The best practice is to use the inflation pressure listed on the tire placard located on the driver's door or door jam. The tire placard includes the Original Equipment (OE) tire size and inflation pressure for the front and rear tires. The placard pressure is the best inflation pressure for maximum tread wear and handling.

Inflating to the pressure on the sidewall of the tire often results in overinflation which reduces treadwear and handling while making the tires more susceptible to impact breaks because the sidewalls will be too stiff.

The front tires on most vehicles are the hardest working tires because they turn and provide most of the stopping force when braking. On front-wheel-drive vehicles, they also transfer the engine power to the road, which increases the amount of wear. The front tires also carry the weight of the engine, which makes them wear faster.

By rotating the tires every 5,000 to 8,000 miles, drivers can even out the treadwear so they get the most mileage out of every set of tires. Failing to rotate the tire wears out the front tires faster and causes irregular wear on the rear tires of front-wheel-drive vehicles because there isn't a lot of weight on the rear axle. Regular rotation also ensures that the vehicle handles the same way on wet road conditions?

When the front axle has deeper tread depth than the rear axle, there is a bigger chance that the rear of the vehicle will lose control when turning or changing lanes on wet pavement. It's called oversteer and also resembles fishtailing where the rear of the vehicle swings out.

If the worn tires are installed on the front axle, the driver will feel any loss of control in the steering wheel when turning or changing lanes in wet or snowy conditions. This gives the driver the chance to brake and adjust the speed before the vehicle loses control.

When two new tires are installed on the front axle of a front-wheel-drive vehicle and the vehicle turns or changes lanes in wet or snowy conditions, the driver will not be able to control the vehicle if the rear tires lose grip causing it to spin out of control. There have been numerous serious and fatal accidents after 2 new tires were installed on the front axle of a front-wheel-drive vehicle and it lost control when operating in rain, snow, sleet and ice. The best, and safest, practice is to install the 2 new tires on the rear axle to prevent these type of accidents.

Installing 2 winter tires on the front axle of a front-wheel-drive vehicle results in the same condition so dealers will only install 4 winter tires on front-wheel-drive vehicles to prevent this hazardous condition.

No, it is not illegal but it is a dangerous practice mainly because the inside of the tire cannot be inspected. When an object like a nail or screw punctures this inside of the tire causing it to lose air, it can create damage that cannot be seen on the outside. While a plug from the outside may stop the air leak, it does not stop the internal damage from getting worse.

The best, and safest practice for repairing is to remove it from the rim so the inside of the tire can be inspected for any additional damage. If the tire passes inspection, then the internal damage in tire is removed with a special carbide cutter and then the injury channel is filled with a rubber stem. This ensures that water and moisture cannot reach the steel belts and cause corrosion which leads to a separation. The final step is to install a patch on the innerliner to prevent any air from leaking.

Patching a tire on the inside without removing the internal damage and filling the space with a rubber stem still allows moisture to reach the steel belts. This has caused belt separations that have led to several serious and fatal accidents. The only way to properly repair a tire is to remove it from the rim so the inside can be inspected before installing a patch and plug.

The shoulder and sidewall of the tire are the highest flex areas so they generate the most heat and movement with the vehicle is in motion. When an object punctures the tire in the shoulder, the edges of the steel belts are often damaged. This is a critical area in the tire and any damage can lead to a separation and tire failure. It's also a high flex area, like the sidewall, which means the patch on the inside of the tire may not last the life of the tire.

Restricting repairs to the crown area, or center of the tread, ensures that all of the damage can be removed and the patch will permanently bond with the tire. This restores the original condition of the tire and creates a lifetime repair. Repairing injuries in the shoulder and sidewall are not considered lifetime repairs so there is no guarantee on how long they will last or if any internal damage has created a condition that will eventually lead to a belt separation and blow-out when the vehicle is in motion.

Dealers install tires and wheels with the correct lug nut torque to keep them attached to the end of the axle without causing extra stress that leads to failure. When a lug nut is installed with too much torque, the stud can stretch too far and lose the ability to clamp the wheel to the axle. In most cases, it's microscopic damage that cannot be seen with the naked eye so the dealer has no idea of the stud is in good or bad condition.

When the lug nuts are installed with the proper torque, the torque check will identify any studs that have been stretched by a previous installation where an impact wrench was used to overtighten the lug nuts. The dealer will check to make sure none of the lug nuts have lost torque, which is a sign that the stud may be stretched and in need of replacement.

Every tire in the U.S. and Canada has tire wear indicators or wear bars in the major grooves around the tire. These wear bars are exactly 2/32 in height so when they are worn evenly with the tread on either side, the has less than 2/32 in tread depth and must be replaced.

Tire manufacturers mold triangles or other symbols on the shoulders of the tires to show where the tire wear indicators are located. By following the marking on the shoulder across the tire, drivers will feel the wear bars in the major grooves. As long as there is some distance between the wear bar and the tread on either side, the tire has at least 2/32 of an inch in tread depth, which is the minimum.

The best practice is to invest in a tread depth gauge so the exact tread depth can be determined. As the tire wears down and the tread depth decreases, it will eventually start to lose the ability to stop on wet pavement. In general, that process starts when the tires reach 4/32 so drivers should start planning for replacement when the tread depth reaches 4/32. By the time it reaches, 3/32, the plan for tire replacement should be in place so the tires are replaced before they reach 2/32.

When the tread depth is less than 2/32, the ability to stop, turn and change lanes on wet or snowy roads is severely compromised. Additional space is required to stop in less than ideal conditions while turning and changing lanes becomes more dangerous when the roads are wet or covered in snow.