Anyone here who has experience with a cycling tour of multiple days? If yes, how did you take your DSLR gear with you? In a backpack or in a bag which is attached to your bycicle?
I'm a bit concerned if a photobackpack is comfortable enough or a bicycle bag is save enough for the gear due to roadconditions expecialy on bad roads like gravel, dust etc.
Anyone?
if you are travelling self-supported with panniers and such, then taking a DSLR with you is feasible, though not particularly comfortable. Because of the extreme vibration that anything hard-mounted to the bicycle frame is subject to, I always carry my camera on my body to isolate it from road shocks. So your desire to use a body pack is sensible.
Given that you should keep as much weight as possible off your shoulders and back for efficient cycling, and that often cyclists will use shoulder-strap type hydration packs, the optimal way to carry any camera is in a waist pack. Up to a 3-lens setup can be carried in this way (though you won't appreciate the weight), and if you have a shoulder strap you can hook it in while off your bike to make an excellent hybrid carry system that is easy to work from; swing the back to the back and tighten the belt for long carries, loosen the belt and swing the bag to the front on the shoulder strap to work. Consider these packs if you have a small-to-medum body + 1-2 extra lenses - they all offer hybrid carry:
ThinkTankPhoto ChangeUp, WiredUp10, Speed Demon 2; LowePro Inverse series; Tamrac Adventure series.
I would personally stay away from photobackpacks (like for example the ClickElite probody sport, LowePro Fastpack, etc. other than the DSLR Video Fastpack), because they are not designed to give you proper ventilation and load distribution in the hunched-over position assumed by all cyclists (though mountain bikers have some advantage over road cyclists in this regard, but not really all that much). These bags work well for walking and hiking. I have found that the trampoline-style internal frame backpacks (always with a waistbelt - do NOT forget this!) made by Deuter and some other manufacturers work acceptably well for cycling as the frame has a large standoff from your back and a strong curvature that fits the cycling position better. However, these companies don't make photo-specific backpacks, so you will have to fuss with something non optimal.
Bottom line, though, I think that DSLRs, unless the small body type with small lenses, are really too big for cycling. You are carrying a minimum of 4-7 lbs. around your waist for a body, 2 lenses, and bag, which is a lot. If you are not pursuing the absolute maximum in image quality, a u4/3 kit or, even better, a Nikon J1 or V1, are much more convenient to carry and give excellent results. Many photographing cyclists, like myself, carry nothing much more than an enthusiast compact like a Canon S90/S100, Oly XZ-1, Panasonic LX-5, Nikon P7100, or similar simple, rugged, RAW shooting cameras. Unless you are on a trip with a specific mission to shoot top quality photos while getting there via bike, any one of these DSLR alternatives will probably be as satisfying to you and would be far more convenient to use.