I bought a 2013 P85+ CPO last year. It arrived with the staggered 21" wheels. I soon needed to purchase tires and decided to switch to 19" wheels. At that time, Tesla did not offer a wheel that looked similar to the dark gray cyclones I had on the 21"s so I went with TSportline for aftermarket 19"s that looked like the 21"s. I put Continental ExtremeContact DWS 06 on the TSportline 19s and I've been happy with the driving experience. During a long road trip, I noticed that my actual mileage was always more than the estimated. I then noticed that my displayed speed on the instrument panel was always higher than the radar speed when I passed one of the passive radar signs. When I took the car in for annual service, I mentioned it and wondered if the car was still set to 21" wheels instead of 19", which would account for the difference. The service dept said that it was still configured as 21", even though I had switched the settings in the controls, and they made the change. However, I noticed the same situation over the next 10,000 miles. Today I took it in for service and mentioned the same situation. The service adviser just called and informed me that my wheel and tire combination has a smaller diameter than any Tesla config. Based on my mileage and speed measurements, it's off by about 4%. TSportline has their specs on the website, and they match Tesla's specs, though slightly lighter. If that is the case, then the difference is either in the tires or I have a slightly out of spec set of wheels. I'm wondering if anyone else has encountered this and if they have any additional information to add. It's not a major issue, but it is a bit annoying to be adding extra phantom miles to the odometer and burning through warranty miles faster. I've put about 33,000 displayed miles on the car with this wheel + tire combination, so about 31,700 actual miles. I plan to try the Primacy tires next and see how that goes.