Originally Posted by
10 Wheels
I had some cheap Nashbar bottles come out.
Regular size 24 oz and Polar bottles have stayed in even with the rubber band gone.

And you have your cages mounted on the hanger as high up as they will go.
There should be another set of holes in the cages that will allow you to lower the cages on the hanger about an 1" or so. That might be the difference - my cages have always been in the lower position and I've never lost a bottle.