A number of people around here recommend loading 60 per cent of the weight on the front and 40 per cent on the back. I'd like to understand the reasoning for this. My setup has at least 75 per cent in the rear with just a handlebar bag, my tent and some water in front.

I've seen all sorts of rigs on the road but the majority have most or all of the gear in the rear. I haven't yet seen any with the bulk of the weight in front.