To unlock the Pro bikes you have to beat the Pro Bosses. Each Pro Boss you beat will unlock a different Pro bike. You unlock the Pro bikes in the following order. * Pro Bike 6 - beat Super Shrimp * Pro Bike 5 - beat Up Chuck * Pro Bike 4 - beat Wonder Wind * Pro Bike 3 - beat Limitless Liz * Pro Bike 2 - bea...