The 2014 Camaro Z/28 is the most track capable Camaro ever built, able to pull massive g-forces in the corners and in deceleration. However Chevrolet engineers found the sticky Pirelli Trofeo R tires were providing so much grip and the carbon-ceramic Brembo brakes were so powerful, the tires were slipping around the rim.
The engineers drew on one of the wheels and tires before the beginning of the lap with chalk relative to where the valve stem was on the wheel. After a hard couple of laps out on the track, the line they drew on the tire had shifted away from the line on the rim, signaling that the tire had rotated at least a full 360 degrees during track testing.
To remedy the problem, the team used a trick common in road racing. The bead of the wheel was blasted with a special gritty material, which gives it a rough, textured surface and prevents the tire from slipping and moving around the rim.
“Media-blasting the wheel created an extremely aggressive grit on the rim, which finally got the tire to hold,” said Mark Stielow, Camaro Z/28 program manager.
Chevrolet released a video explaining the problem as well as the media-blasting technique which solved it. Check it out just below.
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Interesting. The same problem existed in the 1960’s-1970’s with chrome plated wheels made by Motor Wheel as R.P.O.’s for Buick. Their high torque engines and unexcelled brakes made the problem show up on Buicks more so than on other vehicles using our chrome-plated wheel rims, notably Chrysler products, Ford Mustangs, etc., that used out Magnum 500. To remedy the situation, we simply painted the bead seat areas with a black paint. This added a couple of thousandths of an inch of bead rubber compression as well as increasing the coefficient of friction between the tire and the wheel. Grit blasting wheel rims at 600 an hour would have been a real problem!