During a road ralley I reset the odometer in my 300E at 70 mph. My odometer was knocked out of position. Later I put it back in place but would not not stay put, it eventually kept jumping out. After several attempts to correct the problem I finally sent it out for repair. I was told by a mercedes expert to never reset in motion. I never perform a reset in motion and it has worked perfectly since the repair. However, I frequently reset the odometer on my ford truck, gm car, and honda motorcycle without issue.