There are two different types of BMX race bike: the 20 inch (your everyday BMX bike with 20 inch wheels) and the 24 inch cruiser (a slightly bigger bike with 24 inch wheels). You don't need a top of ...
BMX racing bikes are simple and strong, with a single gear and usually just a rear brake. Standard BMXs have 20 inch wheels and there are micro and mini and junior sized bikes for younger riders.