Trailer-towing staycations — the catchphrase for vacation travel close to home — have never been more popular than they are now. Neither have towable RVs, be they tiny teardrops, adventure-style campers, medium-sized tow-behind RVs, or the big 5th wheelers and toy haulers. All types of towable RVs have suddenly become the go-to mode of vacation travel because they afford road trippers the safest form of lodging with the best protection amid coronavirus concerns.
According to the Recreational Vehicle Industry Association (RVIA) 46 million Americans plan on taking an RV trip in the next 12 months. According to the study, those with the greatest interest in such trips are 18-34 year-olds. That means there are a lot of first-time RVers hitting the road with little or no towing experience, whether with a camper they just purchased or a rental.
Towing Handling Concerns
Being safe when towing a trailer requires making sure the tow vehicle and trailer are compatible. That’s where “tow ratings” come in.
Towing a trailer that’s “too heavy” or above the factory towing capacity for the vehicle towing it puts the driver and passengers at higher risk of an accident. The extra weight of the trailer pushing down on the hitch can overwhelm the steering and braking of the tow vehicle, especially when maneuvering for an emergency lane-change, cornering at highway speeds, or handling sudden side-wind gusts from passing big rigs.
A trailer that’s above the tow vehicle’s factory towing capacity may also damage the transmission, brakes, axles, and other drivetrain components of the tow vehicle. Towing a trailer that’s heavier than the factory recommends also puts a big strain on the vehicle’s cooling system, adding another area of concern.
So it’s very important for anyone who plans on towing a trailer of any type to understand the basics of tow ratings and towing safely. The last thing anyone wants is their staycation turning into the trip from hell because of tow vehicle or trailer-related issues.
Weight Carrying vs. Weight Distributing
The first thing anyone who is thinking of towing a trailer — be it a camp trailer, a trailer loaded with ATVs, or even a boat trailer— needs to know is how heavy a trailer your vehicle is capable of towing. This basic towing information can be found in the towing section of the vehicle owner’s manual.
It’s there that you’ll also find two very important towing terms related to hitches and trailering: weight-carrying and weight-distributing. Understanding the differences between these two types of hitches is critical if you intend to tow in a safe, prudent manner.
The weight-carrying trailer-towing capacity is the maximum weight the particular vehicle can tow safely in the conventional mode or with the trailer locked onto the hitch ball on the shank coming out of the hitch. This is the common way most trailers that weigh less than 3,500 pounds are towed.
Weight-distributing (WD) trailer-towing capacity, on the flip side, is when the trailer is attached to a special, non-factory-supplied, weight-distributing (load-equalizing) hitch assembly. A WD hitch utilizes supplemental steel bars, called spring-bars, the ends of which are typically attached to the trailer frame with chains. You see this setup on most RV-type trailers that weigh more than 5,000 pounds and are designed to be attached to the hitch on pickups.
The WD hitch spring-bars help lift and distribute the weight of a nose-heavy trailer more evenly across the tow vehicle’s front and rear axles, reducing the tendency for the vehicle’s tail to sag. A WD hitch, when properly adjusted, greatly improves the tow vehicle and trailer’s stability and handling characteristics.
A standard (weight-carrying) hitch doesn’t afford such adjustment. Consequently, a vehicle’s weight-distributing towing capacity, if it has one, will always be significantly higher than its weight-carrying towing capacity.
Most smaller cars, cross-overs, and SUVs’ trailer towing capacities are based on the standard, weight-carrying hitch. This hitch often comes installed from the factory or dealership or can be installed as an add-on aftermarket upgrade.
How Towing Capacity is Determined
Towing a trailer that exceeds the weight-carrying capacity as specified in the vehicle’s owners’ manuals or on the vehicle manufacturer’s website is a very real safety concern. It also creates some legal liability concerns, which I’ll discuss later.
First, tow ratings. These are set by the vehicle manufacturer at the time the vehicle is built on the assembly line. Tow ratings are like the vehicle’s VIN — once set, that number remains the same regardless of what modifications are made to the vehicle after it leaves the factory.
Tow ratings are based on extensive lab and field testing conducted by the vehicle manufacturer in accordance with the Society of Automotive Engineers (SAE) J2807 standard, which is a set of real-world tests designed to determine a vehicle’s safe towing limits.
This series of tests target handling, trailer sway, braking, accident avoidance maneuvers, acceleration, and the tow vehicle’s component durability. The test also includes driving up the Davis Dam, a 7% grade that runs eastward out of Laughlin, Nevada, for 11 miles to the top of the 3,500-foot summit in daytime temperatures of 100 degrees with the air conditioning going full blast.
When all is said and done, the vehicle manufacturer looks at all the resulting data and decides what towing limits to place on that particular make/model vehicle when it is “properly equipped.”
What Does “Properly Equipped” Mean?
Now there are some words with real weight. Properly equipped is the automotive version of an electrified fence between towing with the full blessing of the vehicle manufacturer and not. A properly-equipped vehicle has everything the manufacturer deems necessary to tow a certain load — the proper engine and transmission, the right cooling system, the correct bed and cab configuration (for pickups), the correct axle ratio, and the type of hitch setup, be it conventional (weight-carrying) or WD.
For example, many half-ton pickups, especially pre-2017 models, are limited to a maximum trailered weight of 5,000 pounds in the weight-carrying mode, while their three-quarter-ton stablemates are limited to less than 10,000 pounds towing on-the-ball.
Some Toyota pickup and SUV owners’ manuals state sway-control devices are mandatory on trailers weighing more than 2,000 pounds and limit towing speeds of those vehicles to less than 45 mph. Nissan’s towing guide “strongly recommends” the use of a sway-control device for all of their pickups and SUVs that are not equipped with Vehicle Dynamic Control (VDC) when towing trailers weighing more than 2,000 pounds.
Finding Your Vehicle’s Tow Ratings
Every vehicle manufacturer has a special website that explains and defines tow ratings and towing equipment requirements for vehicles that can tow. Good search words to find them are the vehicle manufacturer name followed by “RV and trailer towing,” “towing guide,” and “RV towing guide.”
Odd as it seems, such information isn’t always easy to find. For some reason, some of the big vehicle manufacturers place tow ratings and towing requirements on their fleet websites, not on the consumer side.
For example, Ford has its detailed towing data for 2004-2021 vehicles on the fleet site under Towing Guides. GM keeps theirs under Trailering Guide on the fleet website, as does FCA/RAM Truck in the Towing & Payload Capacity section. (Check here for Nissan, Toyota, Mazda, and Honda towing guidelines.)
Tongue Weight: The Real Concern
One trailering item that is consistent across the board for all vehicles that have a factory tow rating is the vehicle’s tongue weight (TW) capacity. Tongue weight, expressed in pounds, is the downward force a trailer’s tongue places on the hitch ball and, therefore, on the rear of the tow vehicle. The proper towing setup requires 10-15% of the trailer’s weight be on the hitch.
The greater the tongue-weight, the more the rear of the vehicle drops and the front rises. Too little weight up front creates steering and braking problems. The smaller and lighter the tow vehicle, the more important it is to pay close attention to how much tongue weight the trailer is putting on the hitch. Generally, it’s best to keep the trailer tongue weight 15-20% less than your tow vehicle’s maximum TW capacity.
Like weight-carrying and weight-distributing ratings, tongue-weight has been derived by both the vehicle and the hitch manufacturer as the safe limit for that product. Towing a trailer that is above the tongue-weight specified by the vehicle manufacturer classifies the vehicle driver as being negligent, which means the driver may be liable in the event of an accident.
As the online Dodge towing guide states: “Incorrect tongue weight could result in increased yaw or vehicle instability. A negative tongue weight could unload the rear suspension of the tow vehicle, decreasing vehicle stability.”
If the weight of the trailer, the tongue-weight, or hitch load limitations as established by the manufacturer are not adhered to, the driver of the tow vehicle is considered to be towing in a negligent manner.
Trailers that weigh more than 3,000 pounds are required to have brakes. The conundrum here is even if you abide by tongue-weights and use a weight-distributing hitch to meet the “properly-equipped” standard, your towing setup may still not be correct. It’s all about the trailer braking system.
Most RV camper trailers utilize electric brakes. But there are many boat trailers, teardrops, and off-road, adventure-style trailers on the market equipped with surge-type brakes. Surge-type brakes have a hydraulic master cylinder in the trailer tongue which uses the force of the trailer pushing against the tow vehicle to apply the trailer’s brakes.
What is at issue here is the majority of weight-distributing hitches interfere with (or disable) the surge-type brake system functioning properly. Sway-control devices, like those required by many of the smaller SUV and pickups to tow larger loads, virtually stop a surge-brake system from working at all.
Don’t blame yourself for not knowing all these little caveats about towing. Automotive manufacturers are always pushing for a marketing edge, and tow ratings play a big role in that edge. Regardless of how small the difference is between two competing vehicles, the one with the bigger towing capacity is somehow perceived by many consumers as being the better vehicle.
That’s why almost every ad you see on TV shows a pickup or SUV towing at or very near its upper limits. (The vehicle being shown is properly equipped, as the superfine print under the ad says.) This leads the average buyer to believe their own vehicle can do the same. And, it can — as long as it is properly equipped for the trailer being towed.
No Escaping Tow Ratings
Be smart. Do your homework. Find out what your own tow vehicle can tow and what it needs to be properly equipped to do it. Trailer weight capacity issues create some interesting towing calculations and confusing legal issues for anyone who attaches a trailer to a hitch.
And, no, you can’t work around a vehicle’s towing capacity limitations by upgrading to a stronger hitch, say from a Class II to a Class III, or a Class III to a Class IV or V, or by adding helper springs, air-adjustable shocks, or airbags for additional rear suspension lift/support.
We have to live with and abide by the tow ratings the vehicle manufacturers set. If you ignore the vehicle’s tow ratings, and words such as “properly-equipped” and “weight-carrying limit,” then you assume all responsibility for what happens on your road trip RV staycation. Tow smart. Tow safe.