Thanks for good suggestions. I thought about taking the camelbak and locking the camelback to the bike, but I'm afraid I'll accidentally leave something of value in it. I don't like to run with it on my back--I have enough trouble running as it is! I rode today with the cable wrapped loosely around my waist. It was OK for just riding the 3 miles to the park. This bike is a mountain bike, with a sloped top tube and small triangle, so the top tube won't work well. I might try just using a small bungee cord to attach it to the rack, as it naturally coils into a small circle. It's just a lightweight cable to fend off impulsive children; no one else would be interested in taking this bike! If the bungee doesn't work, then I think I'll use Mikki's handlebars idea.