Many EV owners experiment with tire pressure, looking for better range. The following research paper is fairly dry reading, but spells out the complexity of this topic, and draws some conclusions such as the following, referring to Cr, the coefficient of rolling resistance: "In Fig. 9 the results of road and laboratory measurements are compared. For both methods an increase in inflation pressure leads to a decrease in the Cr and the sensitivity slope is very much dependent on the level of absolute values of Cr. Tyres that have very low rolling resistance (that is tyres for electric vehicles) are rather insensitive to inflation pressure changes, while tyres having high rolling resistance are very sensitive." http://www.rosanne-project.eu/ajax/DownloadHandlerFM.php/downloadFile?id=11824
There's no harm in going substantially over sidewall pressure, and it brings other benefits like better handling/cornering and damage resistance over rough stuff. Modern car tires generally have a burst pressure around 300 psi. Mine went up to 60 psi the day I got the car home, just like I've run on the Prius for years. Rolls like a bicycle. _H*