THIS VEHICLE PICKS UP SMALL STONES BETWEEN THE REAR BRAKE CALIPERS AND THE WHEEL RIMS. THIS CAUSES A LOUD GRINDING NOISE, AND UPON REMOVAL OF THE WHEEL THE INSIDE OF THE ALUMINUM RIM IS FOUND TO HAVE DEEP GOUGES IN IT WHERE THE STONE WAS GRINDING. IF ENOUGH STONES RUBBED HERE, IT COULD CAUSE THE TIRE TO LOSE PRESSURE THROUGH THE RIM, OR IF THE STONE ROLLED UP JUST RIGHT, IT COULD CAUSE AN EXPLOSIVE CRACK AND DEFLATION OF THE TIRE POSSIBLY CAUSING LOSS OF CONTROL OT THE VEHICLE. I CONTACTED MY DEALER WHO SAID THEY HAVE HAD SEVERAL VEHICLES WITH THIS PROBLEM, AND THAT GM IS GOING TO HAVE TO DO SOMETHING TO ADDRESS THIS PROBLEM, BUT AT THE PRESENT THEY HAVE DONE NOTHING. I ALSO CONTACTED CHEVROLET, AND THEY SAID CONTACT THE DEALER, THERE IS NOTHING THEY CAN DO. MY WIFE AND CHILDREN USE THIS VEHICLE FOR A SCHOOL BUS, AND I AM VERY WORRIED ABOUT THEIR SAFETY, AND THERE SEEMS TO BE NO RECOURSE FOR THIS ENGINEERING DEFECT.*AK