Propickup Digital Magazine
Issue link: https://read.dmtmag.com/i/105105
Winston de Wardt drew the short straw as the primary tire changer while Bridgestone's Adam Kaempf gave a helping hand during the pit stops. Vericom VC2000 computers collected the test data on every run. PRE-TEST BREAK-IN We had the tires shipped to our Alabama office, where we put them on a 3/4-ton GM 4x4 diesel crew cab and ran each set over the same 100mile section of interstate. This dry run rid the tires of release compound and opened up the sipes. Release compound is like a lubricant and would have definitely affected our performance numbers if we tested the tires right off the rack. Sipes, those tiny cuts in the tread blocks that grip snow, also require pavement scuffing to open them before hitting the snow. After break-in, two sets of tires were re-mounted on 17x7.5 Accuride OEM steel wheels to fit GM heavyduty pickup's new 8-on-180mm bolt pattern. We used one set of ProComp 6032 alloys for the third set. The mounted tires were then shipped off to Colorado. THE TEST heavy-duty 4x4 diesel pickup was a "first" for them. That made our snow tire shootout that much more fun for everyone involved – except maybe the poor guys who drew the short straw to be the official tire changers. As for the test itself, we invited nine of the big-name snow tire manufacturers to participate, and encouraged them to send a tire engineer along to participate in the actual tests and offer insight related to their entry. Michelin, Hankook, Cooper, Toyo, Continental, BFGoodrich, Bridgestone, Nokian and Goodyear received multiple invites. Only three stepped up to our tread-to-tread challenge: Bridgestone, Nokian and Goodyear. Goodyear's SR-A all-season light-truck tires came on our 2011 GMC Sierra HD Crew Cab and served as our "control tire." (A control tire is run at the start of a test, mid-way through, and at the end so any changes in the track surface condition can be factored into the numbers.) Our tire shootout is very straightforward: Each set of tires is tested and scored both objectively (computer data) and subjectively (personal observations) in three areas: acceleration, braking, and handling. The acceleration and braking tests are run on a flat 300-foot section of the .9-mile road course and every test is recorded by a pair of Vericom VC2000 Performance Computers. Driving Sciences' test driver Kurt Spitzner, who is also an instructor at BWDS, is our designated wheelman. Mark "Mr. Charts & Graphs" Kuykendall, Bridgestone's light-truck engineering manager mans the brace of Vericoms. Spitzner accelerates the 7,200-pound Sierra Crew Cab diesel in 4Hi as quickly as possible to 30mph without triggering traction control and then stops it as fast as ABS allows. The VC2000s log G-force, time and distance every moment of the tests, which are done six times in succession for each set of tires. TEDIOUS TESTING Spitzner first runs the stock Goodyear SR-A "control" tires to establish a baseline for the surface conditions. The test team allows a two-minute propickupmag.com PROPICKUP 53