Tire Pressure: Always check your tire pressure . Driving on underinflated or overinflated tires, particularly in hot weather, causes internal tire damage and increases the chance of a tire failure by tread separation or blowout. Tire pressure should be checked every few weeks, and certainly before a road trip. If possible have them checked at a tire service center, but always check the pressure before driving on the tires or after they've cooled; otherwise your tires will be hot and your pressure reading won't be accurate. Lastly don't confuse the maximum tire pressure listed on the sidewall of your tire as the recommended inflation levels. The manufacturer's recommendations for inflation levels can be found on the lower-inside driver's door frame.
Tread depth and appearance: In addition to tire pressure, be conscious of your tread depth and appearance. A tire should be replaced when it reaches 2/32 of an inch. That's about the equivalent of the distance from the edge of a penny to the top of Lincoln' s head. Fortunately, most tire manufacturers have included a tread bar in the grooves between the tread, so that you can feel with your own hands if you're nearing the 2/32nds mark. Also look for any uneven wear pattern on the tire, meaning that one edge might be more worn than the other. Keep in mind that as your tread becomes uneven or wears away, you're at increased risk of hydroplaning during summer thunderstorms.
Age: Lastly, be aware that tires deteriorate as they age and are more prone to sudden failure that can result in a crash. This applies to spare tires and tires that are stored or have had little or no use. Heat caused by hot climates (such as Florida) or frequent high-loading conditions can accelerate the aging process. In addition, most vehicle manufacturers recommend that tires be replaced after 6 years, regardless of the remaining tread depth . Check your vehicle owner's book to clarify. To determine the age of your tires, look for the code which begins with "DOT" on the side of your tire. The last four digits indicate the week/year the tire was manufactured. When purchasing a tire, request tires that are less than 12 months from the manufacture date.