How do I know when it's time to change my tires?

You will know because, you will lose handling, grip, and any kind of control you once had with your car. You will feel every bump in the road. The tread on the tire will be gone. Don't wait so long that your tires look like pancakes. Also, when tires get old, they seem to pick up things like nails, screws, and other sharp objects that could give you a flat tire more often. You can use a penny also to check your tires. If the penny know longer will fit in the tread of your tire, than it is time for knew set.How do I know when it's time to change my tires?
when they fail inspection like mine just didHow do I know when it's time to change my tires?
If you look closely between the treads, you will see bars between them, those are indicators that the tires are truly worn out if worn down t to those bars. Most drivers replace there tires before they hit those wera bars and I recommend it too. Also, usually the edges of the tires wear first, from cornering etc. Don't drive them till the cords show, very dangerous.
Use Scott's answer. That's the same thing I tell people too. It is 3/32'; tread depth. Your tires may also have a wear indicator built into the tire. When the tires get too old, a colored stripe will be visable when you look at the tread.



Good luck.
Just like in the commercial, take a penny and turn Lincoln upside-down. Put the penny in the tread. If you see the top of Lincoln's head, it's time to get new tires.
Take a penny and place it inside the threads,if you can see lincolns head,change them
when there are creases in the tire or if it don't ride good or it looks like crap
I knew it was time, when my tire squeel annoyingly during normal driving, and the indicator bar-across-thread is nearly thread level.
when the thread feels smooth because you're suppose to feel ridges
general rule of thumb, use a penny, upside down in the groove on the outer most tread. if you can see the top of lincoln's head, it's time for new tires.