Highway Tire and Auto - Consumer Tire Guide

Consumer Tire Guide

Things you need to know about
auto and light truck tire care
and safety

TIRE INDUSTRY SAFETY COUNCIL - CTG-8/90

TIRE PLACARD AND SAFETY WARNING

Tires are designed and built with great care to provide thousands of miles of excellent service. But for maximum benefit they must be maintained properly.

The most important factors in tire care are:

Proper Inflation Pressure
Proper Vehicle Loading
Regular Inspection
Good Driving Habits

TIRE INFLATION PRESSURE

With the right amount of air pressure, your tires wear longer, save fuel and help prevent accidents. The "right amount" of air is the pressure specified by the vehicle manufacturer for the front and rear tires on your particular model car or light truck. The correct air pressure is shown on the tire placard (or sticker) attached to the vehicle--door edge, door post or glove box door. If your vehicle doesn't have a placard, check the owner's manual or consult with the vehicle or tire manufacturer for the proper inflation.

The tire placard tells you the maximum vehicle load, the cold tire pressures and the tire size recommended by the vehicle manufacturer.

If you don't take proper care of your tires, the results can be serious. Most manufacturers now mold a safety warning on the sidewall of the tire.

It points out that serious injury may result from tire failure due to underinflation or overloading. Motorists are strongly advised to follow the vehicle owner's manual or the tire placard in the vehicle for proper inflation and loading.

Only specially trained persons should demount or mount tires. An explosion of a tire and wheel assembly can result from improper or careless mounting procedures.

WARNING

Serious injury may result from:

Tire failure due to underinflation/overloading. Follow owner's manual or tire placard in vehicle.
Explosion of tire/rim assembly. Only specially trained persons should mount tires.

Your Own Tire Pressure Gauge

Tire must be properly inflated. Determine tire inflation by using an accurate tire pressure gauge. You can't tell when tires are "low," or under-inflated just by looking. Air meters at service stations may be inaccurate due to exposure or abuse. You should have your own personal tire gauge to be sure.

Purchase an accurate tire gauge from your tire dealer, auto supply store or other retailer. Make sure it is calibrated up to 80 PSI. You can order one by mail from the Tire Industry Safety Council. (See back cover for details)

Special Tips:

Check tire inflation pressure (including the spare) at least once a month and before every long trip. Tires must be checked when they are cold; that is, before they have been run a mile. If you must drive over one mile for air, before you leave home, measure the cold inflation pressure of each tire and record the actual under-inflation amount for each tire.

Upon arriving at the service station, measure each tire's inflation again and then inflate the warm tire to a level that is equal to this warm pressure plus the cold under-inflation amount.

When outdoor temperature changes occur, your tire's inflation pressure is affected. For every 10 degree (Fahrenheit) drop in temperature, tire pressure will drop one pound per square inch. In hot weather, tires can lose up to two pounds of air per month. Under-inflation is the leading cause of tire failures so check inflation pressure regularly.

Never "bleed" or reduce air pressure when tires are hot. It is normal for pressures to build up as a result of driving.

Make sure all tire valves and extensions, where possible, are equipped with valve caps to keep out dirt and moisture. Install a new valve stem assembly whenever a tire is replaced.

Under-inflation or overloading creates excessive heat, and can lead to tire failure, which could result in vehicle damage and/or serious injury or death. Proper inflation extends tire life and saves fuel. Maintain the inflation pressure listed in the vehicle owner's manual or on the tire placard (See page 2.)

Proper Vehicle Loading

The tire placard shows the vehicle manufacturer's recommended cold inflation pressure. You must not overload the vehicle. Remember, baggage carried on top of any vehicle counts as additional load.

If you are towing a trailer, remember that some of the weight of the loaded trailer transfers to the towing vehicle. That reduces the payload which can safely be placed in the towing vehicle. The only sure way to prevent overload is to weigh, axle by axle, the fully loaded vehicle on reliable platform scales.

Load and inflation information for popular auto tire sizes may be obtained from your local tire dealer, or tables may be obtained free by sending a stamped, self-addressed business-size envelope to "Tables," Tire Industry Safety Council, Box 1801, Washington, D.C. 20013.

Inspect Your Tires Regularly

At least once a month inspect your tires closely for signs of uneven wear.

Uneven wear patterns may be caused by improper inflation pressures, misalignment, improper balance or suspension neglect. If not corrected, further tire damage will occur.

Most likely the cause will be corrected at your tire dealer or other service facility. If you catch a problem and correct it in time, your tires may be able to continue in service.

Certain uneven wear patterns may indicate that the tire has suffered internal structural damage and requires the immediate attention of your tire dealer.

When the tread is worn down to one-sixteenth of an inch, tires must be replaced. Built-in tread-wear indicators, or "wear bars," which look like narrow strips of smooth rubber across the tread, will appear on the tire, when that point of wear is reached.

When you see those wear bars, the tire is worn out and it's time to replace it.

As you inspect your tires, look for any stones, bits of glass, metal or other foreign objects wedged in the tread, which may work deeper into the tire and cause air loss.

If any tire continually needs more air, have it taken off the vehicle and checked to find out why it's leaking. Damage to the tire, wheel or valve may be the problem.

Good Driving Habits

The way you drive has a great deal to do with your tire mileage and safety. So cultivate good driving habits for your own benefit.

Observe posted speed limits.
Avoid fast starts, stops and turns.
Avoid potholes and objects on the road.
Don't run over curbs or scuff the sidewall of a tire against the curb when parking.

Avoid Tire Spinning

The centrifugal forces created by a rapidly spinning tire can cause an explosion by literally tearing the tire apart. These forces act on the complete tire structure, and can be of such magnitude as to break beads as well as to rupture the entire carcass. Some vehicles are capable of bringing a tire to its centrifugal force failing point in 3 to 5 seconds.

When stuck on ice, snow, mud or wet grass, the vehicle should be rocked gently (alternately using forward and reverse gears) with the least amount of wheel spinning. If that doesn't free the vehicle, get a tow.

Never exceed 35 mph speed indicated on the speedometer. Never allow anyone to stand near or directly ahead or behind the spinning tire.

No matter how carefully you drive, there is always a possibility that you may eventually have a puncture and wind up with a flat on the highway. Drive slowly to the closest safe area out of traffic. This may further damage the flat tire, but your safety is more important.

Follow vehicle manufacturer's instructions for jacking up the vehicle, taking off the wheel and putting on the spare. Then drive to a place where the flat tire can be inspected for possible repair or replacement.

After a tire has been severely impacted you must have it removed from the wheel and inspected both inside and out for impact damage.

An impact-damaged tire may appear serviceable on the outside, but can fail later after the road hazard injury.

Many late model vehicles are equipped with temporary spare tires and wheels which are different from your regular tires and wheels. Some may require higher inflation pressure, or the use of special canisters to inflate the tire.

You may operate a vehicle with such a tire, within the limits indicated on the tire's sidewall, until it is convenient to repair the disabled tire or replace it with one of the same size designation and construction as the other tires on the vehicle.

Consult your vehicle owner's manual and the tire sidewall for instructions on proper use of a temporary spare.

Always check the inflation in your spare tire every time you check all the others. A spare tire with no air in it is no help to you in an emergency. If you have an inflatable spare, be sure to check the aerosol air inflation pressure canister to be sure it has not been damaged. If so, have it checked by an expert.

Improper mounting and over-inflation may damage the tire or wheel and can result in an explosion that could cause serious injury and death. (See Safety Warning, Page 2).

WARNING

Tire explosion can cause death, personal injury or property damage.

Excessive speed in a free-spinning tire can cause it to "explode" from extreme centrifugal force.

Vehicle Conditions Affecting Tires

There is a close working relationship between your tires and several mechanical systems in your vehicle. Tires, wheels, brakes, shock absorbers, drive train, steering and suspension systems must all function together smoothly to give you a comfortable ride and good tire mileage.

BALANCE: An unbalanced tire and wheel assembly may create an annoying vibration when you drive on a smooth road and may result in irregular tread wear.

ALIGNMENT: Misalignment in the front or rear, improperly operating brakes or shock absorbers, bent wheels, sprung axle housings, worn bushings, etc., cause uneven and rapid tread wear and should be corrected by a qualified mechanic. Front wheel drive vehicles and those with independent rear suspension require additional attention with alignment of all four wheels.

All these systems should be checked periodically as specified by the vehicle owner's manual or whenever you have an indication of trouble.

A bad jolt can throw your front end out of alignment even if you had it checked an hour earlier. Such impact can also bend wheels, causing a loss of air pressure, and damage your tires with little or no visible external indication.

TIRE ROTATION: Sometimes irregular tire wear can be corrected by rotating your tires. Consult your car owner's manual or the tire manufacturer for the appropriate pattern for your vehicle.

If your tires show uneven wear, ask the service person to check for and correct any misalignment, imbalance or other mechanical problem involved before rotation.

After rotation, adjust individual tire air pressure to the figures recommended by the vehicle manufacturer for their new location--front or rear--as shown on the tire placard in the vehicle. (See page 2.) Sometimes front and rear tires on a vehicle use different pressures.

The purpose of regularly rotating tires is to achieve more uniform wear for all tires on a vehicle. Before rotating tires, always refer to individual owner's manuals for rotation recommendations for specific vehicles. If no rotation period is specified, tires should be rotated every 6000 miles or at any sign of uneven wear. The first rotation is most important.

Do not include a "Temporary Use Only" spare tire in any rotation patterns. If you have a matching full size tire as a spare and wish to include it in the rotation process, insert the spare in the right rear position and place the tire that would have gone on the right rear in the trunk as the new spare.

The Sidewall Story

Your tire contains a lot of useful information molded into the sidewall. It shows the name of the tire, its size, whether it is tubeless or tube type, the maximum load and maximum inflation, the important safety warning (see page 2) and much other information.

On the sidewall of a popular "P-metric" speed-rated auto tire, "P" stands for passenger; "205" represents the width of the tire in millimeters; "60" is the ratio of height to width; "H" is the speed rating; "R" means radial, and "15" is the diameter of the wheel in inches. Some speed-rated tires carry a Service Description, instead of showing the speed symbol in the size designation. The Service Description, 90H in this example, consists of the load index and speed symbol.

A "B" in place of the "R" means the tire is a belted bias construction. A "D" in place of the "R" means diagonal "bias" construction.

The maximum load is shown in lbs. (pounds) and in kg. (kilograms), and maximum pressure in PSI (pounds-per-square inch) and in kPa (kilopascals). Kilograms and kilopascals are metric units of measurement.

The letters "DOT" certify compliance with all applicable safety standards established by the U.S. Department of Transportation (DOT). Adjacent to this is a tire identification or serial number. This serial number is a code with up to eleven digits that are a combination of numbers and letters.

The sidewall also shows the type of cord and number of plies in the sidewall and under the tread.

The DOT requires tire manufacturers to grade passenger car tires based on three performance factors: Treadwear, Traction, and Temperature Resistance.

TREADWEAR: The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test track. A tire graded 200 would wear twice as long on the government test course under specified test conditions as one graded 100.

However, it is erroneous to link treadwear grades with your projected tire mileage. The relative performance of tires depends upon the actual conditions of their use and may vary due to driving habits, service practices, differences in road characteristics and climate.

TRACTION: The traction grades, from highest to lowest, are A,B and C. They represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete.

TEMPERATURE: The temperature grades are A (the highest) B and C, representing the tire's resistance to the generation of heat when tested under controlled conditions on a specified indoor laboratory test wheel.

The typical information on the sidewall of a light truck tire:

LT -- stands for Light Truck. "LT235/85R16" is the size designation for a metric light truck tire. "LOAD RANGE D" identifies the load and inflation limits;

RADIAL identifies that the tire has a radial construction. "MAX LOAD SINGLE 2623 lbs. AT 65 psi COLD" indicates the maximum load rating of the tire and corresponding minimum cold inflation pressure for that load when used as a single. For normal operation, follow pressure recommendations in owner's manual or on vehicle placard; "MAX LOAD DUAL 2381 lbs. AT 65 psi COLD" indicates the maximum load rating of the tire and corresponding minimum cold inflation pressure when used in a dual configuration. The other markings on the sidewall have the same meaning as described for the passenger car tire.

Replacement Tire Selection

IMPORTANT: Always check the vehicle manufacturer's recommendation before replacing a tire with a different size and/or construction.

When buying new tires, be sure your name, address and tire identification number (DOT code) are recorded and returned to the tire manufacturer or his record-keeping designee. Tire registration enables the manufacturer to notify you in the event of a recall.

When tires need to be replaced, don't guess what tire is right for your vehicle.
For the answer, first look at the tire placard. (See page 2.) As you will see, that placard tells you the size of the tires which were on the vehicle as original equipment.

Tires should always be replaced with the same size designation, or approved options, as recommended by the automobile or tire manufacturer. Never choose a smaller size, with less load carrying capacity than the size on the tire placard. Always mount tires with the same size and construction designations on the same axle.
It is preferred that all four tires be of the same size, speed rating, and construction (radial or non-radial).

When two radial tires are used with two non-radials, put the radials on the rear axle.
Some tires are now marked with letters to indicate their speed rating, based on laboratory tests which relate to performance on the road. Tires may be marked with one of six speed symbols, "S, T, U, H, V, or Z" to identify the particular tire's speed rating.

When replacement of tires is required, consult the vehicle manual for proper size and speed rating (if required). If the vehicle manual specifies speed rated tires, the replacement tires must have the same or higher speed rating to maintain vehicle speed capability.

If tires with different speed ratings are mounted on the same vehicle, the tire or tires with the lowest rating will limit permissible tire related vehicle speed.

Tire speed ratings do not imply that vehicles can be safely driven at the maximum speed for which the tire is rated, particularly under adverse road and weather conditions or if the vehicle has unusual characteristics. Never operate a vehicle in an unsafe or unlawful manner.

It is preferred that all tires be of the same size, construction (radial, non-radial) and speed rating. Tires influence vehicle handling and stability.

Match tire size designations in pairs on an axle (or four tires in dual application), except for use of a temporary spare tire.

If radial and non-radial tires are used on a vehicle, put radials on the rear. If radial and non-radial tires are used on a vehicle equipped with dual rear tires, the radials may be used on either axle. Never mix radial and non-radial on the same axle except for use of a temporary spare tire.

Snow tires should be applied in pairs (or as duals) to the drive axle (whether front or rear) or to all positions. Never put non-radial snow tires on the rear if radials are on the front, except when the vehicle has duals on the rear. If studded tires are used on the front axle, they must also be used on the rear axle.

Match all tire sizes and constructions on four-wheel drive vehicles.

Cold Weather Driving

Many parts of the U.S. have cold weather driving conditions at least part of the year. Here are some things you should know about cold weather driving:

Every time the outside temperature drops 10 degrees Fahrenheit, the air pressure inside your tires goes down about one (1) pound per square inch.

You should check your tire pressures frequently during cold weather and add the necessary air to keep them at recommended levels of inflation at all times.

Never reduce tire pressures in an attempt to increase traction on snow or ice. It doesn't work and your tires will be so seriously under-inflated that driving will damage them.

If one of the drive wheels becomes stuck, the centrifugal forces created by a rapidly spinning tire can cause an explosion by literally tearing the tire apart. Never exceed the 35 mph indicated speedometer speed or stand near the spinning tire.

In snowy areas, many cities and counties have "snow emergency" regulations which are invoked during heavy snowfalls. Check with authorities for the rules in your area. Under some rules, motorists are subject to fines if they block traffic and do not have snow tires on their vehicles.

You can avoid this by equipping your vehicle with snow tires marked with "MS," "MS," "M&S," "M + S," etc. on the sidewall.

If you change to snow tires, be sure they are the same size and construction type as the other tires on the vehicle.

Snow tires should be used in pairs (or as duals) on the drive axle (whether front or rear) or on all four wheel positions. Never put non-radial snow tires on the rear if radials are on the front, except when the vehicle has duals on the rear.

In areas where heavy snowfalls are frequent, many drivers carry chains for use in emergencies, or have their tire dealer apply studded snow tires.

When studded snow tires are mounted on the front axle, studded tires also must be placed on the rear axle.

Most states have time limits on use of studs or ban them altogether. Before applying studded tires, check the regulations in your area. If you use chains, make sure they are the proper size and type for your tires. Otherwise they may damage the tire sidewall and cause tire failure.

Service Assistance

When you have a question about tires, or a problem, consult your tire dealer. He is the best source of general information and professional service on tires.

He has service manuals, wall charts and other industry publications on tire load and inflation, tire repair and tire replacement. He can provide you with the replacement tires your vehicle needs, balance your tires and repair damaged tires which are repairable. Let him inspect your tires periodically, and diagnose any problem you may have.

When you discover a tire is losing air, it must be removed from the wheel by an expert for complete internal inspection to be sure it is not damaged. Tires run even short distances while severely under-inflated may be damaged beyond repair.

Punctures up to 1/4 inch, when confined to the tread, may be repaired by trained personnel. These tires must be removed from the wheel, inspected and repaired using industry approved methods which call for an inside repair unit and a plug.

A PLUG BY ITSELF IS AN UNACCEPTABLE REPAIR. Never use a tube in a tubeless tire as a substitute for a proper repair.

Individual tire manufacturers may differ on whether the speed category applies to speed rated tires that have been repaired. Consult the tire manufacturer for recommendations.

Injuries larger than 1/4 inch must be referred to a full service repair facility. No repairs to the sidewall of a tire should be made without consulting the tire manufacturer. After a tire has been repaired, check for leaks or other damage not detected at the time of repair. Improper repairs can cause sudden tire failure.

Air loss due to punctures can ruin tires that could have been saved had they been removed in time for proper repair. Gradual air loss raises a tire's operating temperature. This can cause some of the components to separate, or damage the tire body in ways that create rapid or sudden air loss.

Such internal damage may not always be readily apparent and rapid loss of air may still occur despite later installation of a proper repair.

Save Gas With Proper Tire Inflation!

Check Your Tires At Least Once A Month--And Before Long Trips

Special Combination Kit Available

Contains:

Air pressure gauge
Tread depth gauge
Four tire valve caps
A copy of this 12-page Consumer Tire Guide.

ALL FOR ONLY $4.00 Comes in plastic pouch

If you only need a tire gauge, order this one for $2.50. Calibrated to 80 pounds per square inch. Check all automobile tires, including high inflation temporary spares.

Send Check or Money Order to:

Tire Industry Safety Council

Box 1801 Washington, D.C. 20013

(District of Columbia residents add local sales tax)

Prices subject to change after July 1, 1992.

Published in cooperation with:

National Highway Traffic Safety Administration U.S. Department of Transportation
American Automobile Association
American Driver & Traffic Safety Education, Association
American Petroleum Institute
Highway Users Federation
National Safety Council
National Tire Dealers and Retreaders Association

DISTRIBUTED BY

"TISC is a not-for-profit public education and tire safety advocacy group supported by tire manufacturers. The Tire Safety and Mileage Kit and the air gauge device are sold at cost as an adjunct to TISC's public education programs."

Follow Us

Consumer Tire Guide

WARNING

Your Own Tire Pressure Gauge

Inspect Your Tires Regularly

Good Driving Habits

Avoid Tire Spinning

WARNING

Vehicle Conditions Affecting Tires

The Sidewall Story

Replacement Tire Selection

Cold Weather Driving

Service Assistance

Special Combination Kit Available

copyright © 2024 Highway Tire and Auto. All Rights Reserved.