How Tow Dollies Works

towing with an RV
Towing a vehicle can make an RV vacation go much smoother.
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Acquiring tow dollies can top the to-do list for a variety of circumstances. Say you just bought a big RV and want to head out on a cross-country voyage -- towing a spare vehicle along so you don't have to maneuver the motor home every time an errand pops up can be a huge help. Or, suppose your family is moving and you have one moving truck, two cars and only two drivers. Someone is going to need to double up, unless you want the move to become as tricky as one of those old word problems you were given back in elementary school.

A tow dolly elevates the front wheels of the vehicle being towed and is useful in a number of situations. Whether it's the best choice for the job depends on the particulars of each individual situation. We'll dive deeper into that choice in a bit; for now, let's examine some of the other options out there.


The easiest way to look at towing is how many wheels of the car will be off the ground. We just noted that with a towing dolly, that number would be two. There are also ways to tow with all four wheels elevated and with all four wheels on the road. A trailer -- generally referred to as a car hauler -- is used to tow four wheels up, while a tow bar is necessary to tow four wheels down. There's no universally preferred method: A lot depends on factors such as the weight of the vehicle being towed, whether that vehicle is a front-wheel-drive versus a rear- , all- or four-wheel-drive, how much total weight your towing vehicle can handle and how much money and time you're willing to spend dealing with the setup.

On the next page, we'll explore why a tow dolly might be just the ticket if you need to haul a vehicle.


Purpose of Tow Dollies

Tow dolly
Tow dollies can be useful in all sorts of situations.
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As we noted on the previous page, tow dollies come in handy for a variety of situations. Whether used for hassle-free sightseeing during an RV trip, because you're short on drivers for your big move or because your teenage son's car broke down and needs to be towed to the nearest mechanic, a tow dolly can be just the thing.

­However, tow dollies have faded in popularity somewhat after people came up with ways to modify cars so they could simply use tow bars to pull them. Despite this, many remain loyal to their tow dollies for a number of reasons.


Probably foremost of these helpful uses is the fact that any front-wheel-drive automatic can be pulled with a tow dolly. Many types of automatics must be modified with accessories like lube pumps and axle disconnects to spare the transmission if you want to haul them four wheels down. This can be handy in a few situations, like if you suddenly need to help out with a friend's broken-down car or make a quick auto swap.

Another purpose of tow dollies has to do with the odometer. On some vehicles, if the front wheels are rolling -- even if the ignition is off -- the odometer keeps adding on miles. When the front tires are elevated, this isn't an issue with these types of cars because a tow dolly keeps your towed vehicle's mileage at the same count as before you began your trek. Again, people have worked out ways around the problems, but if you're looking for a simpler tow, a tow dolly might be your answer.

Keep in mind, there are lots of tow dollies out there for the taking. Before you haul out your checkbook and get your dolly jollies, let's examine which type makes the most sense for your vehicle and find out more tow dolly information.


Choosing Tow Dollies

tow dolly
Tow dollies can weigh more than 500 pounds (225 kilograms).
Photo courtesy Master Tow

Choosing tow dollies versus other available towing accessories on the market can get confusing, but the thing to keep in mind is what kind of vehicle you're looking to tow. When towing, the make and model of the vehicle can affect whether it's possible to simply hook it up and go or if you need to make some modifications to it in order to get towing.

­The biggest issues tend to crop up if you have a four- , rear- or all-wheel-drive vehicle. In many instances, the vehicle's transmission will be shot unless you disconnect the driveshaft and possibly install other accessories as well. Also, as we noted on the previous page, having a manual versus an automatic transmission will factor into the equation. The best advice to follow is consult the manufacturer for information on your particular vehicle to help you decide if a tow dolly or towing four wheels down is most appropriate for your situation. Some vehicles are good to go as is; some just need a quick, manageable tweak; and others are much more challenging and expensive to prepare for towing. If you're considering the expense of towing four wheels up, these issues can be largely avoided with a tow dolly.


Knowing the weight of the vehicle being towed and the various weight ratings of the tow vehicle and hitch is also fundamental. If you plan on hauling around a little sedan most of the time, a tow dolly might be a good idea. If you want to take a large SUV along for the ride, you may need to keep shopping. This is because tow dollies themselves can weigh quite a bit -- in most cases 500 pounds (225 kilograms) or more. All that weight might put you over the limit, or at least force you to purchase additional equipment such as onboard brakes and other safety features. (For safety's sake, extra brakes and lights are a good idea at any weight.)

Along the same vein, you should be cognizant of the weight ratio between the towing vehicle and the vehicle being towed. U-Haul, for example, advises people renting their tow dollies to keep at least a 750-pound (340-kilogram) buffer between the weight of the front vehicle and the one in back [source: U-Haul]. You must also keep in mind how wide your towed vehicle is because different tow dollies have different maximum vehicle widths that can't be exceeded.

Your best bet is to do some research and carefully consult with the vehicle manufacturers and a towing expert. Their advice can help you choose an appropriate dolly or alternate towing methods that are best suited to your needs.


Using Tow Dollies

Tow dollies are generally installed in the same manner as other hitch systems. You need to verify that your hitch and towing vehicle meet the necessary weight ratings and then check out all the components of your vehicles. Although you should follow the instruction manual closely for your particular dolly to complete this process, here are the basics involved.

The first thing to do when using tow dollies is to make sure the hitch ball is at the correct height. Then, securely place the coupler on the hitch ball and connect the safety chains between the tow dolly and the hitch, crisscrossing them beneath the tongue. If you have tow dolly lights and brakes, now is the time to connect them.


­Double check to make sure all the weights are OK (discussed in more detail in How Towing Weight Distribution Systems Work), and find a spot on level ground to load the vehicle on the tow dolly. Whether your towing dolly has tilting ramps or pullout ramps, unlock them and rest them on the ground. Drive up to the ramps and look to see if your vehicle is centered precisely, making sure everything will clear the ramps without getting damaged. Proceed to drive slowly up the ramps and onto the tow dolly's platform, then return the ramps to their proper positions. If the towed vehicle is an automatic, put it in park; if it's a manual, put it in first gear. Temporarily apply the parking brake and lock the steering wheel in the straight position. This is a crucial step -- if your steering wheel doesn't lock automatically, you must manually immobilize it.

Next, make sure the tire straps are the right size for the vehicle, and place them snuggly around the tires. They need to be positioned carefully so there aren't any twists in the material or contact with fraying metal or the vehicle's brakes and suspension. Tighten the straps and lock the ratchet, then you can attach safety chains between the dolly and the towed vehicle. You can also install lights on the towed vehicle to make other drivers aware of your cargo and help to keep the roads safe. Finally, release the parking brake, remove the keys, lock the door and you're good to go.

There are a few more items to note when using tow dollies. Whenever you plan on towing a vehicle, you want to be sure to hook up the tow dolly to the towing vehicle before you load the vehicle to be towed. Also, the towed vehicle should always be loaded facing forward. If the weight of the engine is in the back of the setup, the vehicle will likely sway uncontrollably, creating very dangerous driving conditions. If your car has a mid or rear engine, you'll probably want to look into getting a trailer in order to tow four wheels up.

Avoid sharp turns while pulling your dolly or the two vehicles could collide with each other. Follow normal towing safety precautions as well, some of which you can read about in Trailer Towing Safety. Never allow people to ride in the towed vehicle, and remember, it's a smart idea to install a braking and lighting system if your dolly didn't come with one.

Your tow dolly is loaded and you're ready to hit the road. However, there are a few issues with tow dollies you'll need to keep in mind as you drive off into the sunset.


Problems with Tow Dollies

tow dolly
Lots of people enjoy the ease of tow bars over tow dollies -- you might too.
Alan Levenson/Stone/Getty Images

One of the biggest problems with tow dollies is that you can't back up. A few brave souls have succeeded, but most experts advise -- and most instruction manuals insist -- on a no backing-up policy. Backing up can damage the vehicles and dolly, as well as cause a serious incident like jackknifing. If you need to momentarily reverse, you'll have to unhook and move the towed vehicle, unhook and move the dolly, and then rehitch the equipment all over again to hook everything back up. For seasoned towers, this process might not take too much time, but it can still be a hassle that some might want to avoid. Keep in mind though, even if you use one of the other systems, like tow bars or trailers, you probably won't be doing much backing up with them, either.

You'll need to get low in order to inspect the next cluster of potential towing problems. If there are any parts hanging underneath the towed vehicle -- like spoilers, air dams and ground effects -- these should be removed before the vehicle is loaded onto the tow dolly, or they could become damaged.


Some RVers have had unfortunate accidents outside the normal realm of towing perils. If you hit a large bump or pothole, for example, the towed vehicle can jump out of proper alignment. The challenge of trying to get a car off a dolly when you're unable to drive it can put a real black mark on vacation memories. Also, if you need to tow an empty dolly without the towed vehicle's suspension in action, it can vibrate strongly and make driving a challenge. This can also damage the dolly, especially if the tires are left at their full psi.

Tow dollies can mean more maintenance and add more items -- and costs -- to the already lengthy checklist. Also, as we mentioned before, they add significant weight that needs to be factored in. Dollies can add anywhere from around 500 to 1,500 pounds (230 to 680 kilograms), which will definitely impact the trailer weight calculations.

­Some vehicle manufacturers' warranties will be invalidated if a vehicle is towed by certain methods. So if your car is still under warranty, you'll definitely want to check into this before acquiring a towing system. This sort of information may be in your owner's manual or some other place that's easily accessible. If you need to have a dealer or manufacturer give you an answer, don't take a verbal one -- get the OK in writing. Also, tow dollies are often considered additional vehicles and need to be specially licensed and equipped if you're driving through some states. This can be especially important if your towed vehicle is over a certain weight, so thoroughly check out the laws of the land before you hit the road -- if you haven't already bought supplemental brakes, you may be heading back to the store before your big trip can begin.

Another factor worth mentioning is the space that a towing dolly takes up. They can be hard to maneuver -- it's often a two-person job -- and when they're not in use they can be a bit of an eyesore. Some solutions are available. For example, some RVers will drive their RVs right over the slanted portion of the dollies, so only the tire end peaks out, concealing a great deal of the apparatus.

If you're still convinced a tow dolly is the thing for you, continue to the next page for great towing and automotive links.


Lots More Information

Related HowStuffWorks Articles
More Great Links


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