Bicycle computers and lights are essential accessories, if you're going to ride long distances or in poor-visibility condidtions, but there are some things that you must always have, for any ride. I'm talking water bottles here, people. Water bottles.

The first water bottle I ever put on a bike was a plain, one-pint plastic bottle, with a pop-top and metal cage. The cage was held onto the frame by flexible metal bands. Eventually, the cage and bands rusted, staining the bike's paintjob....

These days, most bike frames have built-in fittings for mounting water bottles, usually on the seat tube and downtube. The bottle cages are plastic, and of standardized size, so there is no problem fitting them onto the bike. The bottles themselves have gotten larger: the last one I bought was a 2 pint bottle, and most bottle cages will even accept 1 liter plastic soda bottles.

All of this is important, because drinking enough water on a ride, especially in hot weather, will prevent dehydration, heat exhaustion, and heat stroke. Having succumbed to heat exhaustion before, I can tell you that it's not fun. Not at all.

Whenever I ride in the summer I carry two bottles on the frame of my bike: a 2 pint on the downtube and 1 pint on the seat tube. I keep them filled with electrolyte drinks, like Gatorade or Powerade, and I try to drink at least 1 pint per hour. On longer rides, I also wear a Camelbak water bladder. I only fill this with water, and I keep it clean. It's my backup water supply for rides going longer than 50 miles. Personally, I prefer the bottles; they're easier to clean between rides.

It's impossible to overstate the importance of drinking enough on a long ride. Between sweating and breathing, we lose a lot of water, and it's vital to replacethat water as it's lost. Make a plan for hydration, and stick to it.