BMX wheels are typically 20 inches in size and only the tyre width varies based on the intended rider's age. However, some children's versions may also have 16- or 18-inch wheels. Most are quite knobby in order to absorb the shock from stunts, jumps, and tricks.
The two main types of BMX wheels are mag wheels and spoked wheels. The former uses alloy or plastic materials, while the latter features metal. Maximise your cycling comfort with the proper wheels.