hello everyone.. i need your help..
i have an 08 C2 Coupe, and i filled up my front tires with 37psi, and my rears with 44psi, and for some reason as i am driving all of my tires except for the rear passenger side increase. for some reason that tire the pressure went down about 4psi, i dont feel any nuts or bolts, and i have been checking for a slow leak, and it seems to hold steady..

can it be the TPM? anyone have a similiar experience? i am nervous about bringing it in to a tire shop? i dont want them to damage the rims? in the same respect i have tire and rim insurance.. was just curious as to what you would suggest?

 

Is the core of the stem tight?

 

Damon thanks for the reply.. forgive my ignorance.. what is the core of the stem? the cover for the valve that screws on? that is very tight.. not sure as to what the core of the stem is?

please advise!

 

Did you check your pressures against TPMS with a handheld tire pressure gauge?

Also 37/44 is WAY too much pressure unless you are carrying 4 people and full luggage.

33/39 is the stated pressure in the manual for 2 people and luggage

 

thank you very much i followed what was in the door jam

 

Every valve stem has an outer that the cap screws onto, those threads are easy to see when the cap is off. The core of the stem also screws into the center of the stem as well and that's where the seal is created. If the core isn't tight the stem will leak air under pressure.

 

Get the porsche valve stem caps.

That higher pressure will wear your tires out really fast and cause noise from irregular wear patterns.

 

yeah that TP sounds high. And would also make the car ride roughly...

 

And like you, my dealer just inflates to the jamb pressure plate values for 4 passengers with bags.. despite me telling them I only drive the car with me in it and no bags. I had to tell them to set the pressure right.

 

Yeah. There's a warning on the doors that say do not use max pressure unless the car is loaded.

 

thank you folks.. i am going downstairs to adjust it right now..
Steven

 

Hold on Steven - if your car has 18" wheels 36-7/44 is the correct pressure. Most people on the forum seem to have 19's or more and they run lower pressures. Relevant page from the owners manual attached.

I run mine at 37/44 with no problem.

 

actually i have the 19" porsche turbo rims...

Steven

 

OK - nice!!

 

I have the same issue with my TPMS and have given up worrying about it. I go strictly by my tire pressure gauge when the tires are cold. TPMS is designed to warn you of extremely low tire pressures and not necessarily as a replacement for a tire gauge. I have had several cars with similar systems and frankly none of them were very accurate but all would warn of pressure readings well below normal and indicate which tire was in need of attention.