Is Washingtons quarter a safer measure of tread depth for tires driven in dry road conditions?
Following Tire Rack’s report on the negative influence insufficient remaining tread depth has on a tire’s wet braking distances, “What Honest Abe Doesn’t Tell You About Minimum Tread Depths”, some drivers felt our report was incomplete because it didn’t examine a shallow treaded tire’s positive influence on performance in dry conditions. So we felt it was appropriate to conduct a series of dry braking tests to round out our evaluation. Testing the Premise We used one of Tire Rack’s 2006 BMW 325i test cars equipped with 4-wheel vented disc brakes and an Antilock Braking System (ABS). The BMW was fitted with same tires we had run previously in the wet braking tests, the 205/55R16 91H-sized Michelin Energy MXV4 Plus previously used as Original Equipment (O.E.) on some BMW 3-Series cars. One set of test tires remained at the full, 10/32″ of original tread depth, while additional sets had been shaved to nearly 4/32″ (easily measured using a Washington quarter) and 2/32″ of remaining tread d
