I’ve written before about low risk practical measures to maintain your vehicle such as changing the headlights and taillights. Today we will discuss two fundamental principles of wheel care: tire pressure and alignment.
As part of my routine car maintenance, I typically check my car’s tire pressure to make sure that they are properly inflated. Insufficient air in the tires will result in decreased fuel economy and uneven wear. Overinflated tires will also result in uneven wear on the central treads. Tire pressure maintenance is particularly important in cold weather, as air pressure decreases as the molecules slow down with decreased temperature.
The first step in management of tire pressure is to know what is a normal number for your car. Most cars will have a detailed chart on a sticker in the frame of the driver’s side the car:
Many vehicles will have different ratings for the front and the back tires depending on the expected load. The photo above shows that my 2006 Subaru Impreza has a recommended tire pressure of 33psi in the front tires and 20psi in the back. Note that the tire pressure in the spare tire is much higher (nearly double) that of the standard tire. Since the spare tires are typically smaller than the standard tires (less contact area), a higher pressure is required to hold up the weight of the car.
Newer vehicles actually have pressure sensors built into the valve stems of the car and will notify the driver whenever the tire pressure is out of range. If your car doesn’t have sensors, then all you’d need is a tire pressure gauge from any department or hardware store. To check your tire’s pressure, simply unscrew the valve cap and place the gauge to the Shrader valve.
To refill your tires, either add air via a pump at the gas station or use a portable tire inflator/starter.
Wheel alignment is a more subtle phenomenon that is critical in maintaining durability of your tires. Misaligned tires will wear unevenly. The key to measuring wheel alignment is to check the tread depth of your tires. The magic number is that you need to keep the tread depth to be thicker than 2/32”. To measure the tread depth, use a ruler gauge:
Or you can also use a penny to track the tread depth. Please the penny upside down in the groove of the tread and if you see Lincoln’s head, then your tread depth is <= 2/32”. Uneven tread wear will result in decreased traction on the pavement and decreased control during slippery road conditions.
Check every tread in your tire (outside to in), and see if the depth wear is even. I recently noted that my outer treads were worn asymmetrically with the inner treads. This results from positive camber, and means that I should look into my suspension or take my car to get the tires realigned. I take my tires to Walmart every 7500 miles to rotate (I get free balance and rotation since I purchased the tires from them), but clearly the mechanics never did note uneven tread wear on all of my tires. YMMV on discount service centers!