my worst ride on the back step was in 281 when relocated to 318, Neptune Ave was like a wash board I don't think I ever bounced that much in my life. Even in the tiller of our 1979 Seagrave.
While not a "back step", most interesting ride was on the side running board of a 1940's-ish spare sometime around June 1969.
Every bump and pothole and felt throughout the bones