Ask The Car Chasers: When does a car need new tires?

Keeping good tires on your car could mean the difference between driving safely or experiencing a catastrophic accident. Knowing when to change them is a vital part of proper maintenance, but how do you know when it's time?

We put the question to Jeff Allen, owner of Flat 12 Gallery and star of CNBC Prime's "The Car Chasers." He shared many tips and warning signs to lookout for as an indicator of when your car needs new tires.

One easy way is to check by a visual inspection of the wear bars the factory has placed in the middle of the tire tread. These bars, which run perpendicular to the tread, are barely visible when tires are new. But as you pack on the miles, the wear bars become more visible and once they are level to the tire tread, it's time to get new tires.

Another easy method is to grab a penny, turn it upside down and stick it into the tread to measure its depth. If the president's head is covered up by the tread, then your tires are fine. But if the president's head is visible, then your tires are too worn and need changing.

Michael Bodmann | E+ | Getty Images

"The tires are designed nowadays to do 50-60,000 miles. But when they get down to those wear bars, you don't have as much tread," Allen said. "And I recommend right when it gets down to those bars, you replace your tires."

Other factors that you should be on the lookout for are weather cracking and sidewall integrity. As tires either age or are exposed to extreme weather conditions, the rubber begins to lose elasticity and cracks appear on the surface. Some cracking might not mean you need new tires, but if you notice a lot of splintering, it's a good idea to take your car to a tire shop where a professional can help you determine if you need new tires.

You should also be on the lookout for any noticeable cracks on the tire sidewalls. And if you see any abnormal bulges or bubbles, take your tires to a shop immediately.

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Another simple, yet often overlooked factor people might not consider is that tires actually have an expiration date, Allen said.

"Most people don't realize that tires actually have a date code and can simply need to be replaced due to age."

A good rule of thumb is to strongly consider changing the tires on your daily car every six years, or at least have them checked out by a professional after this length of time.