The tire industry has long recognized the consumers' role in the regular care and maintenance of
their tires. The point at which a tire is replaced is a decision for which the owner of the tire is
responsible. The tire owner should consider factors to include service conditions, maintenance
history, storage conditions, visual inspections, and dynamic performance. The consumer should
consult a tire service professional with any questions about tire service life. The following
information and recommendations are made to aid in assessing the point of maximum service life.
Tires are designed and built to provide many thousands of miles of excellent service. For maximum
benefit, tires must be maintained properly to avoid tire damage and abuse that may result in tire
disablement. The service life of a tire is a cumulative function of the storage, stowing, rotation and
service conditions, which a tire is subjected to throughout its life (load, speed, inflation pressure, road hazard injury, etc.). Since service conditions vary widely, accurately predicting the service life
of any specific tire in chronological time is not possible.
The Consumer Plays an Important Role in Tire Maintenance
Tires should be removed from service for numerous reasons, including tread worn down to
minimum depth, damage or abuse (punctures, cuts, impacts, cracks, bulges, underinflation,
overloading, etc). For these reasons tires, including spares, must be inspected routinely, i.e., at
least once a month. Regular inspection becomes particularly important the longer a tire is kept in
service. If tire damage is suspected or found, Continental recommends that the consumer have the
tire inspected by a tire service professional. Consumers should use this consultation to determine if
the tires can continue in service. It is recommended that spare tires be inspected at the same time.
This routine inspection should occur whether or not the vehicle is equipped with a tire pressure
monitoring system (TPMS).
Consumers are strongly encouraged to be aware of their tires' visual condition. Also, they should be
alert for any change in dynamic performance such as increased air loss, noise or vibration. Such
changes could be an indicator that one or more of the tires should be immediately removed from
service to prevent a tire disablement. Also, the consumer should be the first to recognize a severe
in-service impact to a tire and to ensure that the tire is inspected immediately thereafter.
Tire storage, stowage and rotation are also important to the service life of the tire. More information
regarding proper storage, stowage and rotation is located in other Continental publications, which
are available upon request and through its websites.
Tire Service Life Recommendation
Continental is unaware of any technical data that supports a specific tire age for removal from
service. However, as with other members of the tire and automotive industries, Continental
recommends that all tires (including spare tires) that were manufactured more than ten (10) years
previous be removed from service and be replaced with new tires, even when tires appear to be
usable from their external appearance and if the tread depth may have not reached the minimum
wear out depth. Vehicle manufacturers may recommend a different chronological age at which a tire
should be replaced based on their understanding of the specific vehicle application; Continental
recommends that any such instruction be followed. Consumers should note that most tires would
have to be removed for tread wear-out or other causes before any proscribed removal period. A
stated removal period in no way reduces the consumer's responsibility to replace tires as needed.
The Chronological Age of the Tires
The chronological age of any tire can be found on the tire sidewall by examining the characters
following the symbol "DOT".
For tires manufactured after the year 1999, the last four numbers identify the date of manufacture of
the tire to the nearest week. The first two of these four numbers identify the week of manufacture
(which range from "01" to "52"). The last two numbers identify the year of manufacture (e.g., a tire
with the information "DOT XXXXXX2703 was manufactured in the 27th week of 2003).
For tires manufactured prior to the year 2000, three numbers instead of four indicate the date of
manufacture. Also, during the early 1990's, Continental added a triangle to the end of the
character string to distinguish a tire built in the 1990's from previous decades (e.g., a tire with the
information "DOT XXXXXX274 was manufactured in the 27th week of 1994).
Please note: This document supersedes PSIB 05 - 02
Your tires are the only part of your vehicle that actually touches the road when you drive. It only takes a couple of minutes of maintenance each month to keep your tires working at their best.
Incorrect air pressure is the leading cause of tire damage. To avoid tire damage you need to check your tire's air pressure once a month.
The correct tire pressure can be found in the following places:
- in the car's owner manual
- gas tank lid
- driver's side door's edge
- door post
The air pressure listed on the side of your tire is NOT the correct air pressure for your vehicle. That number is the maximum air pressure for the tire.
Don't get stranded and avoid costly towing expenses. Check your air pressure on your spare regularly. Note: If you have different rims than came on your vehicle originally, make sure that the bolts on your spare tire are the correct fitting.
Failure to keep your tires properly inflated can increase wear and will have a negative effect on your vehicles handling.
When checking and adjusting tire pressure, the following should be kept in mind:
- Check the air pressure when the tire is cold - tires become hot even after driving just a mile. If you must drive to add air, check your air pressure before you leave. Air pressure changes 1-2 pounds for every 10 degrees of temperature change. Air pressure goes up in warm weather and down in cold weather.
- Tire pressure must be the same on the tires of each axle, but may be different on the front and rear axle.
- Valve caps must be tightly closed to protect the valve from dust and dirt and prevent it from leaking.
- Replace missing valve caps without delay.
- Take this opportunity to inspect your tires to make sure there are no punctures and they are free of deformities.
To prevent hydroplaning and skidding, your tires must have proper tread depth. The minimum tread depth is 1/16th of an inch.
Ask anyone: the easiest way to check your tread depth is the penny test. Take a penny and place it in the tread of your tire. If part of Lincoln's head is covered by the tread, your tires have enough tread. If you can see Lincoln's entire head, you should buy a new tire.
You should also check your tire tread for uneven wear. Irregular wear shortens the life of your tires. If you think you have uneven wear, you should take you vehicle to your tire dealer.
The best way to prevent uneven wear is to have your tires rotated every 5,000 - 7,000 miles or as specified in your vehicle's owner manual.
- Curbs can prove to be big trouble to your tires. Approach curbs with care, if you drive over them too fast or at the wrong angle the impact may cause the tire to crack.
- Avoid potholes or debris in the road when possible.
- Avoid fast stops & starts.
- Be sure to check your owner's manual for your vehicles maximum load. Overloading your vehicle can shorten your tire life.
You should replace your tires with the same type of tires that came on your vehicle original equipment. This includes tire size, type and speed rating.
Driving in the rain can be dangerous; in fact thousands of car accidents each year are caused by wet driving conditions.
It is a good idea to always check your tires before you hit the road. To ensure your tires are working at their best, make sure you do the following routine maintenance:
- Keep your tires properly inflated. The correct air pressure for your tires is specified by the vehicle manufacturer and can be found on the vehicle door edge, door post, glove box door or fuel door. It is also listed in the owner's manual. The number listed on the side of the tire is not the recommended air pressure for your tire -- it is the maximum air pressure for the tire. You should check your tire's air pressure at least once a month.
- Check the tires tread depth. Tires should have 1/16 inch tread depth in order to perform the in the way for which they were designed. Proper tread depth will help prevent skids and hydroplaning.
Have your tires rotated at least every 6,000 - 7,000 miles. This will aid in detecting alignment problems and help prevent irregular wear.
As rain falls, it mixes with grime and oil on the road creating slick conditions perfect for skids. The best way to avoid skidding is to slow down. Driving at a slower pace allows more of the tire's tread to make contact with the road, which leads to better traction.
Skids can even happen to the most cautious drivers. If your car does skid, remember not to slam on the brakes, and do not pump the brakes if you have an anti-lock braking system (ABS). Instead apply pressure to the brakes in a firm manner and steer the car in the direction of the skid.
It takes about three times longer to break on wet roads than on dry roads. Since more distance is required to brake, it is important not to tailgate. Keep more than two car lengths between you and the vehicle in front of you.
When it rains, water creates a barrier between the road and your tires. The liquid film that forms can cause you to lose traction and glide or hydroplane across the water's surface. If this happens, do not brake. It is better to take your foot off the gas, hold the steering wheel in place, and lightly apply the brakes. If you have a manual transmission, push in the clutch and let the car slow down on its own.
Thanks to their special compound, winter tires offer the elasticity required to ensure maximum grip throughout the cold season, regardless of the road conditions. Summer tires can become hard when the temperature falls below 45 degrees, thereby losing the flexibility needed to build up sufficient grip for braking, starting off and cornering. Because of their greater suppleness in the cold, winter tires are able to interlock with asphalt, snow and ice, even at lower temperatures.
- Listen to the weather report the evening before. If snow is predicted, you should plan to get going earlier, because of traffic jams and delay. In really treacherous weather, the safest thing to do is stay home.
- Before taking off, make sure all car windows are completely clear of snow and ice; if you try to get by with just a peephole, you may end up sharing the blame for an accident.
- Check your rearview mirror and then test your brakes as soon as it is safe to do so. This will give you a feeling for road conditions.
- Avoid shortcuts via residential side streets. These roads are cleared last, if at all.
- Allow an extra wide safety margin when stopping at traffic lights and intersections and pay close attention to the vehicles in front of you.
- Avoid braking just before the intersection, where it is usually especially slippery.
- Be especially careful when crossing bridges! They can be treacherously slippery in winter because they are "cooled" from above and below. Fog can form ice on very cold days and make roads slick.
- Each month, three out of four drivers wash their cars while only one out of seven correctly checks their tire pressure.
- Motorists rank checking tire pressure as the second most important regular vehicle safety action, but more than three times as many drivers believe regular oil changes are most important to the safe operation of their vehicles
- Only 15 percent of drivers properly check their tire inflation pressure.
| To properly check tire inflation pressure: |
| Check tire inflation pressure at least once a month |
| Use the correct inflation pressure recommended by the vehicle manufacturer, not the pressure listed on the tire sidewall |
| Check tires when they are cold or haven't been driven for at least three hours |
- More than half of drivers -- 55 percent -- incorrectly believe that the correct inflation pressure is printed on the tire sidewall.
- Two out of three drivers don't know how to tell if their tires are bald.
- 71 percent of drivers do not check their tire pressure in their spare tire.
Proper tire care and safety is simple and easy. The Rubber Manufacturers Association (RMA) recommends getting in the habit of taking five minutes every month to check your tires, including the spare.
- Pressure: Underinflation can lead to tire failure. It results in unnecessary tire stress, irregular wear, loss of control and accidents. A tire can lose up to half of its air pressure and not appear to be flat!
- Alignment: A bad jolt from hitting a curb or pothole can throw your front end out of alignment and damage your tires. Have a tire dealer check the alignment periodically to ensure that your car is properly aligned.
- Rotation: Regularly rotating your vehicle's tires will help you achieve more uniform wear. Unless your vehicle owner's manual has a specific recommendation, the guideline for tire rotation is approximately every 6,000-8,000 miles.
- Tread: Advanced and unusual wear can reduce the ability of tread to grip the road in adverse conditions. Visually check your tires for uneven wear, looking for high and low areas or unusually smooth areas. Also check for signs of damage.
If you think you may have a tire problem or are unsure of the condition of your tires, consult a tire dealer as soon as possible.
Download the RMA's informative brochure "Be Tire Smart ... Play Your PART." (Adobe Acrobat Reader required.)
For more information, visit the Rubber Manufacturers Association at http://www.rma.org or the Rubber Association of Canada at http://www.rubberassociation.ca.
The RMA sponsored survey was conducted by FrederickPolls to 2,200 drivers nationwide from January 29-February 11, 2004 and has a margin of error of +/- 2 percent.
