The Pilot's "advertised" volume is 800 cubic inches (13L) capacity. On the other hand, a Timbuk2 Small Classic Messenger bag's (which I also own) volume is 854 cubic inches (14L) capacity, according to their website.
Based on not-rocket-science packing, the Tom Bihn Pilot holds WAY more stuff than the Small Classic Messenger Bag by Timbuk2. How can that be? Any light-shedding wisdom will be much appreciated, as I am a bag volume-minded individual. After all, every cubic inch counts, right?