Extra hole in wheel?

[innerloop]

Can anyone educate me as to the purpose of what appears to be an extra valve stem hole in an OZ wheel from a 2002 IRL car? There is a normal valve stem hole towards the outer edge of the wheel, but then there is a second hole, 180 degrees around the wheel, but very close to the middle of the wheel centerline, drilled not tapped. Sorry I don't have a picture. Three of the four wheels I'm restoring for a display car have this hole plugged with a nut, bolt and gaskets, but the fourth one is missing and I don't know where to get another plug. Can anyone point me to a source for these plugs? I'm also curious what the original purpose was for the hole... pressure relief valve, pressure monitor? Thanks.

[BWC54]

Could be for nitrogen purge.

[iamuwere]

Or pressure bleeder if Indy ever used those.

[David Ferguson]

Could also be a mounting stud for a wireless pressure/temp sensor.

[R. Pare]

Wireless pressure sensor as David stated.

[JohnCummiskey]

Yes this hole is for the TPMS sensor. If your just using the wheels for a show car the any bolt with a o ring will do. If your in Houston Foyt would have the proper plug if not I have a bunch.

[innerloop]

Thanks, guys. The local race prep shop had everything needed. The freshly painted wheels look great and now I can roll the car around since all four tires have air.