So, my friend's kid's bicycle has an 18" tire that is completely worn down. I'm having a really tough time finding 18" tires on local buy/sell websites, but there are a bunch of 16" and 20". Does anybody know if putting a 20" (or 16") wheel on my friend's kid's bike will work? No gears, just back pedal braking, and a hand brake for the front wheel.
Thanks a lot.