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Actually, when I googled the "quarter test for checking tires" there were several articles that indicate the "penny test" may be outdated and unsafe. I haven't seen any commercials, but here is a 2009 article from WheelKraftNW
Quarters are safer than pennies when it comes to checking your tires, according to new tests conducted by Tire Rack, the countrys largest independent tire tester. With much of the winter driving season remaining and change of season ahead now is especially important for drivers to be aware of their tires condition.
For decades the tire industry had taught drivers to use the so-called Penny Test as a simple way to tell when tires were worn out. But experts at Tire Rack say that popular lesson is outdated, compromises safety, and should give way to the Quarter Test.
In the old Penny Test, seeing the top of Lincolns head while holding a penny upside sown in a tire tread grove indicated a tread depth of 2/32-inch (1.6mm) or less, and that the tire needed replacing (to learn how to properly get directions on this go to
www.tirerack.com/treaddepth).
In driving tests, a late-model pickup truck on tires that passed the Penny Test, (legal in most states) averages 499.5 feet to stop from 70 miles per hour on wet pavement. That is equal to about 12.5 school buses or nearly a tenth of a mile.
The same vehicle riding on tires that passed Tire Racks proposed Quarter Test stopped almost 122 feet (24%) shorter. These tires had treads measuring 4/32-inch (3.2mm) deep, as measured from the edge of a quarter to the top of Washingtons Head. Not only were braking distances reduced, overall grip noticeably improved!