tmhcars

I have seen some discussion about Lexus recommending 40 to 45 PSI while the recommended PSI inside the door states 32 PSI. I realize that if one drives at high speeds the pressure should be higher but should it be at 40 to 45 PSI for those normal days when one doesn't exceed 100 mph?

tfischer

When I mentioned to my dealer that my low pressure light had come on once or twice in the past year, he said that they now suggest to all owners to fill the tires to 40 psi.

I have had them at 40 for the past several months, during the hot summer, with no problems and no false low pressure lights. I cannot tell the difference in ride between 40 and the mid 30's, where they were before.

antigeek

I realized that I had my tires at 32psi when I couldn't hit the clover leafs at a good clip anymore. I'd also hear almost a "fwap" noise on some roads. 32psi is fine for the Lexus' target demo (smooth cars for older people), but not for me.

It could be that the characteristics of the run flats change over time, as I now have 10k miles on mine -- still going strong.
But I upped the pressure to 35psi, and it corners much better.

My tires say max. 40psi on them. I decided not to go to the max (nor would I try 45). I recommend them around this range.
You'll get a little more bump from the road, but that's to be expected. And by comparison, it's still much smoother than any sports car.

Then again, the SC430 isn't a sports car, but that's another thread.