Consumer Reports plans to put more weight on tread wear

Sept. 16, 2008

Tread life test results will influence the scoring when Consumer Reports ranks SUV and pickup truck tires in its November issue. In the past, tread life was tested and reported upon, but did not affect the final scores.

Speaking at the International Tire Exhibition and Conference (ITEC), Gene Petersen, program leader and tire test engineer for CR's automotive test center, said the magazine determined that tread wear should be included because of its effect on other performance parameters.

Tread wear will be evaluated on the magazine's UTQG (Uniform Tire Quality Grading) road course. In addition, the tires will be tested for 16,000 miles. The result will be a "tread life rating" that may or may not support the tire's UTQG rating and/or tread wear warranty.

Petersen also addressed the 2/32nds-inch versus 4/32nds-inch tread depth debate. He outlined the camps as Groupe Michelin, which supports 2/32nds-inch as the minimum allowable tread depth, and Continental AG and The Tire Rack, which say tires should be removed from service at 4/32nds-inch.

CR offered a third alternative. Based on testing tread depth with a penny (the top of Abraham Lincoln's head equals 2/32nds-inch) or a quarter (the top of Thomas Jefferson's head equals 4/32nds-inch):

"Consumer Reports says use the penny to determine when your tires are worn out and should be replaced, and use the quarter to determine when to start shopping for replacement tires."

Petersen said this 2/32nds-inch "grace period" gives consumers time to shop for the right price, model, size, etc. Increasing original equipment size proliferation, for example, makes it harder to replace the tires.

"(We're) on the verge of boutique sizing of tires to new cars," he added.

In its November issue, CR will rank all-season, all-terrain and winter SUV and pickup truck tires. Next year, more broad-line all-season and winter tires (S-, T- and H-rated) will be tested.

In 2010, CR will test ultra-high performance tires, specifically V- and Z-rated summer, all-season and winter tires.

ITEC is a three-day event partially held in conjunction with The Tire Society's 27th annual Meeting and Conference on Tire Science and Technology at the John S. Knight Center in Akron, Ohio.