The old truth was that you should have 1-2" clearance between your crotch and the top tube, but current designs often use sloping top tubes whch messes up the old reference. There are plenty of sites that'll give you some guidelines, do a search for "bicycle fitting" and see what you'll come up with. Try a couple of the different methods and them pick a comparison from the middle of the group. The most crucial value is that when you're in the saddle you should be able to have your leg almost fully extended when the pedal is at its lowest position.
You should be at least 5 feet 4 inches tall to comfortably ride a 29-inch bike.
bike
when you sit on the bike, you should be able to touch the ground with your toes.
Snowboard because its better than a dirt bike.
About 4'8-5'1.
The bike should have following qualities * Good looking * Good Mileage * no shakes, vibration. * Im 6 feet tall and slim person, the bike should go with my body style * 125 0r 150cc currently my options are Hero Honda(CBZ Xtreme), Honda(Unicorn and Shine).
Depends on how much they owe on the bike and if the price of the bike includes pay off to their bank and you get the title. If there is a lean holder on the bike and after you buy it you don't get a title then no I would not buy the bike.
pleasure
The bike that you should buy for your nine year old son is that with a 20-inch wheel with suspension forks and adequate front suspension.
Only you can answer that. If you have the money to spend, go ahead.
U can buy one on Craigslist (used)
If you can sit on the bike and touch the floor with your feet, you are tall enough for the bike