Q: Are the tires manufactured and used on trailers different than the tires on my car or truck?

A: Yes. There are some tires that are specially designed to be used on trailers. These tires include the letters "ST" in the size specification that is listed on the sidewall. The "ST" stands for "special trailer." ST trailer-designated tires have a stronger sidewall than an automobile or truck tire and can handle higher air pressures and higher loads.

Q: Is it important that I keep the correct amount of air pressure in my trailer tires?

A: Yes. Trailer tires should be inflated to their maximum air pressure. The value for the maximum air pressure will be listed on the tire's sidewall, along with the value for the maximum load. These values will designate the maximum load at a maximum psi. For example, if the tire is rated at 1,610 lbs. maximum at 65 psi, the tire can carry 1,610 lbs. of weight if the air pressure is at the maximum of 65 psi. At the maximum air pressure, the tires will perform and wear best, thus helping you achieve the best gas mileage. If a trailer tire is inflated to a lower air pressure than the maximum, the amount of weight that the tire can carry will be reduced. If a heavier load is put on the trailer tire than what is recommended for that air pressure, the sidewall of the tire could overheat and cause the tire to fail. It is important that you always inflate your tires when they are cold. It is also important to remember that if a tire is overinflated, it will wear more in the center of the tread, completely around the tire. If a tire is underinflated, it will wear on the outside edges of the tread, completely around the tire. Maintaining the correct air pressure in your trailer tires can substantially increase tire longevity.

Q: What is the significance of ply rating and load range when I am choosing the correct tire for my trailer?

A: The load range branded on a tire’s sidewall identifies how much load the tire is designed to carry at its industry-specified pressure. Trailer tires feature named load ranges that ascend in alphabetical order (B, C, D, E, F, G, H). Letters further along the alphabet identify stronger tires that can withstand higher inflation pressures and carry heavier loads (for example, a D rating is stronger than a C rating). Many years ago, the “ply” was a literal numeric description of the number of layers of body ply layers of cotton fabric used in a given tire. Advanced technology and development of higher strength nylon cords allowed the tire manufacturer to use fewer body plies, yet maintain strength of the tire body. Today`s “ply ratings” do not count the actual number of body ply layers used to make up the tire’s internal structure, but indicate an equivalent strength compared to early cotton fabric bias ply tires. Most modern tires have only one or two body plies, and trailer/truck tires, even those with heavy-duty ratings (10-, 12- or 14-ply rated), actually have only two or three fabric plies, or one steel body ply. Listed below are today’s common tire load ranges and the equivalent “ply rating” of each: Load Range B = 4 ply rating Load Range C = 6 ply rating Load Range D = 8 ply rating Load range E = 10 ply rating Load Range F = 12 ply rating Load Range G = 14 ply rating Load Range H = 16 ply rating

Q: Is there a designated speed rating for ST Tires?

A: Yes. Special trailer tires are usually rated to operate at a maximum speed of 65 mph. If you exceed 65 mph, the tire may overheat and fail. If a tire is rated to run at a higher speed than 65 mph, this information will be listed on the trailer's sidewall.

Q: Is it important that I use “matching tires” when hauling and using my trailer?

A: Yes. You should always use tires of the same size, load range, and construction on a trailer. If your tires don't match, you could experience problems of overloading and overheating, which can lead to tire failure and result in both equipment damage as well as in bodily injury.

Q: What are DOT tire ID numbers?

A: The Department of Transportation (DOT) identification number code is stamped on one side of the tire, near the bead. The code starts with the letters "DOT" and then has two numbers or letters to identify where the tire was manufactured. The last four numbers represent the week and year the tire was built. For example, the number 0410 means the fourth week of 2010.

Q: What are the different types of tires that Dexter sells for my trailer?

A: We sell several types of trailer tires, including bias tires and radial tires.

Bias Tire: Bias, or cross-ply construction tires, utilize body ply cords that extend diagonally from bead to bead, usually at angles in the range of 30 to 40 degrees, with successive plies laid at opposing angles forming a crisscross pattern to which the tread is applied. This design allows the complete tire body to flex easily, providing the main advantage of this construction – a smooth ride on rough surfaces. The cushioning characteristic of bias tires also causes its major disadvantages, which are increased rolling resistance and less control and traction at higher speeds.

Radial Tire: A radial tire is built with plies that cross the crown of the tire at an angle of 90 degrees. Radial tire construction utilizes body ply cords extending from the beads and across the tread. These cords are laid at approximately right angles to the centerline of the tread, and parallel to each other, with additional stabilizer belts directly beneath the tread. The belts may be nylon cord or steel. The advantages of radial construction include longer tread life, better steering control, and lower rolling resistance. Disadvantages of the radial tire include a harder ride at low speeds on rough roads and reduced traction at low speeds.