101 Trailer Sales Trailer Towing Information


Hitch systems, towing packages, tongue weight, and driving permits—there’s

a lot more to towing a trailer than just hitching up and taking off down the road. This


tutorial provides general information and tips hat can help you make safe decisions


when purchasing and driving a tow vehicle and trailer for noncommercial, personal use.


It covers the following topics:


How the size and weight of a trailer affect the selection of a tow vehicle


Things to consider if you already have a tow vehicle


The importance of trailer manufacturers’ tow ratings


How to measure the weight of a trailer


The hitching, braking, and wiring systems that connect tow vehicles with trailers


Tire safety


Proper loading and weight distribution of cargo and equipment


State and local requirements for towing a trailer


A pre-departure checklist


Safety tips for driving with a trailer


Safety tips for maintaining a tow vehicle and trailer


Most SUVs, pickup trucks, vans, minivans, and passenger cars can be equipped to tow a trailer. However, the selection of an appropriate tow vehicle and the proper


equipment to tow a trailer depends on the type of trailer, its size and weight, and the


amount of weight being towed. There are numerous types of trailers, but in general they


fall into four categories: flatbed or open trailers, boat trailers, enclosed trailers, and


recreational vehicle trailers (including travel trailers, fifth-wheel trailers, and folding


camping trailers).  Check the owner’s manual and review the manufacturer’s guide to


see if the vehicle you plan to buy can tow a trailer. After you have reviewed the vehicle


capabilities, you also must investigate the capabilities of compatible hitch systems for


the vehicle. This is especially important if you plan to purchase a hitch from a source


other than the vehicle manufacturer.  You may find that vehicle manufacturers offer


specially designed towing packages that define the equipment necessary to tow different


types of trailers depending on their fully loaded weight and size. A towing package may


include a heavyduty radiator, battery, flasher system, alternator, suspension, and


brakes, as well as an engine-oil cooler, transmission-oil cooler, wiring harness, specific


axle ratio, and special wheels and tires.  Towing packages also may include the trailer


hitch receiver, which is mounted to the tow vehicle, but towing packages rarely include


the draw bar, or ball mount and hitch ball. The draw bar is a separate assembly on


which the hitch ball is mounted. The draw bar then slides into the hitch receiver on the


tow vehicle and is secured with a locking pin. The front part of the trailer that hitches to


the tow vehicle is referred to as the tongue. At the end of the tongue is a coupler into


which the hitch ball is inserted and secured.  A manufacturer may offer different towing


packages to safely tow various sizes and types of trailers. Towing packages indicate


both equipment that must be installed on your tow vehicle and equipment that is optional


or recommended. For example, not all trailers require the tow vehicle to be equipped


with extended side-view mirrors. But extended side-view mirrors. But is wider than your


tow vehicle, you will need extended side-view mirrors to see rear- and


sideapproaching traffic.


If you already have a tow vehicle, look up its tow rating—size, maximum loaded weight, and maximum tongue weight of a trailer that the tow vehicle is capable of towing.


The vehicle owner’s manual contains these specifications.


Most automotive manufacturers and dealerships have towing specification guides with


tow ratings and detailed information if extra equipment is needed to tow a trailer. While


your vehicle may have certain tow ratings, remember you must have a matching hitch


system that can handle the same specifications. To ensure safety, you may have to


install extra towing equipment.


Manufacturers’ Tow Vehicle Ratings


Manufacturers’ tow vehicle ratings address tongue weight as well as the individual,


combined, and fully loaded weights at which a tow vehicle can safely tow a trailer. They


also can be used to guide the selection of brake and hitching systems as well as tow


vehicle tires. Together with the hitch system specifications, these weight considerations


will help you purchase a safe tow vehicle. In general, manufacturers provide tow ratings


for the maximum


• Amount the tow vehicle may weigh when fully

loaded, or gross vehicle weight rating (GVWR).


• Weight a vehicle can tow. This figure may vary depending on the vehicle’s equipment,


Such as a manual or automatic transmission and whether it is equipped with four-wheel




Permissible combined weight of the tow vehicle, trailer, passengers, equipment, fuel,


etc., that the vehicle can handle, or gross combination weight rating (GCWR).


• Weight a single axle can carry, or gross axle weight rating (GAWR).


Measuring the Weight of a Trailer


Some manufacturers provide a “dry” or empty weight for trailers; however, to select a


Proper tow vehicle and hitching system, you must know how much your trailer weighs


fully loaded. For example, if you are towing an open trailer that carries a boat or


motorcycle, the fully loaded weight includes the weight of the trailer with the boat or


motorcycle and any additional items being towed, such as fuel tanks, motors, and safety





Develop a realistic estimate of the total weight of your trailer. The time you spend doing


this and getting properly equipped will save you time and money in preventing


unexpected repairs to your tow vehicle and unanticipated breakdowns while on the road.


In addition to speaking with dealers and other individuals who sell and use trailers, the


best way to know the actual weight of your trailer is to weigh it at a public scale.


Manufacturers consider the loaded weight of a trailer when specifying tongue weight


the amount of the trailer’s weight that presses down on the trailer hitch. Too little tongue


weight can cause the trailer to sway. Too much tongue weight can cause many


problems, including not enough weight on the front wheels of the tow vehicle.


When this occurs, the tow vehicle will be less responsive to steering. A weight-


distributing hitch can remedy this problem by transferring weight to the front axle of the


tow vehicle. Manufacturers also establish the gross axle weight and provide a rating that


denotes the maximum weight a single axle can carry. Knowing these weights will help


you when it is time to load your trailer. Remember that the gross axle weight rating listed


on the tow vehicle’s certification label must not be exceeded.




Tow vehicles and trailers must be compatible with hitching, braking, and wiring systems to ensure safety.


Hitching Systems


The trailer towing industry has developed a classification system that differentiates


hitches according to the amount of weight they can tow. This system addresses tongue


weight and total weight. Keep in mind that within each classification are numerous


hitches made by a variety of manufacturers.

The three most common types of hitches are the weight-carrying hitch, the weight-


distributing (or load equalizer) hitch, and the fifth-wheel hitch, or gooseneck. Weight-


carrying hitches are designed to carry all of the trailer’s tongue weight. Weightdistributing


hitches are used with a receiver hitch and special parts that distribute the tongue weight


among all tow vehicle and trailer axles. Fifth-wheel hitches are designed to mount the


trailer connection in the middle of the truck bed. When purchasing a hitch, use the


recommendations of the manufacturer of the tow vehicle and trailer based on the type


and weight of the trailer. Make sure the hitch has provisions for the connection of safety


chains, which are required by most states. When connected, safety chains should have


some slack to permit sharp turns but should not drag on the road. In addition, they


should cross under the trailer tongue to help prevent the tongue from dropping to the


road in the event the trailer separates from the tow vehicle.


Braking Systems


The selection of a brake system also will depend on your tow vehicle and the type and


fully loaded weight of your trailer. For a trailer with a loaded weight of more than 1,500


pounds, many states require a separate braking system and a breakaway switch,


located on the tongue of the trailer, to activate the trailer brakes in the event the trailer


separates from the tow vehicle. There are two basic types of brake systems designed to


activate the brakes on a trailer:


• Electronically controlled brakes usually provide automatic and manual control for trailer


brakes. They require that the tow vehicle be equipped with a controlling device and


additional wiring for electrical power. These brakes typically have a control box installed


within reach of the driver and can be manually or automatically applied. The control box


may require adjustment or“tuning in” for variations in trailer load


• Surge brakes are independent hydraulic brakes activated by a master cylinder at the


junction of the hitch and trailer tongue. These brakes are not controlled by the hydraulic

fluid in the brake system of the tow vehicle. Note: The hydraulic system of the tow


vehicle should never be directly connected to the hydraulic system of the trailer. These


systems are self-compensating and do not require adjustment for variation in trailer load.


Follow the tow vehicle manufacturer’s recommendations for brake selection. Some


states require braking systems on all axles of the trailer. So, check your state’s


requirements by contacting the motor vehicle administration.


Wiring Systems

Federal law requires trailers to have taillights, brake lights, side marker lights, turn


signals, and side and rear reflectors. Some trailers also have backup lights. To provide


power to these lights, a four-way (or more) connector is hooked into the tow vehicle’s


electrical system. Many tow vehicle manufacturers offer a 7-way connector that may


include an electric brake signal, power supply, and backup lights, in addition to the


typical four functions. Note: You must ensure that the signals on the electrical connector


of the tow vehicle match the electrical connector of the trailer. Because the wiring


systems of many tow vehicles use separate wires for turn signals and stop lights, you


may need to purchase a taillight converter. This converter will combine these wires so


that they can be connected to the trailer lighting system. Most factory-installed towing


packages include a trailer wire harness that will perform this function if required. If you


tow more than one type of trailer, you also may need to purchase an adapter to


accommodate differences in the wiring systems



All your trailer tires should be the same type, size, and construction—do not mix biasbelted and radial tires. In selecting tires for your trailer, buy the size, type, and load


range found on the trailer’s certification label or in the owner’s manual. Keep in mind that


tires have a load rating that indicates the amount of weight they can carry safely. As with


your tow vehicle always maintain proper tire pressure and replace worn tires.

Remember—your tow vehicle tires may require a higher tire pressure for towing,


especially heavy loads.


Your ability to handle and control your tow vehicle and trailer is greatly improved when the cargo is properly loaded and distributed.  Refer to your tow vehicle and trailer


owner’s manuals to find out how to


• Balance weight from side to side


• Distribute cargo weight evenly along the length

of the trailer


• Secure and brace all items to prevent them

from moving during travel


• Adjust the height of the tow vehicle/trailer



• Apply load leveling (weight distributing hitch



Most trailers and tow vehicles should be level (parallel to the ground) during travel.


Check the instructions from your trailer manufacturer to make sure this is correct for your


combination of vehicles.



States and municipalities may require special permits and licenses based on the

size and weight of your trailer, especially if it is over eight feet wide. Some states require


additional equipment for the tow vehicle, such as side- and rear-view mirrors. Inquire at


your local motor vehicle administration to find out what requirements affect you.


If you plan to travel in another state, don’t forget to check its requirements also. For


example, surge brakes may not be legal in some jurisdictions. In addition to licenses and


permits, there may be weight, height, and width limits for using certain roads, bridges,


and tunnels. Also, be aware of restrictions regarding the transport of propane gas and


other volatile gases or fuels in tunnels. And don’t forget to contact your insurance


company to make sure you have the proper coverage.





Before driving, make sure your vehicle maintenance and trailer maintenance are current.


This is very important because towing puts additional stress on the tow vehicle.


Check and correct tire pressure on the tow vehicle and trailer. Make sure the wheel lug


nuts/bolts on the tow vehicle and trailer are tightened to the correct torque. Be sure the


hitch, coupler, draw bar, and other equipment that connect the trailer and the tow vehicle


are properly secured and adjusted. Check that the wiring is properly connected— not


touching the road, but loose enough to make turns without disconnecting or damaging


the wires. Make sure all running lights, brake lights, turn signals, and hazard lights are


working. Verify that the brakes on the tow vehicle and trailer are operating correctly.


Check that all items are securely fastened on and in the trailer. Be sure the trailer jack,


tongue support, and any attached stabilizers are raised and locked in place. Check load


distribution to make sure the tow vehicle and trailer are properly balanced front to back


and side to side. Check side- and rear-view mirrors to make sure you have good


visibility. Check routes and restrictions on bridges and tunnels. Make sure you have


wheel chocks and jack stands.





Take time to practice before driving on main roads and never allow anyone to ride in or


on the trailer. Before you leave, remember to check routes and restrictions on bridges


and tunnels. Consider the following safety tips each time you drive with a trailer.


General Handling


Use the driving gear that the manufacturer recommends for towing. Drive at moderate


speeds. This will place less strain on your tow vehicle and trailer. Trailer instability


(sway) is more likely to occur as speed increases. Avoid sudden stops and starts that


Can cause skidding, sliding, or jackknifing. Avoid sudden steering maneuvers that might


create sway or undue side force on the trailer. Slow down when traveling over bumpy


roads, railroad crossings, and ditches. Make wider turns at curves and corners. Because


your trailer’s wheels are closer to the inside of a turn than the wheels of your tow vehicle,


they are more likely to hit or ride up over curbs. To control swaying caused by air


pressure changes and wind buffeting when larger vehicles pass from either direction,


release the accelerator pedal to slow down and keep a firm grip on the steering wheel.




Allow considerably more distance for stopping. If you have an electric trailer brake


Controller and excessive sway occurs, activate the trailer brake controller by hand. Do


not attempt to control trailer sway by applying the tow vehicle brakes; this will generally


make the sway worse. Always anticipate the need to slow down. To reduce speed, shift


to a lower gear and press the brakes lightly.


Acceleration and Passing


When passing a slower vehicle or changing lanes, signal well in advance and make sure


you allow extra distance to clear the vehicle before you pull back into the lane. Pass on


level terrain with plenty of clearance. Avoid passing on steep upgrades or downgrades.


If necessary, downshift for improved acceleration or speed maintenance. When passing


on narrow roads, be careful not to go onto a soft shoulder. This could cause your trailer


to jackknife or go out of control.


Downgrades and Upgrades


Downshift to assist with braking on downgrades and to add power for climbing hills.


On long downgrades, apply brakes at intervals to keep speed in check. Never leave


brakes on for extended periods of time or they may overheat. Some tow vehicles have

specifically calibrated transmission tow-modes. Be sure to use the tow-mode


recommended by the manufacturer.


Backing Up

Put your hand at the bottom of the steering wheel. To turn left, move your hand left. To


turn right, move your hand right. Back up slowly. Because mirrors cannot provide all of


the visibility you may need when backing up, have someone outside at the rear of the


trailer to guide you whenever possible. Use slight movements of the steering wheel to


adjust direction. Exaggerated movements will cause greater movement of the trailer. If


you have difficulty, pull forward and realign the tow vehicle and trailer and start again.



Try to avoid parking on grades. If possible, have someone outside to guide you as you


park. Once stopped, but before shifting into Park, have someone place blocks on the


downhill side of the trailer wheels. Apply the parking brake, shift into Park, and then


remove your foot from the brake pedal. Following this parking sequence is important


to make sure your vehicle does not become locked in Park because of extra load on the


transmission. For manual transmissions, apply the parking brake and then turn the


vehicle off in either first or reverse gear. When uncoupling a trailer, place blocks at the


front and rear of the trailer tires to ensure that the trailer does not roll away when the


coupling is released. An unbalanced load may cause the tongue to suddenly rotate


upward; therefore, before uncoupling, place jack stands under the rear of the trailer to


prevent injury.




Tow vehicles often have more frequent maintenance requirements, including changes


of engine and transmission oils and filters, lubrication of components, and cooling


system checks. Check your owner’s manual for information on scheduled maintenance


of your tow vehicle and trailer. Here are some additional maintenance suggestions.



Periodic inspection and maintenance of tow vehicle and trailer tires and wheels are


Essential to towing safety, including spare tires. Proper tire pressure affects vehicle


handling and the safety of your tires. You can find the correct tire pressure for your tow


vehicle in the owner’s manual or on the tire information placard. Underinflation reduces


the load-carrying capacity of your tow vehicle or trailer, may cause sway and control


problems, and may result in overheating, causing blowouts or other tire failure.


Overinflation causes premature tire wear and affects the handling characteristics of the


Tow vehicle or trailer.




On a regular basis, have the brakes on both vehicles inspected. Be sure that necessary


adjustments are made and any damaged or worn parts are replaced.




Check the nuts, bolts, and other fasteners to ensure that the hitch remains secured to


the tow vehicle and the coupler remains secured to the vehicle and the coupler remains


secured to the trailer. The connection point may require periodic lubrication to permit


free movement of the coupler to the hitch ball.




Make sure connector-plug prongs and receptacles, lightbulb sockets, wire splices, and


ground connections are clean and shielded from moisture. Lightly coat all electrical


terminal connections with nonconducting (dielectric), light waterproof grease.


Clean the prongs with very fine sandpaper, being careful not to damage the contact


area. Clean the surface deposits in the connector holes. (Make sure the lights are off to


prevent blowing a fuse.) Try to clean off only the deposits and lubricate lightly with


dielectric, light waterproof grease.