19VFB19

Anyone know the valve stem hole dia's in 996 and 997 wheels?

996 (non tpms) dia is slightly smaller than 997 (tpms) dia.

If you put 996 rims on a 997, you lose tpms because the valve stem sizes are different and you cant use your existing tpm sensors.

Next question.... wondering if anyone reamed the 996 holes to suit 997 tpms valve stems?

I cant imagine the minor difference in dia. would have any adverse effects on balance or strength.

Or did you disengage your tpms ... I think the dealer has to do this.

OKB

all holes are the same on all wheels

19VFB19

But..... my tpms valve stems from my 997 wheels
Wouldnt fit the 996 non tpms wheels?
So I had to use the non tpms valve stems.

This must make sense to someone?
Maybe I should take another look at how the tpm sensors are installed in the 997 wheels but Im pretty sure they couldnt fit the 996 wheels because of the valve stem hole dia.

19VFB19

Let me rephrase my question.
Why cant I use my 997 tpms sensors in 996 wheels.
I thought it had something to do with the valve stem hole dia?

semicycler

TPMS valve stems often have an outer sleeve that goes over the top. Remove the outer sleeve and mount the sensor from below. Then reattach the sleeve from above. TPMS valve stems are supposed to be one time use too. Replacements are cheap though, about $5 each.

OEM ones look like this. Can you post a picture of your setup?

19VFB19

Now we're getting somewhere.
I'll check it when I get home later today and post a pic.
Thnks

19VFB19

Original 997 wheels with tpms sensors









Wheels (apparantly off a 996) that cannot accomodate tpms?




What are my options?

semicycler

The 997 wheels have the OEM sensors as shown above. The outer sleeve unscrews and the valve stem is removed by pushing it into the wheel. The TPMS sensor itself is attached to the bottom of the stem by a screw as shown in your 4th picture. Normally the valve stems are thrown out and replaced. But the sensor is reused (the orange part). Take one off to see how it is assembled and to test the 996 fitment. I suspect most of your questions will be answered once you remove the 997 TPMS stem from the 997 wheel.

The 996 wheel is a normal valve stem (non-TPMS style) that just happens to be chrome. Yes the cap is chrome too, but so is the stem. The stem should push into the wheel to remove just like the 997 version, but there is no outer shell to unscrew first. There is no orange sensor on the other side too. I can't tell in the photo if a tire is attached to the 996 wheel. If it's not, can you take a photo of the underside of the 996 stem?

Generally the TPMS sensor with their matching stems should fit on any wheel. In rare occasions its the sensor at the bottom of the stem that has an interference when mounted. When this happens it's with older wheels manufactured well before the TPMS system was invented. But you can still mount TPMS sensors in those wheels with metal bands that wrap around the core of the wheel. It's rare to see this setup though. Honestly I expect 996 wheels to be able to mount 997 style TPMS sensors.

So to answer your question directly - the 997 sensors should fit on the 996 wheels. If they don't you can either look to having the sensors attached to the inside of the wheels with metal bands while using normal rubber valve stems, or disable the TPMS system in your car.

Banding looks like this, but you shouldn't need to go do this:

19VFB19

Great. Thanks for the info Semicycler
The 996 wheels are mounted so I cant get a good look
Inside right now.
When I put the car away for the winter end of Oct I'll investigate further but I think I will have to disable TPMS as the wheel installer guys also suggested.