I was working out in my garage when I noticed the right rear tire looked a little soft. I measured the pressure to be 9 psi! 3/4 below the 36 psi specified by Porsche.

Well, I jacked up the car and removed the tire and put it in my Explorer. The next day I called my mechanic and asked for a recommendation where to take it. He normally fixes these things, but he was leaving for Sebring to race so he gave me some words of advice. After a successful repair, I wanted to share it with the club at large in case you find yourself in the same situation.

1. Ask the tire shop if they have had experience with Porsche rims.
2. Ask if they use a special head on the tire machine to protect against damage to your alloy rims.
3. Ask to see the shop, the tire machine and the special head used to protect alloy rims.
4. Ask if they plug, patch or use a combination of both.
5. Ask if have the adhesive weights or Teflon coated weights to prevent damage to your rims.

If any answers to these questions is no, maybe or “ well you see, what it is, is……”. Then thank them and briskly walk away.

In point #4, tires used to be simply plugged. A soft rubber piece is thread through a large metal needle and inserted into the hole left by a nail or object that punctured the tire. A chemical reaction stiffened this plug and the tire held air and you were sent on your way. However, at any time, speed or situation, the plug could pull out and your tire could blow out all together.

The patch is reminiscent of inner tube patches used on bicycles. The tire is dismounted and placed on a device the stretches open the inner tire beads so the mechanic can access the damaged area. A cement is applied to soften the rubber and a thick patch of rubber is applied to the damaged area with more cement and the edges of the patch is coated with cement to assure no air can leak out. The patch is held under pressure until the cement cures (about 20 min). Then the tire is mounted back on the rim and filled with air, re-spun balanced and you are on your way.

The newest innovation combines both methods with a patch that looks like a valve assembly; A large rubber protrusion with a flat back. The stem is pushed through the damaged area and then pulled from the other side until the flat part comes close to the inner tire. Cement is applied to the flat portion and to the stem. Pressure is applied to back of the flat piece of the patch until the cement cures. The excess stem is cut flush to the tire tread and will wear with the tire tread. Then the tire is mounted back on the rim and filled with air, re-spun balanced and you are on your way.

I brought my flat Pirelli P7000 to a national tire chain store in Glen Burnie and had a very good experience. They hit every point in the above list and even let me watch the process in their shop. The tire still holds accurate pressure and is in excellent shape. If you would like to know the name of the shop, please feel free to call or e-mail me.

One caveat to this article; if the damage is close to or in the sidewall of the tire, the tire will be not repairable and you will have to purchase a new one. The sidewall and edges of the tread flex heavily during operation and any patch or plug will not hold under those conditions. If you use an online company for your tire purchases, make sure your tire shop will accept and mount your selection.

Safe driving!

John D. Patterson