自由飞轮

例句：

1. 1. The car was so heavy that it couldn't be driven without freewheeling.
   这辆车太重了，无法不自由地转动。
2. 2.The bike has a freewheel feature that allows you to coast downhill.
   这辆自行车有一个自由轮功能，可以让你在下山时轻松骑行。
3. 3. The old bicycle had a freewheel that made it easy to ride over rough terrain.
   旧自行车有一个自由轮，使得在崎岖地形上骑行变得容易。