I have the 17" chrome wheels on my 2002. Factory spec for the H-rated tires is 32 psi. I lose about 1psi a month on 3 of the 4 tires due to bead corrosion on the chrome wheels, so I keep all 4 tires at 33.5psi. A few pumps with my Lezyne Digital Drive every few weeks keeps the tires healthy.

I check the spare in the trunk twice a year (at the seasonal tire rotations) and ensure it stays at 33.5.

 

Like some said above, the dealers are keeping more than 40Psi. I checked my tires and I was surprised. Front tires were 41Psi & Back tyres were 32Psi. I made to 35psi all round and I feel like am in heavens, superb smooth drive...Thanks guys for your posts.

 

I have been experimenting with 30 to 37 and find the car responding much better at 37 all around. The ride quality is much better, perhaps due to the weight of the car

 

This is the tire that always gets forgotten about. I looked at the spare on my 01' when I brought it home last year, and it was almost flat. Maybe 9-10 PSI in it. So, it's a good reminder to check the spare at least twice a year, or in the fall and the spring.

 

hydrogen air is the way to go, it maintains the air in the tires for a very long time, also i noticed the car rides better.

 

Hydrogen will not make the car ride better. LOL... It will keep the PSI at a stable level during temperature swings.

 

I'd personally prefer Nitrogen over riding on 4 mini-Hindenburgs

 

I put Nitrogen in all the tyres with 35PSI all round and now its running very smooth.

 

Felt the ride was a little stiffer than usual on our 245/45R18s and found the pressure was at 36.5. Had recently taken the LS into Lexus to have some custom settings programmed. Service receipt shows they checked the tires and inflated to spec. However, the door label says it should be at 33 PSI. I used a digital gauge to lower it back to 33 and can feel the car rides smoother.