I tried a energy drink mix (no plain water) on the bike once and had some very slight cramping. I didn't think much of it. A day or two later I did the same thing, only on a longer ride. Around 50 miles I started cramping. At 75 I got off the bike, called a friend and laid in the grass for 30 minutes. Could barely get off the ground and into the car.

Now I'll use 1 bottle of the mix for every 2 or 3 bottles of plain water. Seems to work fine, but not real sure of any benefit. Unfortunately, I have a bunch of the mix left over and hate throwing it away.