We returned the rental today and asked how much and lead time to order. They pulled it up on the computer and said, "not available." Went to a second shop and they couldn't find one either, but couldn't decide if I should order a 50 or 52. Called my regular bike shop and they said I needed a 52 and they had one on the floor. My current Trek is a 50 and hubby thought the 50 Madone looked right. This is why I didn't want to go bike shopping! I'm headed out of town until Tues, then a preliminary fit at one shop on Wed. If he says 52, I'll go back and see if the other 52 is still there. I'll keep you posted on those tires. There won't be any negotiating anymore!