Tire Pressure
 

GS350 manual states for 18"Summer tires, the tire pressure should be 33
psi.
The door panel states the tire pressure should be 33 psi.
The Lexus service dept insists on 36 psi because "it causes less TPMS false readings". They will not lower the pressure and reset the TPMS.

I know I can do it but my question is 'Are they correct?' I thought the indicator light goes on when the tire pressure on any one tire falls below 4 psi of the initialized pressure reading. If that is the case, then it would turn on at 32 psi (36-4=32). If the true tire pressure should be 33 psi (as stated above), then that only allows a 1 psi lowering from the default of 33psi.

Shouldn't the tire pressure be what the manual and the door panel say it should be (33psi)????

Thanks for any help!

we keep ours overinflated by 2-3 psi. we got a nail one time w/ slow leak and it wasn't until 28-29 psi that the light came on.

sounds fine to me. i don't think it's reset to 36 initial tire reading. sounds like what they are saying is that putting it at 36 allows you 7-8 psi before the light comes on.

33 and 32 is so close, any of the measurement or equipment error will bring you that already

in any case, 33psi should be measured COLD, meaning when it's in your garage first thing in the morning before you drive off. a lot of times when cars are being serviced at dealerships, the tires are not cold anymore, that's why they put in a bit more

same with me, with my 20s i use 40psi "cold" as the golden number, but by the time i arrive at the gas station, i usually put in around 43 to 44psi, give it 10%

So then 36 PSI would be a safe number after a drive to the gas station?

well, technically it depends on how warm your tires got already, etc... so it's hard to give a hard number

another way i do it is before i leave home in the morning, i measure the pressure in the garage. say i want 40psi, but in the morning i see 38psi. that means i need around 2psi.

so i drive to gas station and then measure there. maybe i see 42. so i will do it to 44. and if i have driven the car for long before i come to the gas station, maybe i see 45, then i put in 47

again, just my 2 cents and how i do it