Keep older tires on front wheels


This is from a service that supplies expert witnesses to attorneys for trials, and it runs counter to what I had thought –

TIRE REPLACEMENT
NEW TIRES ON THE FRONT OR BACK?
Introduction Tire maintenance is an important part of vehicle safety, everything a vehicle does: go, stop, and turn, is directed to the roadway through the tire footprints. In an ideal world, all tires would be rotated often, about every 5,000 miles, and all tires would wear evenly and wear out together. Then a new set of 4 tires would be purchased and installed. The cycle repeats.

QUESTION: In the real world it is common for a vehicle to need only two tires replaced at a given time; in this situation, where should the new tires be installed?

SHORT ANSWER: Newer tires should always be be installed on the rear of a vehicle.

Long Answer In the event of a loss in control, the vehicle does not go in the manner or direction the driver intends. In some cases, the front tires lose traction. In this event, the vehicle understeers, it turns less than the driver intends. Sometimes this results in the vehicle traveling to the outside of a curve and sometimes even going off the pavement. In an understeer, the natural reaction of the driver is to lift off the gas and turn a little sharper. Both of these reactions will often bring the vehicle back under control.

Sometimes, the rear tires lose traction. In that event, the rear end swings out causing the vehicle to yaw. This action often occurs very fast and requires quick and precise countersteering by the driver to correct. Unfortunately this condition is outside the experience of most drivers and rarely can an oversteer be corrected. This often results in a crash.

Therefore, it is always preferable to have a vehicle lose traction at the front than to lose traction at the rear. This is how all vehicles are designed. They all have some built-in understeer.

If the front tires and rear tires are different in age, or tread depth, it is important that the better tires always be mounted on the rear wheel positions. This will maintain a safe handling condition of the vehicle. This seems counterintuitive because sometimes it seems that the better tires should be installed on the harder working front wheel positions, but that can result in an unsafe oversteering condition.

Another reason to install new tires on the rear is that new tires have a smaller chance of failing than older tires. Just as the rear tires need to have better traction to maintain a controllable vehicle, a vehicle with a rear tire failure is much harder to control than a vehicle with a front tire failure.

Therefore, it is always necessary to ensure that the better tires on a vehicle are mounted on the rear wheel positions. This applies to any 4 tire vehicle. One-ton and heavier trucks that have dual rear tires have more to consider.

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