一、挑选自行车时应注意以下几点1.自行车各紧固的螺钉螺母应是旋紧的,不得松动和脱落。2.各转动部件应运转灵活,不得有卡住、僵呆现象。3.变速车在变速范围内应变档正确,变速位置应清晰,中间不得有空档。4.链条应松紧适宜,运转灵活。用手正向、逆向反复摇动曲柄链轮,链条运转 First, the selection of bicycles should pay attention to the following points 1. Bicycles each fastening screws and nuts should be tightened, not loose and fall off. 2. The rotating parts should be flexible operation, there may be stuck, stiff phenomenon. 3 speed change gear in the gear shift range should be correct file, variable speed position should be clear, the middle may not have free gear. 4. Chain should be tight fit, flexible operation. Hand forward, reverse repeatedly crank crank sprocket, chain operation