Hey KTeach

I'm a mtb-er, but used to road ride as well (can't beat the thrill of the downhill!). I've done many many rides over 4 hours in duration without needing a pitstop, and I'll drink 2-3 litres on such a ride. I put it down to what I'm using - it's an electrolyte and carbohydrate drink (don't know if you have it - it's called 'replace' over here, made by horley's). Apparently the electrolytes help (my story, sticking with...)

It could also have something to do with the fact that I refuse to lose time by stopping and eventually the need just goes away, or if I'm near enough to the finish line (in a race) it gives me extra motivation to find that extra effort

My first suggestion though, would be to try out different hydration formulas.

Good luck!