Thanks for adding this info. Back in the old days of Prius (2001), there were many discussions about tire adequacy. I suppose they arose because there were quite a few problems with the OEM tires, especially those labeled "CHA" on the sidewalls. Later Bridgestone Potenzas were labeled "JDH", and were much less trouble.

It was a pretty universal observation that tires inflated per Toyota's spec (35 psi front 33 rear) would wear rapidly at the edges, characteristic of underinflation. As those tires also had a max. cold inflation of 50 psi, many got better results with inflations like 42/40. The worst problems might develop with lesser tires (like 81 load rating) inflated low like Toyota says, and with a heavy load.

DAS