The story of my (tankbag) life
My first tank bag was a Tour Master. It was mostly notable for being the least expensive tankbag I could get. My first vehicle was a 86 Ninja 600R, and the tankbag got a heck of a lot of use, mostly carrying my books for college. However, I didn't have any experience with tankbags, so I'd gotten a big one that hit the horn button on full left steering lock and the starter button on the right. It also had this horrible strap system that required disassembly of several major parts to install. This meant that you left the ugly straps there all the time. The bag had a neoprene bottom. Dirt and dust got in between all the time and scratched stuff up. I would rate this bag a 2 out of 5.
My next tankbag was the factory BMW tank bag for my second (and third) bikes, both an '86 K100RS. This was probably the best tank bag I ever owned, and it was included with the bike (bought used). It used a mounting system I haven't seen since. The bottom part of the bag was a leather mounting piece with three form-fitted legs that went to metal flat hooks. A hook grabbed the front of the tank and either side. Some sort of sheepskin-like material protected the tank from scratches. This bag, designed specifically for the bike, was narrow enough not to hit any buttons at full lock. When fully expanded though, it got tall enough to block vision of the dashboard. Also, it wasn't very rigid and flopped over. I would rate this bag a 3 out of 5.
My third and last tankbag was the factory BMW tank bag for my fourth bike, an '00 K1200RS. It rested on foam pieces glued to the bottom of the bag. That didn't last. Also, it attached with VELCRO for crying out loud. I had to stick a piece of velcro to the front of the tank. This failed three times in high wind situations, leaving the tank bag flopped off the side of the bike, hanging by the back straps. It was really stressful trying to the control the bike in the high wind; with the tankbag flopping around it was super stressful. Even in medium wind, the map pouch would fly up into the air, twisting endlessly around. One would think there must be no wind in Berlin. There was a bungee cord running around the perimeter of the bag. I could never figure out what it was for, but eventually used it to pin the map pouch down. This was probably the worst tank bag I ever owned, although it wasn't all bad. It was purpose-designed for the bike. Buttons didn't hit the bag at full lock. If the mounting system were better, I might give it a 3 or 4, but its complete inability to handle wind puts it at a 1.5 out of 5.
Having sold the KRS, I am now tankbagless. I've been so disappointed in them, yet they are so handy. I've thought a lot about what I want in a tankbag and I realize that I want a tankbag to act like the factory saddlebags: a strong mounting system that doesn't scratch the paint, lockable, and weatherproof.
Some tankbags have come a long way. The Big Mak, Marsee (with Corona mount) and SW-Motech all have touchless and strong mounting systems. Marsee has a couple of bags that are rigid, and, I'm guessing, weatherproof.
I guess my main complaint now is that they aren't very secure. Tankbags are, ironically, where people tend to keep a lot of valuables. Camera, phone, GPS, sunglasses, maybe even a wallet? And yet it's the one bag that isn't secure. Meanwhile, our locking luggage has some crappy t-shirts and dirty underwear. So you've still got to compromise with some sort of hassle: either risk leaving it out on the bike at every stop, or drag the damn thing with you into every restroom, gas station, restaurant, whatever.
Ideally, what I'd like is a large, locking storage area built into the tank itself. Raise the tank height by 2 or 3 inches and include a large 8x8 storage area. Inside is a cigarette lighter receptacle for charging the phone or whatever. The lid would have a light, illuminating the storage area. The release button would keyed to the ignition and could be left in a locked or unlocked state so I could use it without the key if I liked. The storage area would have a thin rubber lining to prevent stuff from sliding around and scratching.
I can dream, can't I?