I have two Ultras, one uses 402 MT90B16-72H and the other one has a 404 130/90/16, both Dunlaps. I've always got twice the mileage out of the front tire than I got on the back. I check my tire pressure before each ride. I was out checking my tires today and I noticed the front tires were about gone at 5K, but the rear tires still have about 4K left on them, on both bikes. The front and rear tires were put on at the same time. Has anyone else had this problem?? I've been riding for about 40 years and the only time I've seen this happen is on the skinny 21" tires. Do you reckon I got a bad batch?