independently. Sometimes, payload capacity will be written as a statement that warns of the combined weight of passengers and cargo that should not be exceeded. But if you want or need to calculate payload capacity, here's how you do it:

• First, find the combined weight of your vehicle.
• Next, add the weight of all the passengers and cargo within your vehicle.
• Finally, subtract your vehicle’s curb weight (the weight of your truck and all the fluids it needs to function but with no people or cargo inside).

Remember, if you exceed your vehicle's payload capacity, you may damage key mechanical components, voiding your vehicle’s warranty.  

Know before you tow

Before you embark on work or recreational adventures that require towing certain items, be prepared and informed of your vehicle’s limitations. Suppose the trailer or items you tow exceed tow capacity or you must navigate new or challenging terrain. In that case, it may be best to seek the help of professionals who can help you avoid an accident, prevent irreparable damage to your vehicle and prioritize safety.