I have a 996, and I have a set of 997 wheels. How can I tell if the previous owner installed TPMS on the wheels? Are there any visual cues? Thanks!

 

Metal valve stems is one.

 

Yea, the stems and the TPMS system will throw up an error if there is no TPMS.

 

Since you have a 996 then you probably do not have TPMS.

Porsche only started making TPMS available with the 997 series. It was an additional cost option until MY07 when it became standard in the US market.

The give away (as stated above) is generally the silver valve caps and a solid metal valve stem. Without any sort of display provisions within your 996 you will never see any readout of any kind. If the TPMS senders within the valves are transmitting (provided there is still some battery life in them--they will transmit to no where.

 

FWIW, my Champion wheels have metal valve stems and caps, and don't have TPMS sensors installed. So in some cases the metal valve stem does not imply TPMS is installed in the wheels.
I'm not sure why it matters to the OP if your car doesn't have the TPMS system to read the sensors. You'll get your answer next time you replace the tires on the rims. If there are sensors you can remove them and sell them, or leave them there.

 

TPMS valve stems look different from the usual metal valve stems for custom wheels. Take a look at the link http://www.suncoastparts.com/product...=997S_wheelacc

Photo A is the generic rubber valve stem, B is the TPMS type and C is the turbo type. My TPMS on my 2006 Honda looks pretty much like the B. Since you have a 996, you probably do not have TPMS. I have an 2006 C4S, and it was not ordered with it. I am considering getting this system from CarTonics http://www.cartronics.com/Porsche.html For $199 this system provides both tire pressure AND temperature. Anyone have these units?

 

You're right - moot point for the OP - 996 doesn't have TPMS.

 

FWIW- Yes, an old thread, but no one ever answered the OP original question of wheel-hole-size.
I just bought a set of 997 Style 47 wheels, 8"x18" and 11"x18" for my 996. The hole diameter for the valve stem is .443" or "smaller" hole diameter of 2 common sizes. The "larger" hole diameter is .624". Folks with the hollow Turbo-Twists has an even smaller hole and a special valve stem to fit everything, typical P-engineering.

If not using TPMS as the 996 does not have it, use short 1.2" metal stems. The valve core or the stem (or both) need to be nickel plated to prevent corrosion (electrolysis) of the valve stem. In addition, short metal stems are recommended for higher speeds (over 130mph) and there are lighter racing valve stems available. Rubber stems may not hold up at higher speeds that also generate higher pressures or bend.

The 997 wheels are/were used, so many (3) have TPMS sensors on them. Since is inoperable, remove all of the TPMS sensors and replace with new short metal stems. There are a few after-market TPMS systems out there if you want to have TPMS info.

One company I found has High Pressure Chrome Valve Stem (130psi) made for the .453" hole. Other less cost ones have a different rubber ledge-washer to fir either small or large hole. I don't like the idea of "universality", prefer a correct tight fit.
https://tiresupplynetwork.com/produc...=7519528255535

Another RL-r has this simple one which appears to work w/o a lot of hassle. It fits in the cig-lighter. Cost is low, ~$38, Amazon. Since it is slightly smaller OD, he had to shim it to stay in cig-lighter. There are others out there, but at more cost or have to be inside the tire on wheel. Offhand, I suppose you could buy a generic cig-lighter thing and mount it behind one of the unused oval switches on horseshoe and make it a more flush fit for looks.

So now I know more than I ever wanted to know about putting new tires on "blank" (new/used, no tire) rims. Some tire places won't put tires on wheels without the car. Also, many will not sell/install tires on something that isn't in their "Fitment Database". TS if their Fitment Database is wrong or incomplete. In the case of a 996 C4S, a 295/35r18 is not listed, but IS listed for a 996 GT2 with the same wheel specs as C4S. Dunno how this will work out but should be/hope OK. I don't want to take tires off existing rims, leave it at 2 sets. I don't think I could get all 4 rims inside the 996 to have the car there, and certainly not when all the tires are mounted. All these legal hoops just drive folks nuts, and wonder why legal profession has such a bad rep. Whatever, OK, off my soapbox.

YMMV

 

Since the last repy to this therad was in 2024, maybe I won't be ridiculed for responding to an ancient thread! What I want to know is can you get a decent 'OEM-like" TPMS on our 996.2s?
I used to have a 2003 Corvette and it came with TPMS that you could query from the dashboard and see individual tire pressures. It would be great if a combination of PIWIS, hardware and hacker spirit could give us 996 owners this useful feature.
Thoughts (and prayers)?