I was thumbing through the Longacre catalog today, and noticed something neat, and I wanted to know ya'lls' two cents on these. I have never seen these. They are Longacre Tireliefs, and what they do is, relieve tire pressure builup as you race automatically. I would imagine that you can set these to release at your desired pressure. They are lightweight, at 9grams and the catalog says that they won't affect your wheel balance. They are sold in sets of 4, for $59.95; part #5000. Here's the link at their website:
http://www.longacreracing.com/catalo...t.asp?catid=20

It looks interesting.