fourth pinion

例句：

1. 1. The car was fitted with a new fourth pinion to improve its performance.
   这辆车安装了一个新的第四根辐条来提高它的性能。
2. 2. The race car had a unique design that included a fourth pinion system.
   这款赛车具有独特的设计，包括一个第四根辐条系统。
3. 3.The engineers worked tirelessly to replace the old fourth pinion with a more efficient one.
   工程师们努力不懈地将旧的第四根辐条替换为更高效的一根。