Trailers are wonderful things. They can carry cargo, including cars, furniture and boats. You give you place to live on vacation. But they must also be towed. Towing gets you there, but bad technique can break things and lead to accidents. So while towing is good, it's important to remember the fundamentals. You need to choose the right hitch, tow vehicle and trailer for what you are doing.
Hitches
First of all, you must have a hitch. In the US the smallest hitch is a Type I, which is rated at 2,000 pounds (900 kg) of total weight and can easily be attached to a bumper. You can move a lot with 2,000 pounds (including some race cars) but with some HDTVs clocking in at over 200 lbs (100 kilos), a ton can disappear quickly. Particularly when the weight of the trailer is included in that number. Small sailboats, motorcycles and pop-up campers are usually fine with a Type I hitch. A Type II hitch is tied into the vehicles frame and good for around 3,500 lbs. Type III and IV hitches are big boys, good for 5,000 pounds without weight equalizer bars, and 10,000 with it. A Type V hitch is rated at 14,000 lbs. Anything bigger is found on a commercial vehicle. A goose-neck hitch is a conventional ball, mounted in the center of a pickup bed. A fifth wheel is a smaller version of the hitch used on full sized semi tractors, and also located on the bed of a pickup.
Most hitches you will use will be of the ball type, and in America the balls come in three different sizes, measured by diameter: 1 7/8, 2 and 2 5/16 inches. You must use the correct ball size for your trailer. If you don't the hitch won't go on, or it might slip off.
Class II hitches and up may include a stabilizer bar, which reduces the trailer's tendency to wander. An equalizer is a set of adjustable arms that equalize the weight on the rear axle of the tow vehicle and the front axle on the trailer. They make the trailer a lot more controllable.
You must also chain your trailer to the tow vehicle to keep it from taking a flight of fancy should the trailer become unhitched. The chains should be loose enough to allow for turns, but not drag on the ground, which is hard on the chain. If your trailer has a brakes, there will be a wire to activate them in the event of separation that must be attached to the tow vehicle.
Weight
Weight is everything when trailering. You must consider the weight of the tow vehicle, the weight of the trailer and everything aboard either vehicle, and most particularly the trailer. For all trailers there are two types of weight, tongue weight and gross vehicle weight. Tow vehicles and hitches are rated for both types of weight. Tongue weight is simply the amount of weight that presses down on the hitch. Tongue weight should be between 10 - 15% of the total loaded trailer weight. You can measure tongue weight, using a bathroom scale and the right lever to reduce the loads to something the scale can survive. If you keep your numbers in the 10-15% range tyou can be fairly confident that the load is distributed properly. Moving the weight to far back lightens tongue weight, too much means there is too much weight forward. Either can make the trailer unstable.
It is important to remember that everything you load counts toward trailer weight, including you, and that last bag of Doritos. If you are moving a race car, you will not only have the car to consider, but your spare parts, tools, canopies, tires and wheels and a whole lot more stuff to move. It all weighs and it all has to be counted. The weight of your tow vehicle also matters. Tow vehicles are rated with both trailer weight and total weight, including the vehicle. The larger the tow vehicle in comparison to the trailer, the easier will be the tow. You cannot necessarily trust the manufacturers stated weight for your tow vehicle when figuring things. After all, you and your crew or family count. As does everything loaded into the tow vehicle. And some vehicles weigh a lot more than the manufacturer intended, such as conversion vans. Putting too much weight on the tow vehicle can lead to safety problems (such as overloaded brakes), and breakdowns. Think transmission failure.
Trailers
You have a lot of options here: Open or closed, fifth wheel or tag-along. Here is an introduction.
For cars and cargo that doesn't need shelter you may choose between an open or enclosed trailer. Each has it's own advantages. Open trailers weigh less, cost less and are a lot easier to load. Particularly when you've cracked up your race car. Open trailers come in two types, those with flat bed, and those who have a divided bed. The one piece flat bed models are more flexible, but harder to tie down. A trailer with a center opening is easier to tie down, and you may be able to pull of significant under-car maintenance with the car still on the trailer. Which reduces the need for jack stands. Open trailers of all types are a lot easier to tuck away, unseen.
Enclosed trailers cost more, weigh more and may produce more aerodynamic drag. But you can throw a lot more stuff in them, and discretely. They can serve as a temporary garage, may offer elaborate storage provisions and keep your precious tires away from UV radiation. That frees up a lot of space in the tow vehicle. Which you probably won't be able to resist using.
Most trailers are tag-alongs, which means they simply attach to the back of the tow vehicle. Almost all small trailers are of this type, since nothing more is needed. Goose neck and fifth wheel trailers are used for heavier loads. They offer greater stability and a tighter turning radius, since part of the trailer is over the tow vehicle. But you can only use those hitches with a pick-up truck or a tractor type vehicle. They are too large for anything less than a 3/4 or 1 ton rated truck. With such a trailer, you can forget using the truck bed for storage. But the trailers are often large enough to make up. Fifth wheel campers can be really nice, I've seen some that rivaled my home.
Single axle trailers are okay for very small loads, stability improves markedly with each additional axle. That's not considering any additional weight. Multi axle trailers don't want to wander so much. They do cost more through a turnpike toll both. But if you're towing a full sized car, two axles are a minimum.
Brakes and Lights
You want trailer brakes. In fact, trailer brakes are mandatory in most states for all but the smallest trailers. There are two types of brakes, hydraulic surge and electric brakes. Surge brakes are cheaper, require no controller but they cannot be used to slow you down. Electric brakes draw power from the tow vehicle (uprate that alternator!), a brake controller and the correct wiring harness. Their virtue comes from the fact that they take some of the braking load off the tow vehicle, which was often designed to stop only itself. You don't need to tow across Donner Pass to appreciate what trailer braking can do for your peace of mind. And if your trailer starts to shimmy under load, a tap of the trailer's brakes will usually settle it down.
A set of night and brake lights are almost mandatory, and most states require turn signal repeating in all but the smallest trailers. It is good practice to check trailer lights before towing any significant distance. Most people don't use their trailer every day, and are often surprised. Reflectors are often mandatory and always wise. As is the addition of additional gold marker lights. They make your trailer visible so people won't try to drive through it. Again you must install and match your wiring harness to the trailer.
Tires
Trailer tires often forgotten by people new to towing. It is important to remember that trailers often sit for months or longer in the off season. Sitting is not good for tires and neither is sunlight. If you purchase an older trailer and can't date the tires, replace them. The tires need to be rated for trailering. For light loads standard car tires will do, but trailer tires are very tolerant of heavy loading. Carry a spare. Trailer tires do fail, just like automotive tires. And for God's sake check inflation.
Tow vehicles: Bigger is Better
While bigger is better may not apply to sex, it certainly does for towing. No tow vehicle is ever 'overly endowed'. Small equipment is good only for small jobs. A formula ford may be towed behind a Ford Ranger. But larger vehicles have stouter engines, transmissions, brakes and simply more weight to match up with the load. Trucks are usually better than cars or SUV's for towing if for no other reason than their stiffer suspensions are designed more for loads than soft ride. Vans work well, but some conversion vans are very heavy with all the additions..
Engines
Tim Gordon of Red Diamond Racing Engines builds a lot of tow motors for his customers. Racers often tow a long way, particularly top SCCA National and Trans Am drivers who may span the US to race. Tow motors are built for two things: reliability and torque. He told me that he often strokes the engines, because it gives more torque and high revs are not a consideration for towing. He also changes the cam, with most motors having a torque peak between 2,500 and 3,500 RPM. Before he selects the cam Tim always finds out what rear axle ratio the vehicle has. If the axle ratio is lower (which is signified by a higher number, as the ratio compares the number of driveshaft to axle revolutions), then he will choose a camshaft oriented toward slightly higher revs. The lower the axle ratio, the more weight the vehicle will pull, at a sacrifice of speed and gas mileage.
For towing a car or camper, the minimum is a V-8 of around 350 cubic inches (over 5.0 liters), although the Ford 3.5L twin-turbo ecoboost engine replaces mass with technology. A motor that size has a enough torque to pull most loads with reasonable fuel economy, a plus when the vehicle's primary use is not towing. The more you tow, the longer the distance you tow, the bigger the motor. Think of it this way, a little guy can often lift a lot of weight, but a big guy usually lifts the same weight with greater ease. For reliability's sake you want a motor that doesn't work that hard. Bigger motors also come with bigger trannies, bigger everything. People who make long, or many tows should consider moving to a V-10, 454, or a diesel. Diesel engines have improved radically in the past dozen years, with much improved mileage, reduced noise and good fuel economy. Diesel fuel mileage is far less affected by heavy loads then a gas engine. Combined with stump pulling torque, diesels make a prime mover, if you can afford the initial purchase. Separate oil coolers contribute to engine longevity.
Transmissions
Towing is hard on transmissions. Transmissions are rated by torque, and pulling heavy loads stresses them to their limits. Standard shifts are still the champs for control and reliability but automatics have made a lot of progress in the last decade, and are now quite viable. Automatic transmissions are more prone to failure, though if you avoid misuse they can work nicely. You must be careful to observe your vehicle's gross weight limits and gear restrictions. Overdrive gears, designed to maximize highway milage, are often not robust enough for towing. Check your owner's manual. My race team learned that the hard way when a transmission blew up on the way to Summit Point. Which sent the tow rig and trailer sideways on Interstate 70. Blew a tire out as well.
A transmission oil cooler must be installed, and you need to pay close attention to fluid levels. Generally transmission coolers are standard on 3/4 ton trucks or larger, and are included in an optional trailer package. They can save you a lot of grief and money if you tow. In fact, the 3/4 ton truck can prove more affordable overall. They really don't cost much more than their 1/2 ton bretheren once the lighter trucks have been optioned for towing, and start out with a lot of heavier duty stuff that might not even be in the option book.
You can shade those requirements a bit if you tow only very short distances, or very rarely. Mid Ohio Sports Car Course is only an hour from my driveway. I could cheat a bit heading there. Summit Point Raceway is seven hours across the Pennsylvania Turnpike. No cheating allowed going there.
Motor homes make good tow vehicles, if you're not in a hurry. Their large size means they get lousy gas mileage, but there's a lot to be said for taking your bed with you. I'd like one for the track, so I could get there, unload my awning and crack a beer without worrying about setting up my tent, or my sleeping bag. The same 6,000 pound mass that makes them petrosuckers also makes the trailer seem a lot lighter, and less likely to step out. One the down side, they are expensive to repair, as virtually nothing is accessible. A transmission change in a motor home costs about twice what it would in another vehicle, and the mass makes them hard on trannies.
Grassroots Motorsports does periodic articles on motor homes and trailering. They suggest that conversion vans cannot be used to tow at all, the conversion absorbs all the extra capacity built into the van. Still, I know several people who tow regularly using such a van. Many are built on 3/4 or 1 ton truck frames with the right V-8, and can be found quite inexpensively used. They're also useful as people movers when you're not towing. GRM also suggest thats if you tow with a motor home you look hard at upgrading shocks, springs and sway bars, as they can make the drive and the tow a lot more pleasant, particularly in a crosswind.
If you tow very occasionally you may wish to rent a tow vehicle and trailer rather than purchase. It's cheaper and offloads the maintenance.
Hitting the Road
Loads move and they can move you. Many rollovers are caused when a load shifts inside the trailer. So everything must be absolutely secure for saftey reasons. After you have calculated the total weight to be moved, and balanced the load so that the weight is evenly distributed, you need to make sure it stays put. Everything must be secure.
Tie downs are very useful items. To secure a car you need to use straps at least two inches wide. We used three-inch straps, with rachet, at each corner of my race car. Thicker straps cost more, but are much stronger. Plus extra strength can save you if something breaks. Keep the excess nylon tied up, and try to keep them out of the sun, as ultraviolet light can break them down over time. In towing a car, never attach to the suspension, always to a frame member. Good straps of the rachet types are plenty strong enough to bend suspension parts. Imported cars are often easy to tow, as they have tie down hooks pre-installed for shipping. And I wouldn't trust your bumpers, unless you can get to a mounting point. Modern bumpers are plastic on the outside, which won't hold.
When hooking up the trailer, attach the trailer with anal retentive care. The ball must be tight. The hitch must be tight. The chains hung with the attachment hooks open toward the ground, and the disconnection brake set. Then check all the lights on trailer and tow vehicle, including the turn signals. Go over tire air pressure, oil, brake fluid and transmission fluid levels. Top off for departing. This is a good habit to build, because it's a habit that will get you there safe. And take the time for a light check before you leave. Using your turn signals doesn't matter if the bulb is burnt out or the wiring harness lose.
Most of all, take your time. Unless the trailer is extremely light your tow vehicle will feel the weight. Wind will hit you harder. Your center of gravity has moved and braking distances substantially increased. Remember this: that if your trailer starts to fishtail behnd you, stabilize it with the throttle rather than the tow vehicle's brakes. Braking, or even lifting, will only make the trailer want to step out even more. When backing you pull forward to steer the trailer. In reverse the trailer will go wherever you've pointed it and once it has charted a course the only way to change is to go forward again.
Good trailering technique can take you and your possessions almost everywhere, and offer you decent accommodations once you've arrived. But breakdowns and accidents can ruin the most anticipated trip. There is no magic to trailering. A good trip begins with common sense and preparation. So prepare!