During the run-in (also known as break-in, run-in) period of a new car, some people say that it should not be driven too fast, while others say that it should not drive at a fixed speed. Some people even think that with the current manufacturing technology, new cars no longer need to run in. Is that right? As for the more and more popular electric vehicles, do you still need to run in without an engine? This episode of Longsir will help you clear up the confusion. In addition to telling you the importance and operation method of run in, it also deeply analyzes the occurrence of mechanical parts before and after run in. subtle changes. In the question-and-answer session, Lung Sir selected a few questions that readers are most interested in, and you must read them to the end.