BMX Race Frames Expert

BMX Race Frames Expert: frames in the Expert size class. Top tube approx. 19.25" to 19.75", for a rider height of approx. 4'7" to 5'1" (140 to 155 cm). These are guide values; every brand publishes its own chart, and at the boundary it comes down to preference: smaller is nimbler, larger is calmer on the straights.