I coldn't ride with my tank bag. On this cold wintery day I checked my tank bag and here is what I found:
Registration, Proof of Insurance, Owners Manual, Sun glasses, Reading glasses, Copy of Rider Assistance list, AMA card, Cable and lock for helmet and suit, Side stand pad, Cord for electric vest, Cord for GPS, Cord for cell phone, Flashlight, Bic lighter, Sun screen, Chap stick, GPS, GPS cradle, Cell phone cradle, Bandana, Ear plugs, Cork screw for wine bottles, Piece of rope, Notebook and pencil, Lens cleaning fluid and wipes, Duct tape, Zip ties, About 6 maps, Change for parking meters, And about 100 gas receipts.
And when I go on a trip I stuff even more things in there (somewhere). Don't even ask what is all the pockets of my "Stich".
I don't have a top case and I don't miss the weight of one either.