Davis Trailer World and Country Mall
Davis' Trailer World Home
Contact Davis Trailer World
Upcoming Events
Ask the Expert
Used Trailers
Trailer Accessories
Truck Caps and Truck Accessories
Truck Beds
Specialty Items
Western/Work Wear
Trailer Parts and Trailer Services
Davis Trailer World Online Shopping
Trailer Brakes
Rolling Delight Wagons
View Cart
Finance Options
Safety Towing Tips & Terminology
Davis Trailer World Policies
About Us
Sign Up with Davis Trailer World
Google Plus


Safety Towing Tips & Terminology

Things that you should be familiar with before & while towing a trailer

Gross Vehicle Weight (GVW): is not a rating, it is the actual maximum weight of the tow vehicle when it is fully loaded including all options, cargo, personal belongings, food, water and LP gas.

Gross Combined Weight Rating (GCWR): is the maximum permissible combined weight of the tow vehicle and the trailer together when they are fully loaded for travel.

Unlaiden / Unloaded Vehicle Weight or Dry Weight (UVW) or (DW): is the actual weight of the tow vehicle or trailer as built at the factory. The UVW does not include passengers, cargo, dealer installed options, personal belongings, water, or LP gas.

Vehicle Tow Rating: Make sure your tow vehicle is capable of towing the intended trailer or accessory. The trailer or accessory and the vehicle work together in determining the maximum capacity. In no case should the GTW or TW exceed the towing capacity of your vehicle, your trailer or your accessory. Find this information in the vehicle owners manual or www.trailerlife.com, look under “tow ratings”.

Gross Vehicle Weight Rating (GVWR): Is the maximum weight of the fully loaded trailer, as published on the Certification / VIN label. Actual weight determined by weighing trailer on a public scale, without being attached to the towing vehicle.

Hitch Weight: The downward force exerted on the hitch ball by the trailer coupler.

Maximum loaded vehicle weight - The sum of curb weight, accessory weight, vehicle capacity weight, and production options weight.

Gross Axle Weight Rating (GAWR): The maximum weight that any axle can support, as published on the Certification / VIN label on the front left side of the trailer. Actual weight determined by weighing each axle on a public scale, with the trailer attached to the towing vehicle.

Both tire and VIN certification labels are permanently attached to the trailer near the left front corner or on the tongue of the trailer.

Both Tire And VIN Certification Labels are permanently attached to your tow vehicle on the drivers door panel or on the column behind drivers door. See owners manual for further details or specifications.

Understanding Tires:

Example: ST205/75R15

  • ST - Trailer Tires only
  • LT - Light Trucks or Trailers
  • P - Passenger Tires
  • Next 3 Digits - give the width in millimeters of the tire from sidewall edge to sidewall edge
  • Next 2 Digits - give the aspect ratio, the tires ratio of height to width
    • R - Radials
    • D - Bias  Ply
  • Last 2 Digits - gives the wheel or rim diameter in inches

Bias ply tire: A pneumatic tire in which the ply cords that extend to the beads are laid at alternate angles substantially less than 90 degrees to the centerline of the tread.

Example - ST205/75D15

Radial ply tire: A pneumatic tire in which the ply cords that extend to the beads are laid at substantially 90 degrees to the centerline of the tread.

Example – ST205/75R15

Load rating: The maximum load that a tire is rated to carry for a given inflation pressure.

Tire Ply: Is the number of layers of rubber coated fabric in the tire.

Load Range: (Load range = 2ply/ Letter) Letters are used to identify a given size tire with its load and inflation limits, when used in a specific type of service.

Example: Load Range D tire = 8 ply or Load Range C = 6 ply

Tires/ Tire Pressure: - Always use the proper size tire/weight rating for the trailer  & maintain manufacturers recommended tire pressure.

Recommended inflation pressure is provided by the vehicle manufacturer on the tire sidewall and on the Certification / VIN tag, which is usually located at the front left side of the trailer.

Hitch Terminology:

GTW = Gross Trailer Weight - the weight of the trailer fully loaded
TW=Tongue Weight-The downward force that is exerted on the hitch ball by the coupler.        
        The tongue weight will vary depending on where the load ia positioned                                           in relationship to the trailer axle(s).
WC = Weight Carrying - The total weight of both the trailer and cargo inside.                            Never exceed the weight capacity of your trailer hitch. This applies to loads without a weight distribution system
WD = Weight Distributing - Used to balance the weight of the cargo between the front and rear wheels throughout the trailer, alowing for better steering, braking, and level riding. Not to be used on class 1 or 2 receivers, or with surgebrakes.                                                                                  

To select the right hitch for your vehicle:

1. Check the towing capacity of you tow vehicle.
2. Determine the gross trailer weight (GTW) of your tow item.
3. Select the class of hitch rated for you vehicle.

NOTE: Never tow a trailer with a gross trailer weight greater than the vehicle manufacture's rating. It could cause damage to the vehicle's engine transmission and frame. And could void any manufacture's warranties. A higher class of hitch DOES NOT increase the vehicle's tow capacity.

Vehicle Type >>

Compact Cars Mid-Size Cars Full-Size Cars
& Vans
Full-size Trucks,
Vans & SUVs
Hitch Class Rating
Class I
WC GTW - Up to 2,000 lbs.
WC TW - Up to 200lbs.
Light Duty Light Duty Light Duty Light Duty
Class II
WC GTW - Up to 3,500 lbs.
WC TW - Up to 350lbs.
  Medium Duty Medium Duty Medium Duty
Class III
WC GTW - Up to 5,000 lbs.
WC TW - Up to 500lbs.
    Heavy Duty Heavy Duty
Class IV
WC GTW - Up to 7,500 lbs.
WC TW - Up to 750lbs.
WD GTW - Up to 12,000 lbs
WD TW - Up to 1,200 lbs
    Heavy Duty Heavy Duty
Class V
WC GTW - Up to 12,000 lbs.
WC TW - Up to 120lbs.
WD GTW - Up to 14,000 lbs
WD TW - Up to 1,400 lbs
      Extra Heavy Duty

Hitch Ball:

Always be sure that the ball size & trailer coupler size are matched, and weight rating is sufficient for the trailer being towed. 


Weight Distributing Hitch Systems:

“also referred to as sway bars, leveling bars, etc.” are designed to increase the capacity of the towing system when added to a Class III, IV or V trailer hitch. The idea is to distribute the load of the trailer evenly to the entire tow vehicle and trailer wheels. To accomplish this, spring bars are used to absorb load and level the trailer. This offers a more level ride, improved steering and increased braking control, all the while enhancing towing safety.


Trunnion Style Weight Distribution Hitch is the most common. (as shown above)

What is included with a Weight Distribution Hitch?  

    1. Adjustable Weight
        Distribution Shank
    2. Spring Bars
    3. Adjustable Ball Mount
    4. Hook-up Brackets
    5. Hook-up Chains
    6. Pin & Clip (not pictured)
Note: Weight Distribution Hitches DO NOT include hitch ball Recommend 2 5/16” A-6 or 2” A-90 Trailer Ball

Check level of the trailer:

Always try to maintain the trailer coupler & vehicle hitch in a level position to help minimize fishtailing. Fishtailing refers to the erratic side to side movement of the trailer. It is important when towing a trailer whether it is a bumper pull or a gooseneck style to achieve a level position when loaded. The reason for this is that you want to have an even weight displacement on the axles. For example, if the trailer is to high in the front excessive stress may be applied to the rear axle and/or if the front of the trailer is to low the front axle may become stressed. In extreme cases this can lead to axle failure due to overloading. When hitching up to an unloaded trailer we recommend having the trailer set up slightly higher in the front to allow for settling once the trailer is loaded. Further adjustment of trailer front height may be required as load conditions change.

Cargo Placement:

Always keep your load balanced front/back & side/side as not to have too much or too little weight on the tongue. The tongue weight should never exceed 10% of the Gross Towing Weight.

Load Securement:

Make sure that all items are properly secured inside & on the trailer. The driver is responsible for anything that may separate from the trailer.

Refer to: www.fmcsa.dot.gov/rules-regulations

Axle Types:

Torflex® axles are designed as a completely self-contained axle and suspension system. This trailing arm type torsion axle employs natural rubber cords supporting heat treated inner bars of solid, medium carbon steel. Press-fitted and welded to the ends of this independently floating bar are high strength steel torsion arm/spindle assemblies. These arms can be specified to a range of starting angles, which allow the designer to tailor the running height of the vehicle.

Torsion Axle

Leaf Spring axles utilize high strength steel spindles welded to high strength tubing to form an axle beam. The spindles are usually available in either a straight or drop design to help designers establish the desired frame height or ground clearance. Leaf springs are attached to the axle using u-bolts and can be positioned either under or over the tube. Use under mounted springs (underslung) to lower the frame height and over mounted springs (overslung) to raise the frame height.

Spring Axle

Ball Mounts:

The ball mount is placed inside the opening of the receiver hitch which is mounted to the vehicle. Make sure a hitch pin is properly securing the ball mount to the receiver hitch before you begin towing. Ball mounts are grouped into three (3) styles.

Style Type 1
Used for vehicle and trailer equally level towing
Style Type 2
Used for vehicle and trailer NOT equally level towing
Style Type 3
Straight Cut

Trailer Ball:

Trailer BallThe most important connection from the hitch to the trailer.

There are many factors that determine the correct hitch ball:

  • Most important is the hitch ball's gross trailer weight rating
  • The mounting platform must be at least 3/8" think
  • The hole diameter must not be more than 1/16" larger than the threaded shank
  • Every time you tow, check the nut and lock washer to make sure they are fastened securely


CouplerThe component that is placed over the trailer ball to connect the vehicle to the trailer. Be sure that the coupler size matches the size of the hitch ball and that the coupler handle is securely fastened. To determine what size hitch ball you need for your application you will need to know the size of the coupler that is on the trailer. Be sure your coupler is properly adjusted to the ball you are using.

Pin & ClipPin & Clip:

For securing all ball mounts to receiver style hitches. Hitch Locks protect against ball mount theft.

Safety Chains: Must always be cross hooked

Safety chains are a requirement and should be crossed under the tongue of the trailer so that the tongue will not drop to the road if it becomes separated form the hitch. Always leave enough slack so you can turn. Never allow the safety chains to drag on the ground and never attach the chains to the bumper.

Trailer Classification: Safety Chain Breaking Force - Minimum
Class 1: 2,000 lbs. (8.9 kN)
Class 2: 3,500 lbs. (15.6 kN)
Class 3: 5,000 lbs. (22.2 kN)

The strength rating of each length of safety chain or its equivalent and its attachments shall be equal to or exceed in minimum breaking force the GVWR (Gross Vehicle Weight Rating) of the trailer.


   Every time you tow, be sure to check that all components are working properly -

                trailer lights, electrical brakes, break-away systems.




Davis' Trailer World & Country Mall
1640 Main Street, York, NY 14592-0260
585-538-6640 | 1-800-693-2184


Proud Member of the

Serving the Western New York Area and Beyond
Including Rochester, Buffalo, Syracuse, Binghamton, and Elmira

Davis Trailer World Home | Contact Us | Site Map | Government | Policies
Trailers | Used Trailers | Truck & Trailer Accessories | Truck Beds | Trailer Parts & Service
Outdoor Products | Western Wear & Work Wear | Safety Towing Tips & Terminology

Note: Some photos displayed have optional features that are not standard.
© 2014 Davis' Trailer World & Country Mall

PayPal Acceptance Mark