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TIRE TESTS S The wet braking while turning stage was a test of how the tires interacted with both the ABS and the stability control. S The road course test was run clockwise, then counter-clockwise to even out the tire wear. more worn as-tested. The Goodyear changed much less in performance, new versus worn, simply because it wore less on the Charger and CVPI during the track testing. This raises the obvious request for ap- ples-to-apples testing: both tires with ex- actly the same percent of treat left, say 50 percent, or perhaps, both tires with the tread depth exactly touching the wear bars. The "take-away" lesson from this MSP test stage is really that tire wear definitely affects wet braking and wet braking while turning. Of course, that is why tires have tread in the first place. Tires Are Not All Equal Every major police tire test conducted in the past 20 years, including tests con- ducted by Police Fleet Manager with Tire Rack, and including this latest MSP test, have shown the same results: Just be- cause the tire fits the rim does not mean it should be used on an emergency vehi- cle. The brands that are used as Original Equipment are better in every way than most aftermarket brands – those generic, low cost, "whatever" tires from the local discount tire store. Just because the tire has the same speed rating as the OE tire does not mean it should be used on a pursuit- rated vehicle. Certainly, tires of lower speed ratings should never be used on police vehicles. The speed rating means more than top speed – it specifically re- lates to the internal stability, durability and integrity of the tire. Finally, come replacement tire, you are looking for "High Performance All- Season." While the All-Season label might mean all four seasons (but prob- ably not winter), the Touring label really means summer-only. Best bet? Put the OE tires back on. Sec- ond best bet? Select a tire that has done well in police-specific testing. The entire, 352-page report is available online at the MSP website. Just use "tire" as the search word. The Police Fleet Manager test results are also online. Go to www.hendonpub. com, click Resources, click Article Archives and search for "tire tests." (Ed. Note: The complete 350-page MSP 2011 Police Vehicle Tire Evaluation is available online at www.michigan.gov/msp – search for "tire." A summary of this MSP tire test is in the May- June 2012 issue of Police Fleet Manager, which is also online at www.hendonpub.com, click Resources, click Article Archives and search for "tire.") LaO Post your comments on this story by visiting www.lawandordermag.com T The static circle was run with the electronic stability control engaged, and then with it partially deactivated. www.lawandordermag.com 29