I think I’ve found the ideal mountain bike pack, the Deuter Race X Air 1. Over the first few rides I’ve really noticed the advantages of the Aircomfort back system. It really keeps your back cool while still keeping the pack from moving around while you ride. 850 cubic inches is plenty for the essentials for any bike ride. I always carry a pump, extra tube, patch kit, tire levers, multi tool, a few Cliff Shot Blocks, and water. This pack carries all this and has room for an extra layer or more food for an epic ride. It doesnt have a ton of internal organization pockets, but the front pocket keeps your wallet, keys, and phone handy, and the side mesh pockets are the perfect size for an extra tube or energy bar. The Deuter Streamer resevoir that comes with this pack is the best I’ve used. The fact that the whole top opens makes cleaning it after a ride much easier than with other brands, just wipe it down with a paper towel and hang it upside down to dry. While I am primarily using this pack for biking, It would be a great small daypack for someone doing fast and light hiking as well.