Step 1: You will need a BMX front wheel and a caster wheel
As shown in Figure 1, you will require a pair of wheels - a standard front 20 inch BMX wheel and some kind of caster wheel like the ones you would find on the front of a shopping cart. The larger the caster, the more fine control you will have over the scooter, so choose the larger diameter caster wheel you can find. Also, rubber or air filled caster wheels are better than hard plastic casters for this project. The caster wheel shown in Figure 1 has a diameter of 8 inches and was taken from an old wheelchair.