A bicycle store should be able to sell one to you, or you can order one online. Single wheel 24 inch isn't hugely popular, so you might have to do a bit of searching.
yes. Typically you will see a 21 inch front tire and an 18 inch rear. The taller, skinnier, front tire is better for s
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.
Something missing from the question, try again.
the crf 150rb has a 19 inch front wheel and a 16 inch back wheel
All things being equal, a 24" wheel will be stronger sideways than a 26" wheel.
The size of a child's bike ranges from a 12 inch wheel size for ages 2-5 to a 24 inch wheel size for youth ages. Usually a child with a height of 28-38 inches will need a 12 inch wheel size while a child that is 48-60 inches tall will need a wheel size of 20-24 inches.
15psi
It depends on if it ie front or rear wheel drive or 3 wheel drive. If it is 4 wheel drive, it is not good and will cause problems. If it is either front or rear wheel drive keep the wheels the same on the drive wheels ie. front wheel drive, keep the 17 or 16 inch wheels on the front but make sure they are the same.
The bike that you should think of buying an active 9 year old is a 24-inch wheel bike.
MAYBE - , frame size has nothing to do with tire size. Style does, and if its a mountain bike, it will not work with a 27 (road racing) wheel and tire. Brakes will not fit.
No.
the overall frame size. not specific to wheel size, as most mtb wheels are 26 inch.