Any one use a 2 fish quick cage?
If so does it stay put without rotating or sliding down or up the down tube?
I've got one on my road fixie. It tended to slide on my tubing but it's small diameter steel. I put a short, left over piece of handlebar tape around the tube then strapped it on and it's solid as a rock. No slipping, no rotating, works great. You could probably use a variety of things like inner tube, double stick tape, etc. Larger diameter tubing would also probably work better. It's not as solid as a cage held on with bolts but you can't expect something strapped on to be THAT solid. Nonetheless, it holds a 20oz full bottle over rough roads just fine.