Next to housing, personal transportation is the second highest expense in a lot of people’s lives. Given that it is such a large expense, it makes a lot of sense to keep your vehicle in its best condition for the longest period of time which minimizes your total cost of ownership or TCO. The extreme example is a 1966 Volvo 1800S driven by its original owner, Irv Gordon of East Patchogue, New York. On September 24, 2013, this car reached 3 million miles!
Image by Doug Coldwell / CC-BY-SA-3.0
Whether you’re expecting to get 3 million miles or 100,000 miles from your car, one of the things you can do to reduce costs is regularly rotate your tires. Each tire on your vehicle experiences different types of wearing forces. The driving wheels exert the torque of the engine through the tires to accelerate the vehicle. During hard braking, the front tires experience about 80% of the braking force due to the shift in weight distribution. The front tires also have to deal with the majority of the cornering forces when steering the car. All of this results in each tire wearing at a different rate and in a different manner. Moving the tires around to each of the four positions helps even out the wear.
Tire tread design also has a lot to do with how the tires wear. Some tires with aggressive tread patterns will wear more unevenly than tires with a less aggressive design. Obviously, you should choose your tires based on your expected driving conditions, just be aware that the design will affect how often you need to rotate and the rotation pattern that is best for the tires. Uneven tire wear not only shortens the life of your tires, it can also generate a lot of noise while driving. This extra noise can be unpleasant and fatiguing.
How Often?
The common wisdom in the automotive world is to rotate your tires every 6,000 to 8,000 miles (9,600 to 12,900 km). However, there are a lot of factors that can affect that interval. Your driving style, road conditions, wheel balance and alignment, vehicle loading, and tire design all affect how the tires wear on your particular vehicle. The best way to determine the proper rotation cycle time is to check your tires once a month. Rub your fingers along the outer and inner tread of the tire in the direction of rotation, and then reverse direction and check for sharp, raised edges of tread blocks (a condition called heel-toe wear). If you feel raised edges when moving opposite the normal rotation direction, it’s probably time for rotation.
Once you have rotated your tires a few times based on this monthly check, you may be able to determine a normal schedule based on miles alone. If you do switch to a mileage based check, make sure you start the monthly check again if you get a new set of tires or if the normal driving conditions change. Driving conditions include a change in the type of driving (highway vs. back roads) or a change in drivers.
Manufacturer's Data Decal
One of the largest factors in tire wear is tire pressure. Keeping your tires at their optimum pressure is critical for safety as well as reducing wear. You can follow your vehicle manufacturer’s recommendation for tire pressure, but I find they can be a little low. You should also consider your vehicle’s weight distribution and loading when setting tire pressures. Front wheel drive cars tend to be front heavy and should have higher tire pressures for the front tires.
Rotation Patterns
A lot has been written and debated about the best rotation patterns to use when rotating tires. The common practice is to move the driving wheels to the non driving wheel positions, keeping them on the same side of the car. Then move the non driving wheels to the driving wheel positions but switch sides. Switching sides will cause the wheel to rotate in the opposite direction which is a good way to offset wear factors caused by rotation direction. However, if your vehicle has unidirectional tires, you cannot switch sides. Unidirectional tires have special tread patterns that are designed to work best in one direction. They usually have a large arrow on the sidewall indication the correct rotation direction.
As with rotation intervals, I have found that rotation patterns are not always a hard and fast rule. Let your tires tell you what rotation pattern is best at the time of rotation. Tires that have noticeable heel-toe tread block wear should switch sides during rotation regardless of whether they are the driving wheels or not. However, this can also indicate an incorrect wheel alignment. If it’s been a while since your vehicle has had an alignment, maybe it’s time to have it done. Make sure to get a four wheel alignment unless your vehicle has a non-independent rear suspension which usually isn’t adjustable.
If your vehicle already has one or more tires that have significant abnormal wear patterns, you may want to keep those tires on one end of the car instead of rotating them front to back or back to front. Sometimes placing those tires on the front can make the vehicle very noisy and cause vibrations in the steering wheel. Keeping them on the rear is usually best, but you can switch sides in the hope that the wear will start to correct itself. The wear may be too severe to be corrected and you will have to live with it until you’re ready to replace them.
Getting it Done
If you are not able to do the tire rotation yourself, try to make friends with a local mechanic who is willing to rotate them based on your direction. They may be skeptical and not want to assume any responsibility for tire wear based on your rotation requests, but they won’t guarantee less wear with their rotation pattern either. Just find someone who is reasonable, it’s your vehicle. If you rotate your tires when and how the wear pattern dictates, you will get many more miles out of a set of tires, which will save you a lot of money during your ownership of the vehicle.
