My low air in tire light went on today. I drove into a gas station to check the air. A gentleman that worked at the station offerred to check the air for me. I said manual says 33 psi in rear and 35 psi in front. He said "you have radial and they call for 40 psi all around. Always go by what the tire says not by what the car says What's written in the manual is for 2 ply tires not radials as you have." I don't doubt his word but would like to get some feedback from other Prius people. The tires did say 40 psi on them. Thanks all
You should run about 40/40lb on the Prius (cold pressure reading). It will give you the best mileage and tire wear, IMHO.
What's in the manual is the minimum. What's on the tire is the maximum. But no matter what pressure you choose, make sure there is a 2 PSI bias in front for proper handling. I've used 44 PSI front and 42 PSI rear for years with my Prius.
The sidewall reading is the MAXIMUM cold air pressure. Don't exceed it. I usually bump it up a few psi over the factory reading. On my Prius, I have it at 38/36 (was at 37/35 but overshot one day and decided to leave it there lol). On the Camry, it's 32/32 or 32/31. Recommended is 28/28 which I think it's a tad too low. Even at 32/32, the ride's fairly comfortable.
Your gas-station gentleman is misinformed. The Prius ships with radial tires: Toyota did not put incorrect tire info in the owner's manual. Otherwise, what those guys wrote. The owner's manual recommendation is a compromise between handling, comfort and fuel economy. I settled on 42/40 front/rear. (Remember that tire pressures should be measured "cold", which means that the car has not been driven more than a few miles in the previous hour.)
<_< There are MANY threads on tire pressures in these forums. Seems to boil down to a personal preference comparing fuel economy to quieter ride for lower pressures. The number on the side of the tire is the recommended maximum cold, the placard on your car is Toyota's recommendation. I have run mine at 40 psi front and 38 psi rear (the 2# differential is Prius recommended) and have been pleased with tire wear. On problem with checking at a service station, instructions say set the pressure "cold," that is, after only a short drive or preferably after sitting until the tires adjust to outside temperature. I invested in a 12v mini-compressor and a high quality analog tire gauge to maintain pressures, and when I have my car serviced at my Toyota Dealer, they comply with my specified pressures (some Dealers don't want to).
