So, when a mommy speedo and a daddy speedo love each other... Okay, no...but I'm curious if anyone knows how the speedo readout is derived? Is it similar to most cars where its just based off the output of an rpm sensor? Or is there any GPS (or other magical) correction? Context is with respect to non-standard tire sizes, though having clever correction for stock size pertubations like actual manufactured tire size, tread wear, and tire pressure effects seems achievable...no...? On the other hand, stock tire sizes are in the noise between 19 and 21 (and 245/40/20) so perhaps tesla, like other manufacturers, doesn't really care about accommodating non-standard sizes?