Hi folks,

Couple of quick questions for those wheel experts out there. I have the opportunity to buy a set of 18" Cayman S standard wheels (take-offs) for a decent price to use as track wheels. I did a whole bunch of searching, but am coming up dry. Here are my questions:

1. Is there any way to tell if the wheels really are take offs (OEMs and not knock-offs)? I have high res photos of all 4 (inside and out) and I compared them to some of the photos posted in the wheel wax article, but is there any way to be sure?

2. Is there any way to visually inspect the wheel to confirm if it has TPMS or not? Is the stem different on wheels without it?

3. The wheels come with PS2's installed. I want to ensure they are not patched/plugged so that I can use them on the track. I plan to take them to my local shop, which also happens to be an installed for Tire Rack, to have them taken apart, inspected, remounted and balanced before I track them. Will this be sufficient to ensure the wheels are true?

4. Can I switch between 19" Carrera S wheels and 18" Cayman S wheels with the same length wheel lugs or are they different and would they require spacers?

Thanks in advance for help with any of the above!

pf

1 - Here's the PNs for 18" Boxster S wheels:
Front: 8 J x 18 H2, RO 57
Part No. 987.362.136.01
Rear: 9 J x 18 H2, RO 43
Part No. 987.362.138.01

2 - TPMS stems are silver and the difference in appearance from standard stems to TPMS stems should be obvious.

3 - Should be. If you do that, you should be able to check runout with a dial indicator.

4 - Don't know, but the difference in lug length is normally associated with the use of spacers.

OEM wheels are usually made for Porsche in Germany by either BBS or Rial... look for the name of the manufacturer - it should be stamped on (or molded into) the wheel, usually on the back of one of the spokes. My 19" sport designs for instance, are made by Rial. Most "replicas" are made in Italy.

The TPMS stems are metal and sort of short and stubby - non-TPMS usually have rubber stems

Make sure they have a good "road-force" balancing system (usually a Hunter 9500). Have them put just the wheels on the machine first to test the wheels for being true. With good road-force balancing you should be fine.

They should be interchangeable with he same bolts.

brad

__________________
21-year PCA Member
PCA DE Instructor

You can tell if it's a Porsche wheel by a part number stamped into the inside center of the wheel. It'll look something like:98736213601 (that's a front stock Cayman 18" wheel).

TPMS will be an obvious thing. I don't know what Porsche does, but some sensor/transmitters are strapped to the rim, some are an appendage on the valve.

Any tire shop can test for wheel run-out.

I don't know if the wheel bolts are the same.

Wow. I got beat in 5 minutes by two!

Great, thanks for the quick replies JackTs2K, beez and blueone!