Consumer Reports' tire engineers Gene Petersen and Jennifer Stockburger said wet weather can be a big problem for tires, especially as they lose their tread. "As it wears, and gets very worn, a lot of those biting edges go away, and the channels don't have any depth so the water has nowhere to go," said Stockburger.
But Consumer Reports' newest tests show that even before a tire is completely worn, vehicles can take longer to stop on wet pavement. Cornering is also compromised. The tires just don't have the grip they had when they were new.
Consumer Reports has developed an easy way for you to tell if your tires are nearly ready to be replaced. "If you insert a penny upside down into the tread and you can see all of Lincoln's hair, that tire is legally worn out. We think a better test may be the quarter test. By doing the same thing and seeing all of George Washington's hair, you know that your tire has potentially compromised its safety and it gives you time to shop for a replacement before you absolutely need it," said Stockburger.
If you check your tires regularly the way Marta now does, you'll get an early warning that you need new tires.
Consumer Reports said just as important as checking your tire tread is checking for bulges, cracks, or cuts. If you find those, replace your tires.