We started using the Gatorskins(700x28) last fall, after the Ultra 2000s were discontinued. Our front tire has 4500 miles on it. I replaced the first rear at 2000 miles. The current rear has 2500 miles on it. I will be replacing both this next weekend. We had our first flat with these when we picked up a small sliver of glass Saturday in the front. We are running the Specialized 700x20/28c tubes. Some feel that these are too thin but we've been using them for almost 30,000 miles with no trouble. Our team weight is under 300lbs.