mwaull

Just got my set of 20" wheels and tires installed and just wondering what kind of tire pressure you all are running. I have been told anything from stock pressure all the way up to 42 psi. I am running toyo T1Rs in 235/30 and 275/30, which have a max psi of 50. My pressure right now is set to 40 psi in all four tires.

Also, if you are running more than stock psi, are you getting the "low tire" light? I am and i really want to know if i can somehow reconfigure the system so it thinks my aftermarket psi is the correct one (so there wont be a light that comes up anymore).

Thanks ahead of time guys . . . i tried searching for this but only got threads about trying to disable the TPMS sensors all together.

cancellino

I keep mine between 37 and 40 PSI, it's too hot in Vegas (IMO) to run them any higher and risk tire failure. I have had no problems with the TPMS.

caribmon71

I'm thinking that you should still continue to go by what the sticker on the door jamb says. It also depends on whether you want your car to over steer or to under steer.

These can be affected by tire pressure. Since our cars are configured to under steer (or push or plow), I assume that keeping a higher pressure in the front tires will make them stick better in turns (as opposed to drag racing) than the rears, if you were to keep a lower pressure (on the rears). I can only assume that this would tend to compensate somewhat for the understeer.

Then again, under steer is much safer for the typical driver to handle than over steer. That is why most - if not all - production vehicles are set up to under steer instead of over steering.

What I learned in motorcycle racing and from other members on other car forums is that low pressure tires are good for drag racing in a straight line. However, when turning, a well inflated tire will grip much better than an under inflated tire.

Ok, I'm ready for the downpour of corrections. If I'm incorrect, by all means, please correct me! As stated, this is only what I've heard from other members on different forums.

Cheers!

mwaull

ok thanks guys for the advice . . . im leaning towards maybe lowering it to 37-38 and hope the alert light goes off.

anyone else?

tt061880

i put 36psi in all 4

IRCRomeo

I'm running 40-42 PSI with the TPMS indicator set around 30 PSI.

mwaull

what do you mean by this? So do you have any alerts coming up? I just want to have no more "low tire" light or anything like that. Can you change your TPMS indicator setting?

osokuko

I have 06 IS350 with 18's but also have 07 GS350 on 20's and run 37-38 PSI.

Hartawan

iTrader: (1)

245/30 - 40psi
285/35 - 38psi

IRCRomeo

You can't adjust the warning level but the dealer can.

mwaull

is there a warning light coming on for you hartawan?

Hartawan

iTrader: (1)

Yes because my sensors are still in my old tires lol . I am so lazy to go to a tire shop.

mwaull

i bought new sensors though and have them in the new aftermarket setup . . . i guess the alert is going off because the psi is too high.

so can the dealer reset it to where it wont think its too high? or will i just have to live with this alert going off all the time?!?!?

josephdoc

Maybe or very possible. TPMS-Direct_Type by standard should follow 25% tolerance from it's preset valve. If the module is preset at 35psi, error indicator will not triggered if air loading is between 26.25 and 43.75 psi. You sould adjust your tire pressure to your comfortable level and still under the tire's max air hold.

A link about TPMS by NHTSA. It is not the same as it says in Toyota's document. See my next note.


Incorrect!
About our cars, by TIS document #PG001-07, on page 4, it states every time when re-initializing the TPMS system, the existing tire pressure is used as Standard Pressure in all Lex 04 & up.

By government standard, the TPMS module is preset at chip level by its original manufacturer (not vehicle manufacturer) and should not be made for adjustable (NHTSA's TPMS standard). By the same standard, the module should be in sealed package and not to be serviced even when the battery is consumed.

Edit, snapshot of that TIS doc.


------------------------------------------------
At this moment, there is a lot of fuzziness on TPMS standard, and even a certified TPMS tech is confused.

mwaull

ok . . . so all of this means that as long as i am running higher than the stock range psi, i CANNOT DO ANYTHING to take off the warning light? Im just gonna have to live with it?!