Trailering is all about weight. Too much overall, or too much in certain areas, can turn what should be a pleasant towing experience into your worst nightmare. Knowing your rig's weight limits and operating within them is crucial to successful towing.

But it goes beyond just knowing the maximum tow rating of your vehicle. Your rig may be rated by the manufacturer to tow up to, say, 7,500 pounds or more. But you could actually be voiding that manufacturer's warranty if you're towing more than 5,000 pounds. Here's why.

The difference lies in the terms "weight carrying" and "weight distributing." Most tow vehicles actually come with two towing capacities. The advertised rating is the one published in the automaker's manual as "maximum towing or (trailering) capacity." It takes into consideration the engine size, axle ratio, suspension and other factors in arriving at that number. And when equipped with the proper towing components, that's what the vehicle can safely tow.

In almost all cases, however, any stock tow vehicle rated to tow more than 5,000 pounds requires the use of a weight-distributing hitch. Without that special piece of equipment, the towing capacity is generally limited to 5,000 pounds, even if the published maximum towing capacity is considerably greater. To determine if this is the case with your tow vehicle, you can often find a sticker on your receiver hitch that tells you. You'll see one rating for "weight carrying," which is usually 5,000 pounds, and another for "weight distributing," which bears a higher towing capacity. So for you to safely tow the higher capacity, you need a weight-distributing hitch.

A weight-carrying hitch is designed to carry the entire trailer tongue weight at the hitch connection. It consists of the traditional single hitch-ball attachment. Weight-carrying hitches are used in light-duty applications.

A weight-distributing hitch, however, is designed to distribute the tongue weight over all axles of both the tow vehicle and trailer. This weight distribution is accomplished by using a set of spring bars to apply leverage between the tow vehicle and the trailer. Weight-distributing hitches can handle much greater trailer and tongue weights. Therefore, most production tow vehicles with a maximum towing capacity surpassing 5,000 pounds mandate the use of a weight-distributing hitch.

Basically, a weight-distributing hitch comprises a frame-mounted receiver platform and spring bars that attach to sockets in a special ball-mount unit on one end and to the trailer frame on the other end.

Lifting the spring bars at the trailer end transfers most of the tongue weight to the tow vehicle's axles, with the balance going to the trailer axle(s), thereby evening out the towed load. You can adjust this distribution by how far up you lift and attach the spring bars to the trailer frame.

The analogy often used to explain this leverage principle is that of wheelbarrow handles. When you lift the handles, or spring bars in this case, you transfer much of the load force, or weight, forward, rather than holding the handles up. However, the spring bars are fastened to the trailer either with chains and brackets, or pre-drilled brackets with bolts.

In addition to distributing tongue weight, they act as springs to keep constant pressure on the hitch. Spring bars come with varying degrees of tension built in, so be sure to purchase ones specific to your trailered weight. Most weight-distributing hitches also feature adjustable hitch balls that move vertically to obtain the correct height and can be tilted horizontally to keep things level.

While assembling and adjusting a weight-distributing hitch may appear somewhat daunting initially, after you've done it a couple of times the process becomes quick and simple. More importantly, however, it greatly enhances safety.

Aside from the increased towing capacity afforded by a weight-distributing hitch, there are other weight-equalizing benefits. Nonetheless, a great number of people who tow weights more than 5,000 pounds do not use weight-distributing hitches even though the tow vehicle manufacturer requires it.

These individuals are usually pretty noticeable. Often their tow vehicle and trailer sags at the hitch point. This not only looks bad, it is bad. It indicates too much tongue weight. This excessive downward force on the rear of the tow vehicle often produces trailer sway, which can lead to loss of control.

Furthermore, if there's too much weight at the tongue, the downward pressure at the rear simultaneously tends to lift the tow vehicle's front. This can adversely affect steering because the front wheels have diminished traction.

That's obviously not good, especially on slick roads. It also causes the angle of the headlights to point more skyward. In addition to aggravating drivers of oncoming traffic who think you're using your high beams, it decreases your road vision.

Utilizing a weight-distributing hitch can alleviate all of these problems. Some units even incorporate sway bars for added control.

So, with the benefits of increased towing capacity and safer towing conditions, are there any negatives to using a weight-distributing hitch? Yes. Cost is one. A weight-distributing hitch may run you a few hundred dollars more. They also take additional time to hook up, although this is minimal once you perform the task a few times.

When driving, you'll need to make wider turns, so plan accordingly. Also, not all weight-distributing hitches are designed to work well with surge brakes, so be sure you purchase one that does. (Boat trailers generally use surge brakes in lieu of electric brakes due to the water environment they're used in.)

Some hitch models require special adapters or spring bars to be set at an angle to allow trailer coupler movement for proper surge brake operation. If it isn't working properly, you'll experience longer stopping distances because your tow vehicle brakes are doing all the work.

On the other hand, if the coupler doesn't fully release, the trailer brakes will drag, overheat and possibly fail in time. Check with both the trailer manufacturer and hitch manufacturer to ensure you get a unit designed to operate with surge brakes.

In some cases you may find it advantageous to detach the spring bars when launching and retrieving a boat on steep or slippery launch ramps. If your tow vehicle features rear-wheel drive, you may want as much weight on the rear axle as possible for added traction. In that case, the lifting action of the spring bars to redistribute weight evenly to all axles may be a hindrance. Detaching them only takes a minute or so.

All factors considered, the benefits of a weight-distributing hitch far outweigh the disadvantages in most applications. Towing capacity is increased, and you'll likely see dramatic improvement in steering control and braking ability. So if you've had cold feet, this boating season may be the perfect time for you to get hitched.