Weigh yourself after your ride. If you're a few lbs lighter, you're doing it wrong.

Whoa, that's a lot of water. I can't even imagine drinking that amount of water within the 1.5-2 hours it would take me to ride that distance.

Most of you guys are staying hydrated before your rides, right? Don't just drink while you're on the bike -- that's too late (unless you're going to be spending a few hours on it anyway). Get a head start by drinking hours beforehand, or even the night before. Chug a liter of plain water before going to bed, for example.

Dick's sells them buy the gels

Yeah this does make a difference. I generally try to drink a full bottle of water before I leave. Then I can comfortably sip water occasionally throughout the ride. Sometimes I'm in a rush and I forget to drink water beforehand...I end up drinking most of my water less than halfway through the ride and am forced to "ration" my remaining water for the rest of the ride, which is pretty miserable.