The sudden success of Pihsiang's four-wheeled mobility scooter stemmed from a chance event: at that time, due to a spinal swelling, Wu himself was driving around on a three-wheeled scooter he had modified himself, and the scooter fell over. He came up with the idea of a four-wheeled scooter as a means of improving driving stability.
至於讓必翔一炮而紅的「四輪電動代步車」，起因於一個偶然，當時伍必翔因脊椎長瘤經常開著自己改裝的三輪電動車代步，有回不慎翻車，為了提高行駛的穩定度，於是興起研發四輪電動車的念頭。