The 14-in size bridges the gap between a first 12-in bike and a 16-in, sized for riders 37.4 to 43.3 in tall with a 20.5 to 21 in inseam. It leaves the box 85 percent built with the tool needed to finish, so a birthday morning does not turn into a garage project. Two brakes cover the transition years: a hand lever at 29 to 30 in high and a rear coaster brake. Training wheels come off the day balance clicks, and a flip lever moves the saddle without a wrench.