look at my transport system.
The photo was taken in summer 2004 above Val d'Isère in the French Alps. In the luggage bag are: luggage for 2 persons for 2 weeks (we stayed overnight in more or less cheap accommodations, see
here ), tool and food supply (13 kg). One can transport also a small camping equipment.
Advantages: One does not need further luggage bags, the handling characteristics of the bike remains. Climbing and driving downhill are problem-free.