Good Sam RV Travel Guide & Campground Directory

Tow Vehicle Tips



For many RVers, a towable RV is the unit that best meets their RV/camping needs. For newcomers to the RV/camping lifestyle, the choice of a tow vehicle need not be confusing . . . with a little homework.

There are several tow vehicles on the market today that can be used in conjunction with your trailer. Some of these vehicles can also be used for daily commuting, while some are designed exclusively for heavy-duty towing.

But just what should you be looking for when shopping for a tow vehicle? The following tips will prove helpful when comparing tow vehicles.

Know What You Need
Before you begin shopping for your tow vehicle, there is some basic information you need to know regarding your trailer. Length, weight and height of your trailer, as well as what type of trailer brakes you're RV is equipped with, are important details. All of this information can be obtained from the RV dealer/manufacturer from whom you purchased your RV.

A word of caution about weight and weight ratings. There are several different measurements of RV weight - base curb weight, gross vehicle weight rating, gross combined weight, just to name a few, so it's important to understand these different ratings and keep them in mind when shopping for a tow vehicle.

Diesel Engines
More and more manufacturers are offering diesel engines in their vehicles. And many tow vehicle purchasers are immediately presented with the question "Should I buy a diesel?" Here's a quick look at the advantages of diesel engines.

Many argue that diesels are cheaper to operate, offering more miles to the gallon of fuel when compared to a gasoline engine. Diesel engines will usually last longer before an overhaul is needed. According to RV technical writer Bill Farlow, it is not uncommon for the light diesels used in small trucks to go 250,000 to 300,000 miles before overhaul. Engines in heavy trucks often exceed these numbers by hundreds of thousands of miles. All these add up to real economy.

Diesel engines are also known for their ability to develop a lot of torque at relatively low engine speeds; which translates into less internal friction; which in turn means better fuel economy.


Gear Ratios
When shopping for a vehicle, it's important to know and ask about its gear ratio. So here's a quick and somewhat simplified overview of gear ratios and why they are important when it comes to towing.

Engines turn fast to develop horsepower. But if the truck's rear wheels were connected to the engine, you would find that the engine couldn't develop any power. Therefore, gears are used to turn the wheels more slowly than the engine. Rear end gears reduce speed, and the gear ratio indicates the amount of this reduction. A ratio of 4.10 means the engine turns 4.10 times as fast as the wheels. So when looking for a tow vehicle, remember, a high numerical ratio gives more towing power than a low numerical ratio.

Other Necessities
Some other important areas to address when shopping for a tow vehicle include adequate brakes, suspension, transmission, engine, tires, and, obviously, towing capacity. In fact, many vehicles must be equipped with special towing packages offered by the manufacturer in order to tow a trailer. Remember, some of these trailers can weigh in excess of 10,000 pounds, so heavy-duty equipment is needed not only for hauling purposes, but for safety reasons as well. If you're heading down the mountain at a significant grade, you want to be sure you have sufficient braking power.

Tongue Weight
Tongue weight refers to the amount of the trailer's weight that presses down on the trailer hitch. Too much tongue weight can cause suspension/drive train damage, and can press the vehicle down in back, causing the front wheels to lift to the point where traction, steering response and braking are severely decreased. Too little tongue weight can actually lift the rear of the vehicle, reducing rear-wheel traction and causing instability which may result in tail wagging or jackknifing.

The folks at Ford offer the following tongue weight guidelines to ensure proper handling:

For trailers up to 2,000 pounds, tongue load should not exceed 200 pounds.

For trailers over 2,000 pounds, tongue load should be 10-15 percent of trailer weight.

For fifth wheel trailers, tongue load should be 25 percent of trailer weight.

To determine the proper tongue load for a 3,000-pound trailer, multiply 3,000 by .10 (10%) and .15 (15%) to obtain a tongue load range of 300 to 450 pounds. For a fifth wheel trailer weighing 3,000 pounds, multiply 3,000 by .25 (25%) to arrive at a tongue load of 750 pounds.

To measure actual tongue load, disconnect the trailer and place only the tongue - with the coupler at hitch ball height - on a scale. If the tongue load exceeds the upper weight limit, shift some of the trailer contents to the back. If the tongue load is less than the lower limit, shift the load forward.

Now let's take a look at the different categories of tow vehicles. For the most part, tow vehicles can be divided by the weights they can pull. For our purposes here, we will divide them into four categories: Light-to-Medium-Duty; Heavy-Duty, Extra-Heavy-Duty and Super-Heavy-Duty.

Light-To-Medium-Duty
This category includes several sedans, mini vans and light trucks that can tow trailers with weights up to 3,500 pounds (these are gross trailer weights). The trailers are mostly single-axle and are small-to-medium in length.

There are several vehicles on the market that can easily tow trailers of this weight. And the advantage of these vehicles is that they can be used on a daily basis - when the vehicle is not being used to tow the trailer.

Medium-To-Heavy-Duty
As we enter into this category, you'll discover that the weight ranges from here on begin to get a little gray. How a vehicle is equipped (gear ratio, engine and transmission), influences how much towing capacity it has. So the same vehicle model with different engines and gear ratios can result in a difference of towing capacity by 3,000 pounds or more.

For our purposes here, the medium-to-heavy-duty class of vehicle can tow 3,501-5,000 pounds (gross trailer weight). This category often encompasses dual-axle or large single-axle trailers.

Extra-Heavy-Duty
This category includes those trailers with 5,001-10,000-pound gross weights, and therefore includes some of the largest travel trailers and fifth wheels manufactured. Regardless of the make or model you're considering, it is important to ask about required equipment necessary for towing trailers in this category.

Super-Heavy-Duty
This class of tow vehicles is for those trailers weighing over 10,000 pounds. There are a number of vehicles that can be purchased for towing the heaviest of travel trailers and fifth wheels. And like the categories above, many of the same vehicles, when properly outfitted, can enhance their towing capacity by a few thousand pounds.

Another option for buyers looking in this category is to have their tow vehicles custom built.

As you can see, there is much to consider when purchasing a tow vehicle. So before you buy, make sure you know your trailer's weight and take the time to shop around, asking as many questions as needed to ensure you get the tow vehicle that will best tow your trailer. Best of luck!

Fifth Wheel Notes
Because fifth wheel trailers have a greater percentage of their weight on the kingpin than do conventional travel trailers, you must pay careful attention to the maximum allowable payload and gross vehicle weight ratings when selecting a tow vehicle for towing a fifth wheel.

Now that you're armed with some basic information regarding tow vehicles, it's time to begin shopping and comparing.