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Must-Know Trailer Info

Posted in How To on May 1, 2000
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An equalizing hitch transfers weight off the tow vehicle’s rear axle and shifts it to the front axle and the trailer’s axle. A friction-style sway controller is shown here as well. An equalizing hitch transfers weight off the tow vehicle’s rear axle and shifts it to the front axle and the trailer’s axle. A friction-style sway controller is shown here as well.
There are a multitude of ball mounts, from no-drop to a 6-inch drop. These can be reversed to gain hitch height as well. There are a multitude of ball mounts, from no-drop to a 6-inch drop. These can be reversed to gain hitch height as well.
Equalizing hitches are available with adjustable shanks to set the ride height. Equalizing hitches are available with adjustable shanks to set the ride height.
Airbags such as these Air Lifts provide an adjustable weight-carrying capacity. However, you never want the weight to exceed the axle capacity. Airbags such as these Air Lifts provide an adjustable weight-carrying capacity. However, you never want the weight to exceed the axle capacity.
The small box is a breakaway connection. In the event the trailer becomes disconnected while it’s being towed, the lanyard pulls a pin that closes the circuit to the trailer brakes. A small battery supplies the current for the brakes. The small box is a breakaway connection. In the event the trailer becomes disconnected while it’s being towed, the lanyard pulls a pin that closes the circuit to the trailer brakes. A small battery supplies the current for the brakes.
When loading a vehicle onto a trailer, some form of support should be used at the rear. It can be a simple adjustable jackstand, a fold-down support, or a drop-down built into the trailer. When loading a vehicle onto a trailer, some form of support should be used at the rear. It can be a simple adjustable jackstand, a fold-down support, or a drop-down built into the trailer.
The tongue provides a spare-tire mount. Note the jack mounted to the side of the frame. It’s mounted to a receiver so it can be removed or mounted lengthwise when it’s not in use. The large support bracket is a mount for a removable winch. The tongue provides a spare-tire mount. Note the jack mounted to the side of the frame. It’s mounted to a receiver so it can be removed or mounted lengthwise when it’s not in use. The large support bracket is a mount for a removable winch.
These “P” metric radials work as trailer tires, but their sidewall strength and capacity aren’t up to the trailer’s rated capacity. We don’t recommend these, except for emergency situations. These “P” metric radials work as trailer tires, but their sidewall strength and capacity aren’t up to the trailer’s rated capacity. We don’t recommend these, except for emergency situations.
Vehicles should be secured properly. The tie-down strap goes to the axle and trailer frame. Note the fixed wheel chock. Not only does this locate the vehicle at its proper balance spot, it helps secure it from movement. Vehicles should be secured properly. The tie-down strap goes to the axle and trailer frame. Note the fixed wheel chock. Not only does this locate the vehicle at its proper balance spot, it helps secure it from movement.
Tires designed for trailer service are marked as such. Tires designed for trailer service are marked as such.
This flush tie-down appears to be bolted onto the plywood floor, but it wouldn’t be anywhere near strong enough. In this case, the bolts go through the wood into the trailer’s frame. This flush tie-down appears to be bolted onto the plywood floor, but it wouldn’t be anywhere near strong enough. In this case, the bolts go through the wood into the trailer’s frame.
Trailers such as this flatbed are reasonably priced. Their versatility allows them to be used not only as 4x4 haulers but in a wide variety of applications. Trailers such as this flatbed are reasonably priced. Their versatility allows them to be used not only as 4x4 haulers but in a wide variety of applications.
Fully enclosed trailers offer a few more benefits, such as security from the damaging elements, be they natural or human. Fully enclosed trailers offer a few more benefits, such as security from the damaging elements, be they natural or human.
Another advantage of an enclosed trailer is the portable “minishop” it contains. Another advantage of an enclosed trailer is the portable “minishop” it contains.

As we attend various 4x4 events, we see an increase in the number of play toys that are being trailered rather than flat-towed or driven. One reason for the increasing rate of trailered rigs is that some vehicles have extreme modifications. The mods make them not quite street-legal, beyond the realm of comfort for a long drive, or lacking storage space for the assorted gear one needs for a long road trip. In addition, certain vehicles have transfer cases that prohibit towing due to lubrication problems within the cases. There are good reasons to tow with a trailer. Also, we would much rather have braking control of 5,000 pounds of trailered rig going down a mountain grade than 4,000 pounds of dead towed weight pushing forward.

Backing up with a flat-towed rig is pretty much impossible after a few feet, due to the built-in caster design of a front steering axle. The caster angle is designed to keep the front wheels going straight when the rig moves forward. When it goes backward—especially when it’s pushed that way—the wheels tend to go to full steering lock to one side or the other, depending on the initial angle.

Another strike against flat-towing your 4x4 occurs when a slow leak in the back tire occurs, because the towed rig has a clutch-type locking differential. The difference in tire height will quickly burn up the differential’s clutches as they try to compensate for the difference in wheel speed. With a true locking differential, axle strain and tire wear will be quite high. An even scarier experience is when the towed rig has an instant flat or blowout from road debris. Sure, you can get a flat on a trailer tire just as easily, but with axles and tires close together, the handling (or should we say the ill-handling) effect is not as pronounced.

Perhaps a more important reason to trailer your rig (although we don’t like to talk about this topic too much) is explained by the word breakage. Sometimes trail fixes and emergency repairs will let you limp back to the pavement, but it won’t be safe or practical for the long flat-tow home. Any number of things can absolutely prevent you from driving the rig home, such as an auto trans slipping, a blown clutch, a broken transmission, or a bent axlehousing.

Now that we’ve convinced you that trailer ownership is right for you, let’s talk about trailers in general.

There are many trailer models available, from simple flatbeds to luxuriously enclosed units. They come in everything from light-duty bumper-pull versions to max-pull fifth-wheel hitches. Some people even modify semi trailers and tractors as camping and Jeep-hauling rigs. Open flatbed trailers offer the versatility of carrying a vehicle, being used to haul firewood and lumber, and helping your mother-in-law move. You can bolt on a large storage box to lock up tie-down straps and extra vehicle parts. A fully enclosed trailer not only offers weather protection, but it protects against your parts and accessories growing legs and walking off. No matter what the choice, there are many issues to consider, not the least of which is braking.

BRAKING

While surge brakes may be OK for a rental fleet and offer trailer-braking ability without the need to wire a controller, an in-cab remote control offers the advantage of applying the trailer’s brakes as needed. Using the trailer brakes alone is the fastest way to straighten it out if it starts to whip or fishtail. Brakes should be on both axles. If it takes two sets of wheels to carry the load, then it should take two sets of brakes to stop the load. A tandem-axle trailer should have brakes on both axles that are sized according to the trailer’s stated GVWC (gross vehicle weight capacity).

BALANCE

Likewise, load balance is important. The rule here is 10 percent minimum, and 15 percent is better. What we’re referring to is that a minimum of 10 percent of the total weight should be on the trailer’s tongue or tow rig’s hitch. This is the secret for a good, straight pull. For example, if your trailer and cargo weigh 6,000 pounds total, then at least 600 of that should be at the trailer’s tongue. Generally speaking, if you drive a Jeep onto the trailer, it should be just about centered over both axles. The engine weight up front will most likely offset the equal balance and put enough weight forward. It may take a couple of tries to figure out the trailer handling and how level the tow rig sits. Once the location is figured out, be sure to mark the spot for future reference, in case you forget it.

Several hitch manufacturers make what is referred to as a sway controller. This is an adjustable friction bar that limits a trailer’s whipping motion. It’s not a substitute for an improperly loaded trailer, but it helps to control unwanted sway on rutted roads and from passing semis.

WEIGHT

Hitch weight often exceeds the capacity of a tow rig’s rear springs. While the rear suspension could be increased with larger coils or more leaves, there are easier ways to do it, and they don’t affect ride height or ride quality when the trailer is not hitched. Air-suspension helpers can be added between the axle and the frame. These airbags can be inflated as needed to keep the vehicle level. There is also a great item called an equalizing hitch. It uses special torsion bars that attach to the tow vehicle’s hitch and the frame of the trailer in such a way that weight is transferred off the ball and to the front wheels of the tow vehicle and the trailer’s axle. Be careful not to exceed the axle capacity or towing capacity of the towing vehicle.

LOADING

When you load your vehicle onto the trailer, a lot of leverage is exerted on the rear of the trailer and transferred to the front. It is not uncommon for a trailer to bend in the middle on either side of the spring hangers. To alleviate that, jackstands or wood blocks can be placed at the rear. Even better is a drop-down or swing-down jackstand mounted to the trailer frame. Jacks save a lot of wear and tear on the trailer and on the tow vehicle.

TIRES

Trailer tires should match the capacity of the trailer. Passenger-car/light-truck tires will work as trailer tires, but they aren’t recommended. To get the necessary load capacity using a tire that fits within the confines of the trailer’s wheel opening, a special trailer tire should be used. When was the last time you saw passenger-car 225/75x15 tires in a “D” load range? Trailer tires are specially designed for trailer use and are marked ST instead of P or LT. Trailer-tire manufacturers address sidewall loading and straight-line stability. The proper load-carrying capacity and condition of the tire is very important. A blowout can turn a well-planned trip into a disaster.

As a reminder, we usually mark the necessary tire pressure, lug-nut torque, and the last time the wheel bearings were repacked on the trailer fender. Whenever we stop for gas, we take a quick walk around the trailer to check the hitch, lights, and tie-downs, and to put our hands on each trailer tire and hub. A temperature difference between any of the tires is a quick indication of low pressure or a wheel bearing that needs service.

TIE-DOWNS

The last thing that you want to address is tying down your rig. You can use chains and chain binders or webbing with ratchet straps. Just be sure that whatever you use, it is up to the job. A 4,000-pound vehicle can exert a lot more than 4,000 pounds of energy in an emergency stopping situation. Each tie-down should have at least a 10,000-pound rating. If they’re properly sized for the job, chains last a very long time, and weather has little effect on them. Any damage can be spotted easily. The downfall is that chains are heavy and bulky, and in time, they’ll acquire a coat of rust. Straps made of polyester webbing are lightweight, easy to handle, and take up very little storage space. They are more prone to wear from sunlight, weather conditions, and abrasion, but often, the advantages outweigh the disadvantages.

Vehicles must be tied down in both the front and rear, in such a manner to prevent any front-to-rear or side-to-side movement. Crossing the tie-downs from one side to the other is the preferred method if you can do it without causing any unequal pull or rubbing on a truck part. It doesn’t do any good to use a 10,000-pound tie-down strap if your tie-down trailer connection is only good for 5,000. Connect your vehicle to the axlehousing or lower suspension member. You do not want to use the frame and pull down on the suspension. A rumor has floated around for years that you should keep the suspension from moving so you don’t wear out the shocks with constant up-and-down movement. Phooey. First, the tie-downs would have to be pretty darn tight to prevent any suspension movement. Second, even when you think the straps are super-tight, there will still be some movement, which puts a shock loading on the tie-down components. You’ll have a lot less suspension movement when you trailer rather than drive, because the trailer suspension takes the brunt of the road shock.

In the interest of balance, there is a downside to trailer ownership. Not only do you have the initial expense, but it requires yearly license fees and insurance, a place to park, a designated towing vehicle, and worst of all, there’ll be people who want to borrow it.

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