The geometry is what makes a bike ride like it does. It's the main thing to consider when choosing a frame. It's actually pretty simple. There's: *Wheelbase- the measurement from the centre of the rear wheel axle to the centre of the front axle. Short frames are generally considered better for natural, long for street. *Bottom Bracket rise- imagine a line going from one wheel axle to the other, BB rise is the height of the centre of the BB shell above that imaginary line. Higher bb feels better on the back wheel and improves balance. Lower BB is better for 2 wheel balance and good for static moves. *Chainstay Length- centre of rear wheel axle to centre of BB shell. Longer is better for static moves but is normally worse on the rear wheel. Shorter is better on the rear wheel and makes the bike feel "flicky". *Head angle- the angle that your headtube creates with the floor, NO idea how that affects anything. ahaah that's my view on it anyway.