Back in March when I got back on the bike it was tough to do 7 laps around the local schools track around the football field. Currently I am up to 18 miles as I get in better shape and lose some weight. Even though my engine is getting better I keep reading different posts about how much farther and faster people are going on new road or performance hybrids as compared to their comfort hybrids. My current ride is a Fisher Zembrano and a new bike at this time is not possible. The biggest mod that I keep hearing to lower some weight and give a boost in speed is to go with a more narrow tires. The Zembrano came with 700x35c Bontrager Invert Hardcase tires and I am wondering if a 32 or 28 would make that much of a difference if they would even fit the wheels. Should I even bother with trying to make changes to the bike and just keep working on the engine until I can move up to a better machine. Don't get me wrong I am enjoying the bike I have but I keep hearing things like "If you can do 20 miles on a comfort hybrid you can do 30 or more on a road or performance hybrid. " Any other suggestions?

http://www.bikepedia.com/QuickBike/B...rano&Type=bike