Things I've learned:
- The importance of riding with water cannot be stressed enough. During an 11 hour mountain bike race in Pisgah Forest a couple years ago, my race partner and I decided not to stop and filter water into our hydration bladders because we thought we had only 45 minutes to the finish line. It would have taken us 45 minutes if we were hydrated, but we weren't. Instead, the last bit took us almost two hours. Tongue was dry, blood was thick, heart was racing. Scared the shit out of me. I was so thirsty, I sucked the sweat out of my helmet's headband - no shit. I took foot-long steps while pushing my bike on any grade steeper than horizontal. Riding was out of the question. Never ever ever ride without water.
- Too much water is very, very bad. Drinking too much water can upset your electrolyte balance.... it literally waters down your body's electrolyte concentration. There's no such thing as 'overhydrating' - don't do it.
- If you're not peeing about every hour or two, drink more water.
- For me, the best drink mix for long rides (4 hours plus) is Hammer Nutrition's Perpetuem. It gives my racing partner stomach cramps.
- Friends I race with swear that vinegar helps reduce cramps. If you run out of Gu or Sport Legs, pickles and mustard contain vinegar and can be found at just about any convenience store.
Every body is different. What works for one may not work for someone else. Get to know your body and always carry what you need to get through a ride.