Originally Posted by noglider

Don't forget size of the rider. It gets complicated, doesn't it. Suppose we decide that people over 6'2" (188 cm) tall really need to be riding 30" wheels. Should we make a new standard for them? Should adults buy bikes sized not just in frame sizes but wheel sizes? I hope not. It's bad enough that there are 12", 16", 20", and 24" wheels for kids.

And have you ever noticed how bad most 24"-wheeled kids bikes are? I'd try to keep a kid on a 20" bike as long as possible until she's ready for 26".