This might be better for my diehard biking buddy. We test drove the smallish model, and he was having a hell of a time trying to use it while we were biking behind him and shrieking with laughter. His feet were so big that his foot was either hitting the rack on the back, or the front wheel whenever he was pedaling.

This resulted in him limping around three blocks with a dorky demo vest on, while we shouted suggestions and he indignantly tried to find a body position that allowed him to ride xD