Both - Camelbak - ice and water, bottles (2-24oz)carbosugarstuff. If ride is under 20 miles, bottles - all water - over 20 miles but under 40 - camelbak - 100oz. Over 40 - camelback, 2 bottles. Tour - over 1 day - camelbak, 6 bottles (4 in panniers - until I figure out a way to zip tie cages to racks.