Ok, I’m a big guy, and I sweat a bunch when I ride.  Normally, if my ride starts to go over the 3+ hour mark in the summer, my legs start to cramp and stop functioning.  I’ve tried several different sport drinks and whatnot over the years, and nothing ever seemed to help.  But this summer, I’ve started using Camelbak Elixir.  Just drop 4 tablets into my 100 oz. Camelbak bladder, and I’ve got all the electrolytes I need, without all the sticky sugar that I don’t need.  Just enough flavor, and doesn’t leave an aftertaste in your Camelbak.  I recently was on a 5 hour mountain bike ride at Brown County State Park in 90+ degree heat, and this stuff did the trick!