- Car Care & Maintenance
Tire Pressure and Maintenance
Inspecting tire pressure regularly and maintaining correct inflation pressure offers several benefits:
* A longer service life for your tires
* Better gas mileage
* Better engine performance (and lower emissions)
* Improved car handling
* Shorter stopping distance
* Improved ride
* Better heat buildup control
* Proper tire deflection over road irregularities
* Better resistance against damaging potholes
These are some reasons that--since September of 2007--all vehicles under 10,000 pounds of weight come equipped with a Tire Pressure Monitoring System (TPMS) in the United States. The system alerts you when one or more of your car tires drop 25 percent below the recommended air pressure.
Even with the TPMS system in place, you don't want to be driving around with 15 or 20 percent below or above the ideal pressure. In the end, it all adds up. Furthermore, by checking your tires regularly, you may become aware of tire and vehicle mechanical problems that may put your safety at risk, as we'll see later.
How Do You Know You Have an Incorrect Tire Pressure?
In general, an over inflated tire will tend to bounce over road imperfections: uneven road surfaces provide a bumpy ride. And, you'll know you have one or more under inflated tires when you hear a squealing sound when turning a corner. Another sign of uneven inflation is steering wheel pull.
Nonetheless, a few pounds under or over the recommended inflation pressure can go unnoticed for a long time--especially on radial tires, which can hide low inflation pressure. Underinflation allows the tire to flex more and build up extra heat. Overinflation reduces the tread area in contact with the road and resistance to damage. And you won't notice until one day, one or more tires have worn out too soon.
You can prevent improper inflation and its negative domino effect by checking and inspecting your car tires regularly. With a simple procedure you can correct pressure and check for revealing signs of potential trouble. Best of all, it only takes a minute or two. But first, you'll need a tire pressure gauge.
Tire Pressure Gauges
Tire Pressure Gauges
A tire pressure gauge is a common tire service tool. You'll find it at auto parts stores, auto and tire dealerships, and most department stores. Tire pressure gauges come in pencil (mechanical), dial, and digital configurations. Automotive experts recommend using either a quality dial or digital type gauge for accuracy.
Recommended Tire Pressure
Your car manufacturer gives you the correct tire pressure for your vehicle on a sticker found on the driver side doorpost; sometimes a sticker inside the glove compartment or your car owner's manual will have this information as well.
Regardless of the tires, you also can figure out the proper inflation pressure by reading the information marked on each tire's sidewall. The marks on the outside wall of each tire include the maximum inflation pressure for that particular tire. It'll say something like "300 kPa (44 psi) MAX. PRESS".
Remember that your tire sidewall gives you the maximum inflation pressure for that tire. However, the recommended inflation pressure falls between 1 and 3 pounds below this mark. For example, if the maximum inflation pressure indicated on the sidewall says 35 psi, your recommended inflation pressure will be between 34 and 32 psi. This allows for internal heat buildup as the tire's surface rubs against the road. So, if you inflate this particular tire to 32 psi, you'll be at a safe inflation pressure.
Checking Tire Pressure
Once you have your gauge and the recommended inflation pressure, it's time to check your car tires.
1. Whenever possible, check tire pressure early in the morning, when the midday heat (during the summer months) hasn't built up, and before you've driven your car. If you just drove your car, even for a mile, allow the tires to cool for a couple of hours to allow internal tire heat to dissipate.
2. Look for the stem valve on the tire and unscrew the cap. Press your tire pressure gauge squarely against the valve. You will hear a momentary hissing sound (air coming out) as you press the valve. If the hissing doesn't stop, you are holding the gauge at an angle. Just remove the gauge and try again. Then read the pressure indicated on the dial, display screen or graduated stick that slides out the bottom of the gauge, depending on the gauge you are using.
3. Compare your gauge reading to the recommended pressure and make a note of the number of pounds you'll need to adjust air pressure to, if necessary. If your reading is too high, use the gauge to release air pressure from your tire by slightly pressing the gauge fitting at an angle against the air valve.
4. Replace the valve stem cap
5. Check the rest of the tires, including the spare tire.
6. Then, head over to the gas station to adjust air pressure as necessary. Use your gauge to verify each tire has the right amount of air.
Inspecting Your Tires
While checking tire pressure, take a moment to inspect each tire:
* Run your hand along the tire's sidewall and tread surface and look for distorted areas like bulging (on the sidewall), cupping (over the tread surface), cuts, cracks, or missing chunks of tread. If necessary, take your car to a tire shop to determine the source of damage and fix potential problems.
* Check the tread area for abnormal wear patterns. For example, you may notice the center or outer sides of the tread area wearing out faster than the rest of the surface. This may be an indication of inflation, alignment, wheel balancing, or suspension problems.
* Then, check for tire wear. Locate the small wear bars that run across, between one tread block and the next. Tread block height should be taller than the wear bars. If the tread surface has reached the same level as the bars, you'll need to replace the tire. On some tires, the wear bar will show up as a wide, solid rectangle running across a section of the tread area. You can watch the next video to get a visual rundown of an inspection procedure, including location of the wear bars.
Tire Safety Inspection
Check Your Tires For:
* Proper inflation
* Missing chunks of tread
* Abnormal wear patterns
Automotive manufactures recommend checking inflation and physical condition of a car tire at least once a month since changes in outside air temperature (and altitude) affect tire pressure. On average, a tire loses between 1 and 2 psi of pressure for every 10 degrees of ambient temperature variation. Also, tire and vehicle mechanical problems can develop without a warning.
Adding tire pressue and tire inpseciont to your rotation and balancing schedule will help you maintain an improved--and safer--riding experience. Besides, inspecting your tires regularly can give you time to correct potential problems at a much lower cost.