You might think that the most popular question car owners have about tires is how to know which tires to buy. A more pertinent question is how to know when to replace car tires. Do you know? The most obvious indication that it is time to get new tires for your car is when the tires experience a blow out. There may be times when accidents or road debris lead to a blow out and those cases are impossible to avoid. However, many blowouts are a result of driving on tires that should have been replaced. This is what you want to avoid. If you are making regular inspections of your tires you should be looking for signs of damage so that you can replace your tires and prevent a tragedy. Look for tears or gashes in the tires. Watch for cracks in the sidewalls or rims. If you experience a small puncture, you can probably have that repaired , but with larger gashes or holes you need to replace the tire. Keep in mind that the more gashes and repairs on a tire, the weaker it becomes. There are two things to look at when you're inspecting the tread of your tire. The first is level of wear. Newer car tires probably have a wear indicator strip built in. When it is visible, replace the tire. If it doesn't have a strip, you'll need to measure the tread yourself. Some tires have different recommended wear guidelines, but the accepted rule of thumb is that tires should be replaced if their tread falls below 1/16th of inch or about 20 percent of their original tread. Many drivers use the penny test as a way to measure tread, but it's probably safer to use an actual measuring tape or ruler. In addition to the depth of the remaining tread, you need to look at the pattern of tread wear. If the tread on your tires is wearing unevenly, they will not perform properly. However, in this case simply replacing the tires may not solve the root problem. Uneven wear may be the result of improperly inflated tires or a problem with the alignment of your vehicle. The first problem is easily rectified by developing better habits with regard to checking your tire pressure and making the appropriate adjustments. The latter problem may require a trip to the mechanic. Remember that the best way to extend the length of your tires is by taking proper care of them. Maintaining proper tire pressure, having the tires rotated and balanced regularly, and getting any minor damage repaired immediately will extend the life of your tires. However, once any of the above signs appear, it's time to buy new tires. It's not worth risking the chance of a serious or even deadly accident.