Has anyone ever heard of this? Yesterday my brother called me from Discount tire with a problem. He had taken my sister in laws Chrysler Minivan in to have a flat repair and a tire rotation. Discount told him that they could not/would not rotate the rear tires to the front because the rear tires had more tread on them than the front tires. The Discount manager told him that Michelin did a study that said it was more important to have more tread on the rear tires to prevent hydroplaning on front wheel drive vehicles and that DOT is recommending this. (The tires do not need to be replaced as they have thousands of serviceable miles left on them.) My argument is this: most vehicles have abnormal wear on the front especially on FWD like cupping and uneven tread wear. I believe it is necessary to rotate the tires to keep tread wear even and to keep more rubber on the road in the front for turning and braking. Discount and Michelin have me baffled a this point. Any thoughts?