My car has been at the Rockville SC for the past few days having some routine matters addressed. Whenever I have the car at Rockville I ask them to check for bent rims. The results are often depressing. For example I hit a large pothole a few weeks ago with my new 20" rims and Rockville now tells me they're bent front and rear on the right side (both ran into the pothole). This follows 2 bent Tesla 21" wheels that I had fixed last summer. I've also seen posts regarding bent 19" wheels so it appears that smaller wheel size is not immunity. My conclusion? With a car this heavy the only way to avoid bent rims is keep the car off pulbic roads. In other words, inmpossible. Sure, the odds are lower with smaller diameter wheels, but smaller wheels are no guarantee. The symptoms are usuually clear -- unusual vibrations when driving at speed that one might associate with balance or alignment issues. After I hit the pot hole I noticed a change in the ride immiediately and knew it was bent wheels. Of course, bent wheels can be repaired (in many cases you don't need to buy new wheels, as Tesla advises, just have them repaired). But when it happens it's a real PIA, especially if you don't have spare wheels (fortunatley I do). I've concluded that bent rims is something I have to learn to live with and factor in to the annual maintenance costs of the Model S.