The decal on the inside door jam specifies that my tires (18" version) should be inflated to 30 psi. I went to the air pump at the gasoline station and checked my pressure (with both their built-in gauge, and my own personal gauge). The car had not been driven in 3+ hours, so I assume the tires were "cold" (the station is 1/4 mile away). Both gauges read all the tires at 32 psi. Seeing no abnormal wear in the middle of the treads, I opted to keep them at 32 psi.

My thoughts were if I deflated to the recomended 30, my mileage would be affected, albeit probably unnoticeable. In addition, I'm driving about 3-1/2 hours on the freeway tomorrow, so isn't a bit higher pressure good for (relatively) fast freeway driving?

Thoughts? Comments?


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I always keep my tire pressure 2 to 3 PSI higher than factory recommand to get better gas mileage. usually, I go back down to factory recommanded pressure in the winter time to get better snow traction, but I dont think you guys get too many snow stroms out in Cali.

 

On regular driving, it is recommended at least 1 psi higher than posted PSI. If you can accept the harder ride, it actually saves your tire, saves you gas, too. When I come home, I will pump 32 on my tires. Also tries to ecen out the wear, look at your tires, they wear on on the edges all the time, sign of under inflation...(ok, there's camber and toe in issues as well...).

 

but I dont think you guys get too many snow stroms out in Cali. [/QUOTE]
Blue Canyon,Ca gets more snow on the average than any place in the U.S.

 

30 psi is just Lexus' recommendation to balance ride comfort, mpg, and tread wear. You should adjust to your preference with no additional safety risk as long as it is won't exceed max PSI cold.

 

Max PSI cold for the Goodyear (pso) RSA is 44 psi.

 

FWIW:
Even 1/4 mile will flex the sidewalls enough to generate slightly inaccurate pressures. And usually the air gauges on ends of hoses aren't very accurate. Have you checked your gauge with a master gauge, making sure yours is reading correctly??
My suggestion is to check pressures in the garage before driving to air pump.
Nitogen will control variation in pressures during operation and warm temps.(used in jetliner tires, NASCAR, etc). Even tho it's mostly H20, it's still more stable(pressure-wise) than regular air.
I replaced the air in my tires w/nitrogen in my 330. Just as in my Honda. The pressure variance is negligable in all ambient temps.
I operate the 330(80% city) with 34psi.
Good Luck.

 

I pumped up mine to 32 last night. Maybe I need to get it up to 34.

 

What imporvement are you looking for:

Tire wear, ride_comfort, braking, fuel_economy, handling (dry, wet, ice, snow).

At the end it is a matter of compromise. Hopefully Lexus ran all possible tests/scenarios to come up with the suggested psi.

Salim

 

Mainly tire wear and fuel economy. A harder ride is actually preferred. Since we have decent roads in Atlanta...not much pot holes, etc...

 

Go with +5psi on decal. [Just an approximation but keep an eye out for faster wear in the middle].

That said, it will reduce your braking capability and wet traction along with stearing ability.

You already mentioned the ride comfort ... but keep in mind that passengers are sitting on a cushioned seat. The constant jarring does reduce life of rest of the components.

Nothing comes for free

Salim

 

Great, I will be at 34 psi....

 

Been running at 34 PSI since I changed to Michelins (from crappy Goodyears) and have had no issues, including driving in blizzard conditions on our mountain passes. I did not note any adverse reaction to stopping distances, nor to wet traction, and living in the Pacific NW, we know all about wet traction!

 

34 seems to be a good psi to stay in. Thanks.