Tires and Wheels

Choosing a good quality tire that is correct for your vehicle involves knowledge of how tires are constructed and graded, and also requires expert handling in selecting and installing the new tires; at Ewell Auto Service in Fort Worth, our technicians have the experience and equipment not only to help you choose new tires, but also to maintain them properly with routine alignment, balancing, and rotation.

All tires are not equal.

A tire has a loop of steel cable coated with rubber to give the tire strength. The body of the tire is made up of several layers, or plies (usually two), of fabric (usually polyester cord) coated with rubber. Belts made from steel reinforce the tire, keep it more level to the road, and prevent punctures. Sidewalls provide lateral stability. The tread is made from a mixture of kinds of rubbers so that when the tire goes through its curing process (vulcanizing) that bonds everything together, it emerges with a variety of patterns that give the tire traction on the road. Different tire manufacturers have different variations in these basic ingredients, making some tires better than others and some tires more or less suitable for your particular vehicle.

All the markings on a tire mean something important.

The first letter designates the type of vehicle the tire is meant for: P for passenger, LT for light truck, and T for temporary or spare tires. The numbers involve a formula that indicate two things; the height of the tire as a percentage of its width, and the width of the tire indicated in millimeters when the tire is on the rim; the formula gives what is called aspect ratio. But what is important to know is that the smaller the aspect ration indicated by the numbers, the wider the tire in relation to its height, so high-performance tires usually have a lower aspect ratio number shown on the tire. Next come letters indicating the way the tire was constructed: R for radial, D for diagonal, or B for bias belted. The rim diameter is given in inches.

Government testing gives each type of tire a rating which shows up on the tire.

Tires have a grade on them as part of the uniform tire quality grading system. The grade marking includes tested tread wear on a government test track; the higher the number the longer the tread can be expected to last. Tire traction is rated based on the tested ability of the tire to stop on wet surface (AA (best), or A, B or C); but note that this rating indicator does not measure cornering, only stopping on wet surfaces. The tire temperature ratings measure how well the tire deals with heat buildup and are also indicated by A, B or C marks. There is also a load rating and a speed rating for the maximum load capacity and the maximum speed suitable for the particular type of tire, but note that the number given on the tire is a rate on a scale, not the actual number of pounds of weight the tire can carry nor the speed indicated as safe for the tire. You have to look up the numbers on a chart to understand those details.

Over inflation or under inflation of a tire causes problems.

Under inflation cause tires to wear more on the outside and causes increased heat buildup in the tires. Over inflation causes tires to wear more in the center of the tread. To prevent either, it is important to have the tire pressure checked with a gauge, preferably at least once a month and adjust for proper inflation.

Proper alignment protects the tire, your safety, and the efficiency of the vehicle.

Wheel alignment makes sure the angles of the wheels are perpendicular to the ground and parallel to each other. Proper wheel alignment prevents tire wear and steering problems. Improper alignment can involve what is called tire “toe in” or “toe out,” it can involve angles that cause the car to pull to one side or the other, to vibrate or wobble or “kick back” when steering. Proper wheel alignment requires test driving the vehicle and also checking the steering linkage. If you have your vehicle’s wheels aligned but leave the vehicle with tires with certain wear patterns, you may have created further problems. Our wheel alignment technicians will figure out the problems, which could be a need for new tires, or could include the brakes and steering as well as the wheels and tires.

Tire balancing is different from wheel alignment.

Wheel alignment is often confused with tire balancing. The process of tire balancing has to do with the distribution of weight on the four tires. An out of balance tire can cause vibrations at highway speeds. Having tires out of balance shortens the life of tires, bearings, shocks and other suspension components.

Tire rotation is also important to the life of the tires.

Tire tread rubs off on the road surface as your car travels along the road. Front and rear tires wear in different ways and at different speeds, with front tires usually wearing faster and more on the outside of the tire. By occasionally rotating the tires front to back, all of the tires wear evenly, thus extending the life of the tires. Most technicians recommend tire rotation every 6,000 to 7,500 miles.

Check your vehicle's owner's manual for your manufacturer's recommendations, and then come on in to Ewell Tire Service in Fort Worth; we’ll help you choose the proper tires, install them correctly, and then, as needed, balance and align and rotate them for the longest life of the tires and for passenger safety.

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