On a side note - if someone is looking for more capacity (again, back to the math and adding up the capacity you may need) - you can do the 10L sacks in the front and another 20L, or even a 30L, as a top duffel in the back, or a 10L hanging from the handle bar. I suppose if you had a lot of bulky light weight items you could go 20L's on the front, having the extra capacity may be nice if you need it, you just don't want to load up the front too much. I would be curious how the 30L sacks would work out as the rears. They would be another inch or so in diameter and a few inches taller so they may work out fine too.