Where is any authoritative evidence that **given the same tires** the 21" wheels are significantly higher performing than the 19" wheels? Are there any direct comparisons using the same tire but different wheels at the drag strip, skidpad, track, or an efficiency/range/rolling resistance comparison? It seems to me that there is substantial anecdotal evidence in these forums that 21" wheels perform much worse than the 19" wheels when going over potholes and when trying to maximize battery range. Where is the countervailing evidence that they perform significant better in either acceleration or handling or other areas? Note, this is not a question about the tires, but simply wheel size. Also, armchair theorizing and speculation isn't very useful -- any real evidence? Does anyone have any evidence to support their position that 21" wheels are substantially better performing than 19" wheels with the same tire? Since there is significant evidence that tires vary widely in performance, but none that 21" is better than 19", it is likely that: -- the tire choice on either wheel is what primarily determines performance (handling, skidpad, acceleration). -- the wheel choice likely only affects aesthetics, pothole resilience and ride harshness.