While this is likely to work much of the time, it wouldn't take a particularly strange algorithm to break it. Consider an average rating that is just the arithmetic mean of your last 10 rides. Your rating going up would just mean your most recent rating was better than the rating 11 rides ago that it displaced. If you got a 2 11 rides ago and a 3 on your last ride, your average rating would go up despite getting a below-average rating.