Thirty-one to 32 front 34-36 rear at 70F seems good. Precision with these big tires doesn't seem critical.

 

Bump..

My front is at 36 and my tears are showing 45. Running summer 20" pirellis Full load but when I go into fill info it says my front is 0 but my rears are -1. If the ideal is 44 why does it say -1 and not +1?

 

Normal for TPMS, +/- 0-3 psi variance considered normal spec.

 

Okay great. Thanks!

 

This is how Porsche does it. The -1 means you are 1 lbs above what it should be and you should remove 1 lbs of pressure. It was confusing to me at first too. If your fill information said +1 it would mean add 1 lb of pressure.

 

That is not my understanding based on reading the manual. -1 means add 1 lb

http://www.porscheownersmanuals.com/.../Tire-pressure

 

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To add to my previous post.
I lowered my rears from 45 to 44 and it still says -1 or sometimes even -3. I went in to reset it to 20(S) so I got the message that it is determining my PSI and once it calibrated it said my front is 36 and my rear is 44.
Odd that the computer thinks that the ideal is 36 front 45 rear no? Am I looking at this correctly?

 

Worth noting that I had a screw in my front passenger and rear passenger tires that got patched. Tires hold air perfectly and show consistent from 36 and rear 44 but the fill info is what's bugging me. The front's show 0 but the rears rarely show 0. Due to miss calibration in the computer?

 

Any thoughts? Can patching a tire affect/change the settings in the TPMS?!?

 

I found that my psi increases about 2-3 when the tires are at running temp. I have the pressures set at 33 front and 36 rear when cold. Unless you are driving with 4 people in the car, you don't need to run the full load setting. Check your manual, it takes a bit of trial and error. It all depends on how rough or soft of a ride you like and how quickly you will need to replace your tires. As far as patching a tire, it should not matter to the TPS unless the patch has a leak. Personally, I never patch and just replace the tire but thats only because I purchased the wheel and tire insurance for the crappy roads here in NJ.