If you wish to travel along tracks and such, then a large tank bag is a hindrance.
I myself eventually setled upon the Touratech tankbag and find it's a very good compromise. A friend has the same tankbag but with the side saddle bags attached to it.
I've travelled two up fully loaded, at, or on the GVM of the vehicle, on tracks that incorporated sand, wet claypans swampy paddocks and the like. The ability to go from lock to lock at in instant, is really appreciated in these conditions.
As an adjunct, if you are running the TKC 80 knobbie type tyre, then the steering is a bit heavy in sandy conditions and sometimes standing up is easier. When you have to stand up when fully loaded, a small footprint tankbag is really essential, I've found.
I run the 41 litre tank and a full tank bag, albeit in the low position and I find it has ample room for all manner of things including the BMW first aid kit an Australian army issue water bottle, tubeless puncture repair kit from Tyre Pliers, spare throttle cables and a clutch cable, 8" shifter, 4 assorted spanners, spare cable tiedowns, multigrips, small & large Pedersen Vice Grips, folding one piece Allan Key set, Tent Light, 1/2 a dozen snack bar types of dried food, hand cleaner in a tube, rags to clean hands, waterproof matches, small torch, pen, sunglasses in L/H pocket and rain cover in R/H pocket, smallish camera in rear accessory clip on pouch, which clips onto your belt when away from the bike. These are the things that I can recall offhand, I know that there is a fair bit more in the bag!
A Leatherman on the L/H front of my belt, running in a horizontal sheath, gives me pointy nosed pliars and doesn't restrict forward bending movements, in fact I never notice that I'm wearing it.
The map container is velcroed on and is removeable so that you can study it when sitting in shade somewhere or hand it to a mate on his bike so that he can work out which way is lost or correct. The map container easily and near perfectly holds, the spiral bound HEMA Motorcycle touring map of Australia.
It's sort of dustproof and to a point waterproof but not downpour proof, hence the waterproof cover, which is an accessory. The waterproof cover also has a clear window so that like 2 weeks ago in the Snowy Mountains in foggy conditions with light snow falling, I was the only one of us able to read my map at an intersection.
The waterproof cover and the rear removeable pocket, are accessories, and need to be ordered seperately if buying the bag.
In short I think after millions of kilometres around Australia and various overseas countries, I think that the Touratech tank bag for the 259 series of GS bike, is pretty much as near to perfect as you'll get.
But that's my opinion, eh?
Mick.
Top Tip: the side bags come equipped with metal hooks on the end of their lower straps. I've taken these off, bought a dog collar of the correct width and used the plastic push fit/squeeze open type connector to join the straps under the tank & behind the front shock. This seems to work very well, stopping the bags moving about (thereby reducing the risk of chafing) aqnd saves the danger of having metal hooks unexpectedly dangling around your steering gear! (I've got a 30 litre tank, but I've tried thsi tip with a standard tank & it works fine).
