My grandson has the kind of bike you pedal backwards to brake, and he goes riding with me on my days off. Yesterday, he asked me if we can convert his bike because we have looked everywhere and no one seems to have a gear-shifting bike for someone who is 8. The Problem is that he is having trouble keeping up with me and wearing out a lot earlier because of the hills. Are there bikes with 18" or less wheels that shift or is he still too small for that kind of riding? I am pretty sure that I can figure out how to mount the gears and get a small derailleur just to learn how to shift and I am pretty sure I can change his brake system to the handlebar levers, but not sure it would be so wise, if I could just get his parents, who are willing and more financially able, to replace the bike with one that is built to be a dirt bike and not a trick bike frame with attachments to help him go faster.
I am pretty sure it is possible and I may even be able to make it just like mine but not sure how cost effective it is if he can just buy one.
I am still learning what different bikes are called. But he is about 3ft tall and his bike is getting too small for him. His current bike has 12" wheels.