Tire Basics 101

Most folks don't know much about tires. Most people seem to think that they are round, black, rubber things that the car/truck has to have that costs too much. What you may or may not realize is how very different and very important tires are. They are the single points on your vehicle that must maintain contact and traction on the road.

If your engine is running well, transmission works as it should, the vehicle won't handle  as well as it should if the tires are not the right type for that vehicle. There can be too much flex in the sidewall during “spirited acceleration, braking, or cornering”. The tire may not have the capacity to handle and hold the weight on heavier vehicles.

One of the first things a tire salesperson should ask you is what are your driving habits. Next, do you put snow tires on in the Winter? Snow traction tires have very different features than Summer or all season tires. What did you like about your current tires? What didn't you like? This will help the salesperson narrow down the best options for your driving habits.

Tires have different tread patterns for different uses. The basic design will consist of  several things: water channels (to help displace water), varying tread block types and sizes (to help suppress noise and improve traction), and siping (for additional traction).

Tires have different sidewall construction and can offer a number of benefits. Some are: less flex on turns, more stability when loaded, comfortable ride and styling.

The heart of any tire is the inner liner. Its job is to give the tire shape and hold in the air. Wrapped around the inner liner are fabric belts. Fastened to the bottom of the fabric belts is the bead, which holds the tire to the wheel.

Let's talk about tire size. Most tire sizes start with either a 'P' or an 'LT'. This tells us if it is a passenger or light truck rated tire. The light truck tires have a higher load capacity.

The next number is the approximate width of the tire, then is the aspect ratio or the height of the tire. Lastly is the rim or wheel size. The best part of the whole tire is the next number and letter combination. Usually a number which indicates the tires load capacity, and then the letter that tells the speed capacity of the tire. I like to call it the performance rating since most cars are not even capable of handling the speed that the tire can handle.

A few years ago there was a pretty well known case of tires that failed and there were several deaths associated with it. My perspective on the case was this: The tires were underinflated based on what they were designed to be run at. Most of the rollovers occurred in hot climates. The resulting failure was due to heat build-up in the sidewalls due to road conditions, under inflation (based on design) and outside temperatures.

Tires should be rotated at various intervals, depending on manufacturer recommendations. A good general guide would be about every 6,000 miles. This is very important on all wheel and 4 wheel drive vehicles.

Proper tire inflation is very important for handling, load carrying ability, and fuel economy. Tire pressure should be checked at least 1 time each month. 

Andy Cotey is the manager of Hockett & Olsen Automotive on Bainbridge Island. He has been in the automotive industry for over 20 years. He can be reached via email at- hoauto@msn.com