So here is a data point for those considering the life of the 21 summer tires. Obviously, your mileage will vary, but this data point may help. My lifetime average is around 320 Wh/m if that helps you figure out my driving style. I got my P85D with 21" wheels and summer tires in August 2015. In early December I popped them off myself and swapped them out with a 19" winter package (Rials + Michelin X-Ice). I don't know what the starting tread depth was but I think most new tires come around 9/32" or thereabouts (please correct me below if I'm wrong). After 6000 miles between August - early December, here are the tire tread depths. I wrote down three readings per tire from the inside edge to the outside edge. For each reading, I sample three times in slightly different spots to average out the readings. Tire Setup: Michelin Pilot Sport Front: 245/35 ZR21 (96Y) Extra Load Rear: 265/35 ZR21 (101Y) Extra Load At 6000 miles, Dec 2015 Tread depths are from inside edge to outside edge. Driver Front: 8/8/8 Passenger Front: 8/8/8 Driver Rear: 7/7/7 Passenger Rear: 7/7/7 I don't really do any full on launches and I tend to cruise just above the speed limit. On highways with 65mph, I'd typically do around 70 and let everyone else go around me. I would say that the tires are still good for another 6000 miles at least and I was expecting/budgeting for around 12,000 miles. That's pretty much what low profile, high performance summer tires have gotten me on my Porsches. Clearly, this car is much, much, heavier, so maybe that wasn't a fair expectation. Nonetheless, so far I'm on track.