I have my Model S scheduled to show up in a few weeks, and one of the first things I'm planning to do is swap out the all-seasons for performance summers. I've been looking at my options, trying to pick something that has a good mixture of performance and efficiency. I might stay on the 19"s, or move to 20"s, but since manufacturers don't really rate rolling resistance, I thought it would be interesting to see what members with aftermarket tires are getting for average Wh/mi. Opinions from owners with stock tires are appreciated to help determine the typical variance, though I can probably get a pretty good idea what those are from old threads. Further, this obviously varies quite a bit by driving style. My goal would be to try to avoid something like the Bridgestone Potenza S04 Pole Position, which I'm told has extremely high rolling resistance, perhaps the highest in its class. Anyway, I thought it might be an interesting topic for a thread. Maybe I get get an embedded Wiki so people can edit directly. If there's something similar that already exists let me know: a search didn't turn up anything. I'll have this one canned. Some of the options worth considering are as follows, and I'll add any new ones that get posted. I'll be scouring old threads in an attempt to find more over the coming days. Probably would have been better to start this in the summer before weather was a factor, but general "this tire seems much worse" kind of conclusions may still be possible. Stock 19" sizing: Goodyear Eagle RS-A2 (stock)257 (Thanks to jerry33) ~300-350 (Thanks to yobigd20) 312 (Thanks to JohnQ) 321 (Thanks to Liz G)Michelin Primacy MXM4 (stock)260 (Thanks to jerry33)Continental ExtremeContact DW Hankook Ventus V12 Pirelli PZero Runflats - Not recommended340 (Thanks to jerry33)Bridgestone Turanza Serenity Plus - Requested by Al Sherman Aftermarket 20" sizings: Michelin Pilot Super Sports255/40 front, 285/35 rear: 280 highway, 350 city/mixed (Thanks to gbdesai) Stock 21" sizing: Continental ExtremeContact DW (stock)330 (Thanks to jerry33) Aftermarket 21" sizings: Hankook Ventus V12245/35 front, 285/30 rear: 250-270 city, 350 lifetime (Thanks to gimp_dad) Notes: TireRack Comparison - Bridgestone Potenza S-04 Pole Position, Dunlop Sport Maxx RT, Michelin Pilot Super Sport, Yokohama ADVAN Sport V105 http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=174 Result summary: S-04s have 2-3% fuel economy hit compared to the other tires in the test. The PSS was within 1% of efficiency the leader, the Dunlop, while far exceeding it in performance. Also, two errors in the headline that can't be fixed... sigh.