Do I really need to replace all four tires at the same time?

By: Kristen Hall-Geisler  | 

Image Gallery: Car Safety Tires are displayed outside of a shop in San Jose, Calif. See pictures of car safety.
AP Photo/Marcio Jose Sanchez

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.

In vehicles with all-wheel-drive systems, including Subarus, Audis and Lamborghinis, the differential and the computer work together to send the right amount of torque to each wheel to minimize slippage and maximize control. If one of the tires is a different size than the others -- because three tires are worn and one is brand new -- the computer will take an incorrect reading and the differential will work too hard. Drive this way long enough and you'll burn out the drivetrain.

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There are exceptions, even for AWD vehicles. If the tires only have a couple thousand miles on them and one needs to be replaced, that's okay according to Dominick Infante, National Manager of Product Communications for Subaru. Also, if you need to use the small spare to limp to the nearest repair shop, that's probably not far enough to do any serious damage.

Remember to rotate your tires because it extends their life on any vehicle; but for AWD vehicles, rotating the tires also makes sure that the tread wears evenly and doesn't place a strain on the drivetrain.

For more information about tires and other related topics, follow the links on the next page.

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Originally Published: Aug 17, 2010

Replace Tires FAQs

Can I replace just one tire on my car?
For all-wheel-drive (AWD) cars, it is recommended that all four tires be replaced at the same time. This is because in these cars, the computer and differential work simultaneously to supply torque to each wheel, ensuring maximum control. If any tire is of a different size, owing to it being new while the others are worn by comparison, the computer will take a faulty reading thereby putting pressure on the differential. Driving the car like this will burn out the drivetrain. If it's a front- or rear-wheel drive car, and you got a flat, you may be able to replace just that tire depending on how much tread is left on the other tires.
Should I replace two or four tires?
In the context of all-wheel drive vehicles, you should replace all four at the same time. On two-wheel drives, if you don't plan on replacing all four, it's best to replace in pairs, the two front or the two rear, depending on which tire(s) need replacement.
Do all my tires have to be the same brand?
If you're replacing just only one tire, make sure it is the same model, size and tread pattern as the others on your car. A different brand or model will have greater differences in traction and number of revolutions per mile than the others and may cause that new tire to wear out faster.

Lots More Information

Related Articles

  • Infante, Dominick. National Manager of Product Communications, Subaru of America. Personal Interview. Conducted on Aug. 3, 2010.
  • TireRack.com "Matching Tires on Four-Wheel Drive and All-Wheel Drive Cars." (July 29, 2010) http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=18

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