I've been out of the bicycle world for some time, still hanging onto my 1997 or so Haro Mountain bike. I'm looking for a bike for my son, 7 years old, fairly tall for his age. Prerequisites are NO coaster brake 20" bike, with either single gear or capability of locking him into a gear. He's not ready for shifting yet, just learned to ride without training wheels. Quick searching looks like the Haro ZX20 fits the bill, just don't want to break the bank. So, any bike guys on here have any recommendations? Thanks in advance.