Someone mentioned that the tires that the running preproduction of the Model S is rolling on Advan Sport tires. After some research here's what I found.
255/30ZR21
Load Index 93 = 1433lbs (650kg) per tire
Speed Rating “Y” = 186mph (300kph) 93Y RF Treadwear: 180
Traction: AA
Temperature: A180 AA A 1433 lbs.
50 psi
10/32"
28 lbs. 8.5-9.5"
9"
10.2"
9.2"
27.2"
765
Country of Origin "JP" = JAPANJP
255/35ZR21
Load Index 98 = 1653lbs (750kg) per tire
Speed Rating “(Y)” = 186+mph (300kph) (98Y) RF Treadwear: 180
Traction: AA
Temperature: A180 AA A 1653 lbs.
50 psi
10/32"
29 lbs. 8.5-10"
9"
10.2"
9.2"
28.2"
737
Country of Origin "JP" = JAPANJP
295/25ZR21
Load Index 96 = 1565lbs (710kg) per tire
Speed Rating “Y” = 186mph (300kph) 96Y RF Treadwear: 180
Traction: AA
Temperature: A180 AA A 1565 lbs.
50 psi
10/32"
30 lbs. 10-11"
10"
11.6"
10.9"
26.9"
772
Country of Origin "JP" = JAPANJP
295/35R21
Load Index 107 = 2149lbs (975kg) per tire
Speed Rating “Y” = 186mph (300kph) 107Y XL N0 (Porsche) Treadwear: 280
Traction: AA
Temperature: A280 AA A 2149 lbs.
50 psi
11/32"
33 lbs. 10-11.5"
10.5"
11.7"
10.6"
29"
717
Country of Origin "JP" = JAPANJP
Preproduction Tesla Model S tire information