Mechanics

Tires

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The first pneumatic tire was made by Scot John Boyd Dunlop to aid his son's cycling. His son often complained of headaches caused by the bumps in the road. But officially Robert William Thomson was given credit of inventing the idea of the tire. Tire companies began establishing in the beginning of twentieth century. Since then there has been rapid growth of tire manufacturers and the top three tire companies are said to have sixty percent of the global market share. More than four hundred tire companies produce over one billion tires every year.

Basic Tire Size, Safety, Load and Pressure Information
Basic Tire Size, Safety, Load and Pressure Information

Tires are made out of flexible rubber which is incorporated with wire and fabric. The tires of an automobile support the braking, load, traction, and steering. Tires also absorb shock caused by bumps in the road and help provide a smooth ride to the passengers. Different styles of tires are available depending on application. Tire categories are solid, bias ply, and radial.

Car Tire Basic Manufacture Configuration
Car Tire Basic Manufacture Configuration

You can reduce the maintenance and repair of your vehicle by checking the tire pressure with a tire pressure gauge regularly. After an air pressure examination, reinstall the valve cap to prohibit moisture from entering the valve stem mechanism. Tires can have different life expectancies depending on driver habits and road conditions. Inspecting tire wear patterns can warn about possible suspension or steering problems.

Tire Wear Patterns
Tire Wear Patterns

Sometimes a tire will have unusual tread wear patterns like flat spots, cupping or extreme wear on one side of the tire. All these can be indications of weight overload, balance problem, under-inflation, failed front end suspension components or misalignment. Inspect tires for small punctures, cuts and embedded sharp objects like screws, nails, broken glass and metal. A puncture that is releasing air can be detected by spraying soapy water on the suspected area and look for bubbles. Tire repair patches can be glued to the interior of the tire. Tire plugs are also available in a tire repair kit and can be used for repairing a small puncture.

Anytime you check your car’s tires start with the vehicle on level ground, with the front wheels pointed straight. Your car’s tires are designed to run on a specific air pressure according to weight. If your tires are over inflated it will cause the center of the tire tread to wear out prematurely. Over inflation can also cause the tire to fail by blowout. If the tire is under inflated it will cause the tire to over work itself resulting in internal tire failure. Under inflation can also cause poor gas mileage by increasing the rolling resistance of the car.

A tire pressure gauge is designed to check the air pressure inside a tire. Correct tire pressure is essential for proper vehicle operation and can improve mileage and performance as well. A tire gauge is constructed with a small diaphragm that is attached to a measurement device. The style of gauge can vary from digital to internal slide. A tire gauge is accurate to +/- 3 PSI, however it is possible to buy more advanced models that are capable of determining the pressure to as closely as +/- 1 PSI.

If your tires have become “feathered” on either the front or the rear of the car it can mean a couple different things. If your tires are “feathered” on the outside off the tire it means the car alignment is toed-in or has positive camber. If the tires are “feathered” on the inside it means the cars alignment is toed out or it has negative camber. There are other things that can cause tires to wear incorrectly like suspension component failure, so have the suspension inspected before an alignment is performed. Tire “cupping” is a condition that is caused by the tire rapidly bouncing up and down as you drive. If your tires have developed “cupping” this means the tire is not balanced correctly or the shocks-struts have worn out and has lost the ability to hold the wheel steady resulting in the said “cupping” condition.

Tire Tread Wear Indicator
Tire Tread Wear Indicator

The tread wear can be tested with the help of tread depth indicator. Once the tread depth is at the specified minimum, the tire should be replaced. Most tires should be rotated at manufacturers recommended specifications. There are usually three rotation patterns, the directional tire rotation, non-directional rotation and alternate or cross rotation.

Tire Rotation Patterns
Tire Rotation Patterns

In a directional tire rotation the front tires are exchanged with the following back tires. In non-directional tire rotation the front and back tires are exchanges diagonally and so on. After the wheels are rotated, the air pressure in the tires should be checked and adjusted to specifications.

Run Flat Tires

A fairly new concept and construction of tires is the "run flat" tire that can be driven for a limited amount of time with little or no air pressure. There are two types of these run flat tires; one construction includes an inner bladder that is filled with air that is used when the main tire has lost its air pressure. The other style of run flat tire is constructed of a thicker rubber sidewalls that will stand and hold the vehicles weight for a limited amount of time will no or little air pressure. Both of these styles of tire are more expensive than a conventional tire. These "run flat" tires are good for people that cannot change a flat tire themselves.

As the popularity of these tires grows the cost will become more reasonable because the manufacturing process can be developed that is more efficient. If a vehicle is equipped with run flat tires from the factory, it usually means there is no spare tire for the vehicle, so you may want to do a little looking before you replace the tires with conventional ones, it may leave you stranded without a spare.

If further technical assistance is needed, our certified car repair technicians are ready to answer your car tire questions.

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AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-11-20)