NGG

All;

Would appreciate some advice.

Just picked up my new 07 IS350. Door jamb sticker states tire pressure should be 35 psi front and 37 psi rear. Sticker also makes reference to maximum load of occupants and cargo should not exceed 825 pounds. Here are my questions:

(1) Is the recommended psi of 37/37 designed to support the maximum load?

(2) If so, then should the psi not be reduced if the normal load is equivalent to the driver and occasional passenger which is substantially less than 825 pounds ?

(3) If as in #2, psi should be reduced, what should it be reduced to?

(4) What is the factory/default setting of the Tire Monitoring System (TMS). Is it 35/37 or something less?

(5) If it is less, what is it?

(6) Can the TMS settings be changed to reflect the lower pressures so the alarm is not activated until tire pressure is less than the new settings?

Gentlemen, I know that these are a lot of questions but would appreciate a response so I may balance tire wear with ride comfort. Thanks.

NGG

caymandive

iTrader: (2)

Pretty much stick to 37psi rear and 35psi front and you'll be fine. Don't over worry about it. As for what the low psi warning is I believe it's default is 29 or 30psi. I found this out because every time i hit the drag strip and lower my rear tires to 28psi I get the warning light. Seems to come on around 29/30psi rear. As far as being able to change the default settings I'm not really sure how to do it, but perhaps someone can fill you and I both in.

NGG

Thanks. This is very helpful as I am thinking of reducing the pressure by about 2-3 poundes to improve ride quality but did not want to trigger TMS sensor warnings. I am trying to balance performance/tire wear/ride quality. I am not a "boy racer" type. In fact I am 64, but still like the performance envelope! Thanks again.

NGG

C'mon guys. Help me out here. Would really appreciate some input to my earlier questions.

Irishman06

TPMS is calibrated to react to a change in pressure greater than 12psi/min, but it will also catch a slow leak if the tire pressure is more than 8psi below the "normal" value. They're calibrated during the Pre-Delivery Service, but I can't remember if you need a scan tool to set the TPMS ECU into "calibrate" mode.

NGG

Thanks for the input.

SParker1tx

So what exactly are the advantages to keeping them at 35/37 verses say 32/34?? Lower the pressure better the ride?? But higher the pressure better MPG? Not really sure...

clubfoot

Use the recommended pressures on the door jamb as Lexus has taken most of the guess work out of "what pressure" to use, for you,...so use 35/37 psi. It is the best compromise between, ride, handling, fuel economy, wear,... etc. And I say this because you have 18" wheels with a 40 series profile there is not allot of protection built in for pot holes and rough roads.
To re initialize the base setting, use the satellite switch to the left of the steering wheel, select MAIN, and hold the center button in until it beeps with the IGN ON, engine off.