I had meant to lock it to something sturdy in the garage. Maybe hide it, or keep it inside like the valuable thing that it is. I had put my clipless pedals on it so I did not think anyone else would use it. Using some brilliant deduction, I soon confirmed that my 18 yr old son had borrowed it, riding it with tennis shoes! Needless to say, he received 2 lectures upon his return: no riding dad's bike (without asking), and don't ride clipless pedals without cleats!