I just replaced the Bontrager Selects with Continental Grand Prix 4000's and I can't believe the difference. Honestly, the bike is faster and climbs better. I thought it might be the psychological factor, but on my short hop (25 miles) that I can make after coming home from work, I was almost a half an MPH faster and honestly it climbs easier. All this and it handles better and rides better. The Bontys were 700x25 and the Contis are 700x23. Expected them to be a little harsher, but they are better, and didn't expect to see any difference in performance, although I thought they would handle better. Is this for real?