I have read the other screwy experiences from ealier posts, but my question is a bit different.

My street tires (19 inch sport design wheel with Potenzas) are in a neat stack in the garage and have about 1,000 miles on them. I noticed a screw in one rear tire. Near the center in a thick part of the raised tread. I unscrewed it and no air is leaking, but the screw is nearly a half inch long. I am imagining that it ALMOST punctured the tire, and I have visions of a tiny weak spot bursting through. These will never be run on the track.

What would you do?

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2007 Speed Yellow Cayman GT 2.7 (retired)
2008 Guards Red Cayman GT 3.4
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Me, I'd not worry if there is no leakage.

You know, that's a tough call. I had a 1/4 inch screw stuck in the same spot on my PS2's a while back when I had about 2000 miles on the clock. After looking at a cross section of the tire that Santa Fe supplied me (thanks again, ) I felt that I was in good shape and I am still on the same tires several months later. I would say that you're right that you are just about through the tire at 1/2.

I'll offer you the same advice I got from Santa Fe. Drive around your neighborhood and get the tires up to temperature. Watch the TPMS and see if there is any indication of a leak. Make your call after you do that.

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The tires are off the car, for simple piece of mind, I'd get it patched. What could that possibly hurt?

Patching with a plug will take away the current speed rating and is disallowed by Porsche. There must be a hundred posts on that subject with the both sides of that argument aired but if the tire is currently not punctured I sure would leave it alone. Take a look at the cross section of a tire and see if you think a plug would work at speed on a road course with all those cross sections.
http://www.caymanclub.net/gallery/files/1/7/0/PS2.jpg

I'd circle the spot, put some soap water over it, and pump it up to 50 or so PSI and watch it for a while (even recheck it a day or 2 later). No leak --> no worry.

If it does leak, I'd get it patched and keep it as a spare tire for the future.

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Nearly all of the hole is in the outer tread, but the very tip looks like it had to poke into the layer beneath the tread. The question is whether there is now a weak enough spot to cause a problem.

Here are some reference pics. Not great, but they tell the tale. The screw was retrieved with the underside of the cap flush against the tire, so only the screwy pointy part penetrated. Good feedback from everyone. Thanks.

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2007 Speed Yellow Cayman GT 2.7 (retired)
2008 Guards Red Cayman GT 3.4
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Tough call, Dave - it's not so much the air leakage, but as you said, the strength and integrity of the tire at that spot... and a 1/2 inch screw is pretty deep into the tire, that's for sure...even though they'll never see the track (a good thing to be sure) if you plug and patch, SF is correct - for all practical purposes the tire loses it high-speed rating... if you don't drive aggressively on the street, it's probably not that big a deal, but if you're driving to Vegas, let's say, and want to run it up into triple digits out in the desert, I wouldn't do it myself with a plugged and patched tire...

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I normally wouldn't patch my tires either, but in this case, where it doesn't seem that it will get a lot of use, (and NO track use) I don't see an issue. Plus, with the speed rating, how often are you going to get up to over 120mph on city streets?

There is no option for my choice, which is to use very ugly words, for a very long period, at a very loud and noticeable sound level.

Because this is not likely to be cheap.
If you are lucky, your tires are close to new, so you can replace one tire.
If not, it is not just to replace one tire, because the dynamics of the tire and the grip is affected by thread wear and tire ageing.
At least one must consider replacing the tires on one axle.
Which is what you will do when faced with the cost of one of these tires.

But, why not just.. ignore it, if it still holds pressure..
Yes, for a tire to be used ON THE TRACK, I might do that.
For a tire used in traffic, and occasionally at speeds up to their speed rating on the Autobahn, this is just not an option.
It might hold, actually I think it is very likely that it will hold, BUT the potential consequences are far too devastating if it fails.
Almost like the discussion in climbing societies, whether to leave one extra $10 sling to save your life when doing a roped descent.

(Driving around in the neighbourhood here, up in Norway, where speeding is reagarded a crime more severe that voilent theft, there is no danger driving in the Cayman with a potential tire-blowout - the car will handle it.)

If I lived in the USA, this might be a good opportunity to go get the big gun and look for someone to shoot after, for instance someone who happens to walk around looking for a pack of screws they lost.
Just make sure not to actually hit anyone.

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2006 Cayman S
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