A closer look at a typical...
A closer look at a typical Vehicle ID sticker shows that it has the VIN number for your vehicle, plus the gross axle weight rating for each axle, plus the gross vehicle weight rating, given certain wheels, certain tires, at a certain tire pressure.
Problem #4:
Identical-Appearing Trucks May Have Very Different Towing Capacities
Here's another example of how actual tow capacities can be tricky to guarantee. A Dodge Dakota SLT Quad Cab 4x4 with a 5-foot bed, five-speed automatic, 545RFE automatic and the 4.7-liter V-8 engine with 3.92:1 axle ratio is rated to tow 6,850 pounds, and up to 11,700 pounds in gross combined weight. Yet the exact same truck, with 3.55:1 axle gears, will be rated to tow only 5,650 pounds, and 10,500 pounds total. Both trucks have the same axles, the same curb weight, the exact same equipment packages. But they have different gear ratios. Just altering one item on the spec sheet--an item you can't see--changes the ratings by 1,200 pounds of towing capacity.
What to do:
Your door sticker may not identify the gear set in your axle(s). Get under your truck and find the axle tag or housing stamp. Use that to compare with the info charted in your owner's manual.
Problem #5:
State Laws
The definition of "properly equipped" is also set by state law, which governs trailer length, weight, brake standards, width, height and towing speeds, among other things. You might talk with your trailer vendor to make sure you are in compliance when you buy your trailer. Problem is, even if you are within the laws of your home state, you might be a sitting duck the next state over.
As a general rule, the maximum trailer height is 13 feet, 6 inches, but 17 states do permit 14-foot height. One state, Nebraska, allows trailers to be 14 feet, 6 inches.
In most places the maximum trailer width is 8 feet, 6 inches, but in three states, it is 8 feet and in one state, Hawaii, it is OK to be 9 feet wide.
Maximum trailer length ranges anywhere from 40 feet (13 states) to 53 feet (5 states) and everywhere in between. In 12 states, there is no maximum length at all.
Maximum combined rig length varies from 85 feet in Wyoming to 55 feet in Maryland, and ranges widely in between.
Maximum towing speeds can be as high as 75 mph (8 states) or as low as 45mph, as in Alaska.
There seems to be no rhyme or reason to this patchwork of regulations. In California you are required to tow at 55 mph with trailer brakes on your 1,500-pound, 14-foot tall, eight-and-a-half-foot wide trailer, with 65 feet as your maximum overall length. When you get to Arizona, the same rig is illegally wide by six inches, illegally tall by six inches, but you can go 70 mph.
In Massachusetts, it is fine to tow a 40-foot trailer weighing 10,000 pounds at 65 mph without trailer brakes . . . but if you cross the border into Maine, and your trailer weighs 3,000 pounds, you better have trailer brakes. In Tennessee, trailer brakes are required if your trailer weighs 1,500 pounds, in Utah at 2,000, in Oklahoma at 3,000, in Delaware at 4,000, in Alaska at 5,000 pounds, and in Massachusetts, it's a truly optimistic 10,000 pounds.
What to Do:
You'll have to check the regulations in your state, and the states you might tow through. Just Google up "Towing Regulations" and you'll find any number of links that will chart out all the info you need. It may take a trip back to the trailer dealer to get set up to comply in neighboring states, but it might save you a couple of tickets, and keep your insurance company on your side if the worst should happen.
 A standard receiver hitch...  A standard receiver hitch comes in two configurations, Class 3 (2-inch receiver) and Class 4 (2.5-inch receiver). Your hitch and drawbar must match. It is possible to adapt a 2.5-inch receiver to a 2-inch drawbar, but it will significantly reduce the weight you can tow. This Class 3 receiver, on this 1/2-ton truck with this type of trailer, is good up to 6,000 pounds. |  Your owner's manual will chart...  Your owner's manual will chart all the different towing and hauling capacities, based on equipment, body type, engine, transmission, axle ratio, and hitch type. The permutations can be a bit complex. There might be separate charts for Gross Combined Weight Rating, another page for gross trailer weight (GTW) with tongue weight for every given hitch type, and yet another chart for maximum hauling weights (GVWR). Just be sure you are looking at the right numbers. Usually the same information is available on the web sites of the manufacturers, such as www.ford.com. |  The type of hitch you use...  The type of hitch you use makes a huge difference in towing capacity. This is a weight-distributing hitch. WD hitches are not supplied by the OE manufacturer, but always specified as necessary for higher towing capacity. It consists of a system of draw bar, matched hitch ball, spring bars and snap-up brackets. It distributes the tongue load between the truck and trailer, practically doubling the amount you can tow. For even higher towing capacities, a bed-mounted gooseneck hitch can tow a trailer configured as a fifth wheel. It's not uncommon to see towing ratings of fifth-wheel trailers as high as 25,000 pounds and more. With just a regular, weight-carrying hitch, the maximum trailer weight for the same 1-ton pickup might be 8,000 pounds or less. |
Tongue load is difficult to...
Tongue load is difficult to measure accurately, but you can get a rough idea by noticing how level the tow vehicle sits. Here, we see a heavily loaded truck and trailer that appears to be well balanced, front to rear. To be more precise, measure the distance from wheel well to ground, before and after hooking up the trailer, to see how the trailer's weight alters the tow vehicle stance.
Problem #6:
Tongue Weight
Tongue weight is actually the hardest requirement to address, and one of the most important to get right. Too much tongue weight and you overload the rear axle, maybe blow a rear tire or melt down the axle gears. With the front end pointing to the sky, steering and braking will be sketchy. On the other hand, with too little tongue weight, the trailer will haul up on the rear axle of your truck, so you'll overload the front axle and front brakes, and have almost no rear brake effect at all. And the hitch could come off the ball with any bounce.
As a general rule, manufacturers specify that tongue weight be 10 to 15 percent of the total load. If your trailer weighs 6,000 pounds, tongue weight should be around 600 or maybe 750 pounds. This is too much to check using a bathroom scale, and difficult to accurately check at the truck scales.
What To Do:
Your most practical solution is to go by how level the tow vehicle sits. You can do this visually, or you can actually measure from the top of the wheelwells to the ground, loaded and unloaded. If you find the tow truck sitting at an unlevel attitude, move cargo around until the combination is leveled out. You want all the tires to be handling their part of the load. Otherwise, better hope braking and steering won't be necessary when that kid on a bicycle crosses the road in front of you.
Trailer tires are rated by...
Trailer tires are rated by miles, not by tread wear. Usually 5,000 miles is the limit, so they should be replaced even if the tire appears to have good tread, or whenever cracks appear on the sidewall. To reduce the tendency for sidewall cracking if your trailer sits during the week, make sure the trailer rests with tires at full pressure on level ground. For long-term storage, put the trailer on blocks, and reduce inflation pressure.
Problem #7:
Replacement Tires
Most of us have reason to add bigger wheels and/or tires to our tow rigs, and some of us have been known to run tire pressures at somewhat less than the maximum, for comfort and traction. Unfortunately, that compromises the factory tow ratings. Aftermarket wheels are generally not Department of Transportation (DOT) approved, and may not be perfectly matched to the tires you have chosen. Bigger tires, especially those with a more aggressive tread, almost always do not have the same load rating as the stock tires. When you try to tow with them, you have created a new weak link.
What To Do:
Before you tow on that set of new rubber, compare the load ratings versus the tire specified in your owner's manual. If your new tires can't carry the same load, reduce your towing/hauling weight accordingly. Be especially cautious when replacing dually tires, as there are not many combinations that keep the factory load ratings intact.
Check the sidewalls to see what the difference is, and do be certain you have the tire pressure maxed out to the number on the sidewall using that good tire gauge you always carry.