Tires: Tire pressure, toyota highlander 2005, ford f 150

Question
QUESTION: What is the correct tire pressure for p23570r16 on a Toyota Highlander 2005 2wd? I have just purchased this car and the sticker inside the door has recommended tire pressure of 30 psi for P22570r16. The car came with the P23570r16 tires. Are these tires suitable for this vehicle?

Thank you.  


ANSWER: Mike,

I've verified all the info you gave me using Tire Guides - a publication that summarizes vehicle placards.

In order to carry the same load as a P225/70R16 does at 30 psi, a P235/70R16 needs to use 26 psi.

However, why not take advantage of the increased load carrying capacity by using 30 psi.  You'll get better fuel economy, better wear, with no loss of ride comfort.

BTW, your speedometer may be off a bit - about 2% low - so you'll be going faster than indicated.

---------- FOLLOW-UP ----------

QUESTION: That seems low. I bought the car yesterday and the tire pressure the Toyota dealership had in the tires was 36-39 psi. I have not checked with them yet. I noticed in your response for the same size tires for a Ford F-150 that you recommended the tire pressure should be 41 psi. The tire pressure warning system light is on. I thought that indicated too low psi. I am a little confused.

Thank you for your quick response to my original question.

Answer
Mike,

Too low?  Let me assure that the information I gave you is correct.

Secondly, my answer for the F-150 was for an F-150 and not a Toyota Highlander.  Check my other answers and see if I don't employ the same methodology on all of them.

Ah, the tire pressure warning light.  These are generally set up one of two ways:

1)  Diameter differences:  These detect differences in rolling circumferences and then set off the alarm.  But if the tires are equally low, it won't set the alarm off at all!

2)  Actual pressure:  These will detect low pressure compared to the original pressure setting as indicated on the placard.  Needless to say, it doesn't know that a different tire size has been applied.  It only knows what pressure it is seeing.

But some systems have to be reset after a tire change - or may give you an error reading if the pressure devices are broken.

I don't know which Toyota used in this case.  Perhaps logging into a Highlander web site might be of assistance in this area.