Bike Seat Bag, Bicycle Saddle Bag Under Seat Cycling Seat Pack with Water Bottle Holder for Mountain Road Bikes Black

Frame-mount cages, on Down tube and seat tube, are best because they help keep the center of gravity low. Take two full size bottles. That said, there are ways to store water just about any place you want. Above top bar, under top bard, front of head tube, camelback, under saddle, etc.