An alternate to taking pedals off a bike is to try them out on a little scooter. My three year old daughter had training wheels on her little bike, with no indication that they weren't needed. She wanted to try the "big kids' scooter," so I decided to let her try and wipe out and come to her own conclusion that it wasn't a great idea. Don't you suppose the little bugger coasted down the driveway twice with perfect balance? I took the training wheels off her bike and she got on and took off right away. Her five year old brother had learned to ride on his own just a week earlier.