2 speed driving axle,has lower speed to get large torque on mountain road and normal speed on flat road,bridge---shell style Rear axle StyleFull floating,Half ... :Max engine speed 8500RPM,Max powe 10KW,sub-axle speed 2180RPM,wheel radius 235mm RatioMax Speedfitful road 9/3539.7KM/Hourcountry 8/2744.1KM 250cc gasoline engine 2 speed tricycle rear axle