1. Top tube
The length of the top tube is what all BMX frames are measured by. As well as offering more room for the rider if it is longer; a longer top tube will also make the bike more stable. A shorter top tube will make your bike more responsive or twitchy.
2. Chain Stay
Essentially the legth of the rear end. The shorter it is the more responsive your bike. Wheras a longer one is more stable.
3. Head tube angle
Determines the angle of which your forks point towards the ground and therefore how your bike turns. The steeper the it is the quicker you turn. (The greater the angle the steeper the fork angle is i.e. a 75 degree headtube is steeper than a 74 degree headtube).
4. Seat tube angle
This doesn't vary that much and is usually 71 degrees. It affects your center of gravity . The steeper it is the shorter your bike will feel or the more forward your center of gravity and vice versa.
Make this more significant:
