Replace the tires at least every 6 years. If you're not sure, the minimum replacement time that is recommended by the NHTSA is six years regardless of use, with 10 years being the maximum service life for tires. Check your owner's manual for specific recommendations related to your car.s the tires wear, these bars will become flush (level or even) with the tire's tread. At this point, it's time to replace the tires. 3. Check the tread by using the penny test.  Take a penny, and place it upside down with Lincoln facing you in the center of the tread (at the thickest part of the tire).
http://www.wikihow.com/Know-when-Car-Tires-Need-Replacing
This allows for inflation, wear and manufacturing tolerances. So you do not need to replace all four tires when you have a flat but you do need to replace the tire with a similar size tire if it cannot be repaired. If all the tires are worn it would make sense to replace the entire set so that they are all matched. have had people tell me that if any one tire is more than 3/32 out that all 4 tires need to be replaced. You mentioned 1/2 inch, that seems like a lot of tolerance, so the tires could be through half of their life and we would only have to replace one tire.
http://www.justanswer.com/subaru/36w6j-truth-subaru-awd-cars-replacing-tires.html
So you do not need to replace all four tires when you have a flat but you do need to replace the tire with a similar size tire if it cannot be repaired.If all the tires are worn it would make sense to replace the entire set so that they are all matched. have had people tell me that if any one tire is more than 3/32 out that all 4 tires need to be replaced. You mentioned 1/2 inch, that seems like a lot of tolerance, so the tires could be through half of their life and we would only have to replace one tire.
http://www.justanswer.com/subaru/36w6j-truth-subaru-awd-cars-replacing-tires.html
1 On 4-wheel-drive or all-wheel-drive cars you should replace all four tires if it is recommended in your service manual. 2  Differences in tire diameter, even due to different states of tread wear, can permanently damage differentials.3  Treadwear grades are an indication of a tire's relative wear rate.s the tires wear, these bars will become flush (level or even) with the tire's tread. At this point, it's time to replace the tires. 3. Check the tread by using the penny test.  Take a penny, and place it upside down with Lincoln facing you in the center of the tread (at the thickest part of the tire).
http://www.wikihow.com/Know-when-Car-Tires-Need-Replacing
As the tires wear, these bars will become flush (level or even) with the tire's tread. At this point, it's time to replace the tires. 3. Check the tread by using the penny test.  Take a penny, and place it upside down with Lincoln facing you in the center of the tread (at the thickest part of the tire).1  If you can see the very top of Lincoln's head or the copper above it, replace the tires immediately.s the tires wear, these bars will become flush (level or even) with the tire's tread. At this point, it's time to replace the tires. 3. Check the tread by using the penny test.  Take a penny, and place it upside down with Lincoln facing you in the center of the tread (at the thickest part of the tire).
http://www.wikihow.com/Know-when-Car-Tires-Need-Replacing
Both those sites have owner reviews and you can get tire suggestions at the Sequoia Tires and Wheels discussion on CarSpace. tony78 04/03/09 12:20 am PST. Edit Answer (for another -7 minute). some cars are awd all the time,,if your car is awd all the time,,then ,,yes,,you have to replace all of the tires.ven though someone gave Tony78 a thumbsdown, I think he's mostly right, although I would not replace 1 tire. This should also be addressed in your owner's manual. The answer depends on whether this is AWD or 4x4. If its a part-time 4x4 system, then I don't think its necessary to replace all 4 tires.
http://www.answers.edmunds.com/question-Do-I-need-to-replace-all-4-tires-if-only-one-is-bad-I-have-a-4x4-Toyota-Sequoia-with-40-000-miles-51740.aspx
The answer to this question really depends on your car. Most of the cars on the road today are front-wheel-drive, and a few are rear-wheel drive. These don't necessarily need to have all four tires replaced at once.Usually two at a time is sufficient.But all-wheel-drive systems are becoming more popular, and they do require all four tires to be replaced at one time. So for AWD vehicles, the short answer is yes, but let's find out why.hese don't necessarily need to have all four tires replaced at once. Usually two at a time is sufficient. But all-wheel-drive systems are becoming more popular, and they do require all four tires to be replaced at one time.
http://auto.howstuffworks.com/replacing-tires.htm
By using snow tires in the winter, you can opt for a summer tire better suited to your tastes -- be that a quieter, more comfortable ride, better handling, improved rain performance or longer tread-life. DO buy four tires at once. New tires generally grip the road better than tires that have some miles on them.It's best to replace all four tires at once, but if you must replace them in pairs, put the new tires on the back (regardless of whether the car is front-or rear-wheel-drive).y using snow tires in the winter, you can opt for a summer tire better suited to your tastes -- be that a quieter, more comfortable ride, better handling, improved rain performance or longer tread-life. DO buy four tires at once. New tires generally grip the road better than tires that have some miles on them.
http://cars.about.com/od/adviceforowners/a/tiredosanddonts.htm
While it is simple to place a Lincoln penny in the tread groove of a worn tire and use Abe's likeness as a guide, we don't think Honest Abe knows what's best for today's drivers.The Lincoln penny tread depth test has been touted for years to be a suitable method of determining when it's time to get new tires.hile it is simple to place a Lincoln penny in the tread groove of a worn tire and use Abe's likeness as a guide, we don't think Honest Abe knows what's best for today's drivers.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=157
Tires don't require tread designs or even much tread depth to deliver traction on dry roads. A practical example of this is the racing slicks used on stock cars and open-wheel racers that provide traction at over 200 mph. However, tires do require tread designs to generate traction on wet, slushy and snow-covered roads.hile it is simple to place a Lincoln penny in the tread groove of a worn tire and use Abe's likeness as a guide, we don't think Honest Abe knows what's best for today's drivers.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=157
when do i have to change tires
Replace the tires at least every 6 years.