TIRES: More to tread than meets the eye!


Despite technological advances, tires still wear out and will need to be replaced several times during the life of your vehicle. Here are a few tips to maximizing your tire investment. The side wall of the tire is printed with specific and useful information. Key to our discussion here:

Tire Pressure

Maximum tire pressure and load ratings: It's a bit trickier than just reading the number!

Example 1: The sidewall says "35 psi @ max load 1090 lbs."

What this really means is:

*A note about on board tire pressure sensors: Vehicles 2006 and newer are required to have on-board tire pressure monitoring systems. While these systems differ by manufacturer, they may only alert you if a working tire or spare is flat, or if there is a significant difference between the pressures on all working tires. If working correctly, the purpose of the system is to alert the driver that a tire is losing air, but has nothing to do with correct inflation pressures for your vehicle and use!



That's why Perfect Timing Auto is here to help!!

Tread wear, traction and temperature ratings

This information is found on the Dept. of Transportation (DOT) panel embossed on the side wall of the tire.

These numbers are assigned by the tire manufacturer and are only relative to other tires they make! The higher the number, the longer the tire is rated to last. Keep in mind though, it's rated to last longer because the rubber used is harder, making the tire louder and the ride harder!

The rating is based on the tire's ability to stop a vehicle on wet concrete and asphalt in a straight-line situation, "AA" being the best. It does not indicate the tire's cornering ability.

The rating is a measure of how well the tire dissipates heat and how well it handles the buildup of heat. Excessive heat buildup can reduce tire life, or even lead to tire failure. However, while temperature plays a role in the speed capability of a tire, it is not the only factor.

Manufacture date

Look for a date within a year prior to your purchase date, the newer the better!

Rubber is not a fine wine; it doesn't get better with age! The older it gets the more likely it is to harden and crack, reducing the life of your investment!

Speed rating

This is a complex topic rooted in a German concept of a tire's ability to perform with minimal distortion at high speed on the Autobahn. In the US, we have speed limits and regardless of the Speed Rating, it's somewhat irrelevant to rate a passenger vehicle tire above legal US highway speed limits. However, the Speed Rating does factor into the longevity of the tire, calculated as a percentage of wear at the normal speed you drive. In general, selecting a tire with a higher speed rating will give you the best handling and wear.

Example: 225/50R16 89S - "S" is the Speed Rating, in this case, 112 mph.


DOES matter- a lot! While it may be cool or trendy to oversize, or even undersize your tires, it is not a "healthy choice" for your vehicle! Your car comes with manufacturer recommendations for tire size. This is based on the complex engineering design of your vehicle, and factors in not only the tires themselves, but wear and performance of other structural components such as axles, brakes, fuel economy, and even the speedometer accuracy!

Nitrogen gas in the tires

It's a common myth that filling your tires with nitrogen is better than good old air, supposedly because nitrogen molecules are larger, so they can't leak as readily. Air is approximately 78% nitrogen anyway, and filling with nitrogen may give a false sense of tire inflation security. Tire pressure should be checked at regular intervals, at least every 3 to 5 thousand miles, regardless of what they're filled with. In any event, why pay to have your tires filled with nitrogen when everyday air works just as well!

Check for wear

Modern tires are required to have tread wear indicators. In most states, tires are legally worn out when their tread depth reaches 1/16 inch (or 2/32 inch as found on standardized tread-depth gauges). "Balding" tires are a risk not only for tire failure, but can also the car's braking, cornering and traction abilities - all critical for safe driving!

Here's a handy tip to monitor tire wear if you don't have a gauge: Place a quarter upside down in a tire groove. The distance from the coin's rim to George Washington's hairline is about 1/8 inch. If you see all of his head in any one groove where a tread-wear indicator appears, start shopping for new tires.


Clearly, selecting and maintaining tires is a not a simple matter!

At Perfect Timing Auto, we're here to help!! TIPS ON AUTO CARE AND MAINTENANCE