I'm 6'2" and I've tried using my Gregory backpack with the hip belt removed but found that at 5500 cu/in it's just too much bag. On top of that the shoulder straps are wider to spread the load. On the bike it's kind of like shrugging your shoulders and all of the padding is definitely noticeable and eventually annoying. Having said that I think a hiking pack somewhat smaller, with a removable hip belt (or cinch it tight and clip it backwards around the bag), maybe designed with some climbing in mind might work. I like hiking bags because they always seem more sturdy, and simply built.