My dealer inflated my Dunlop At20's to 55 psi!

Lets not forget that all tire pressures increase significantly as they heat up.

 

I can't believe this thread is three pages long...

 

I can't believe people still think they should run the maximum inflation on the tire instead of the pressure specified by Toyota (obviously not with different size/load range tires). But, here we are.

 

That is correct and Boyle's law of physics explains this. About "significantly increase" is mostly subjective. As rule of thumb for 10 degree increase in ambient air temperature causes 1 PSI increase in tire pressure.

 

WOW! That temp goes up quickly then. Might explain why after checking my tires before going to the grocery store, they were 5 lbs higher when I returned. I would say that's " significant "
Please keep the physics coming.

 

Another fun thing to keep in mind is that atmospheric air pressure varies inversely with altitude. So for every 1000 feet of elevation gain the atmospheric pressure drops approximately 0.5 PSI, and your tires internal pressure will also increase by about that amount.

 

As a bookend to this thread, this past thursday I replaced all of the oe tires with Falken Wildpeak AT3W's. Look great! The ride is a tad less smooth but nothing significant. America's tire gave me a trade-in amount for the oe's.

 

What PSI did they set them to?

 

55......

 

just kidding. 35. I set down to 32 next morning when tires cold (or as cold as they can be in California).