Submitted by Volker.Berlin on March 21, 2012
A few times the question came up which tires would come standard with the Model S. The answer is now up on the Specs page:
"19" cast aluminum wheels with all-season tires (Goodyear Eagle RS-A2 245/45R19). Note: optional 21" wheels come with Continental Extreme Contact DW 245/35R21 tires"
To me this seems to imply that there is no difference between front and rear, i.e., it should be possible to swap tires to increase their life span. The rear tires will probably wear significantly faster not only because the rear wheels are the driven wheels, but also because regenerative braking can (for the same reason) only be applied to the rear wheels.