Tires 101: Consider these tips to keep the rubber safely meeting the road

We know that tires, the only car parts that touch the road, are crucial. We know tire pressures should be checked regularly, something that only about one in seven drivers do. The www.tiresafety.com website can help the 85.7 percent of regular non-checkers - if they sign up for monthly e-mail reminders. Here are some other reminders about tires.

Tire types - Almost all passenger cars today ride on all-season radials. They eliminate the need for winter, or snow tires, which perform better on ice and snow but wear faster on dry surfaces. Winter tires are now used mostly by people who want to save their performance or low-profile tires, which handle and grip better but cost more, wear faster and sacrifice ride comfort.

Because there's more detail on light truck tires than space here, follow automakers' and tire experts' advice about SUV, minivan and pickup tires.

Sidewall hieroglyphics - After the brand name, tire line and any model number, what do sidewall alphanumerics mean? "P215 75R16" tells you a passenger tire is a 215 millimeter-wide radial with a sidewall 75 percent as tall as the tread width and a 16-inch rim size. Truck tires use LT; a number like 230 offers greater road contact; B (belted bias) and D (diagonal bias) rarely replace R now; and 50R would be a performance tire)

In the performance rating - e.g., "95S" - the number code tells you how much weight a tire can carry - once you consult the Maximum Load-Carrying Capacity Per Tire Chart. The speed rating letter, commonly S, could be T,U, H and V (gradually more speed). W, Y and Z appear on performance tires. "M+S" means a heavy snow-rated tire. Other sidewall information includes:

Temperature (A best, C mandatory), traction (AA best, C lowest) and treadware ratings. The industry treadware standard is 100; lower numbers mean faster wear, higher numbers mean longer lasting tread.

U.S. DOT 12-digit serial number identifying where and when a tire was made.

Maximum load and tire pressure numbers.

For more information, visit sites like www.tirerack.com or www.edmunds.com.

The "right" tires - Many factors determine what tires a vehicle can "wear," so consumers should rely on carmaker's guidelines and tire pros' recommendations. The wrong size can affect anti-lock brake performance.

Care - Tires cause a third of all breakdowns and most fail when tread is low, so check tires monthly and before long trips for damage, smooth spots and uneven wear (underinflated tires wear at the edges, overinflated at the center). Avoid jackrabbit starts, squealing and curbs; rotate tires every 6,000-10,000 miles; and align front ends annually.

Inflation - Tires' worst enemy is underinflation. It causes premature wear and loss of control and wastes gas. Every pound per square inch (psi) that a tire is low raises fuel consumption 0.8 percent. Because tires lose about 1 psi each month and with every drop of 10 degrees F., and because they look OK even 10 or more psi low, they need to be checked monthly when they're cold (spares, too). Overinflated tires have less road contact, ride rougher and are more likely to rupture when they hit something. Use carmaker inflation guidelines (on door jamb stickers, in owner's manuals), not the maximum pressure number on the tires because the carmaker's number is designed for that vehicle's suspension system.