http://money.cnn.com/news/newsfeeds/...11102007-1.htm

note the 12% better fuel economy
this tire might give if made reliable

sample quote:

"
BOULDER CITY, Nev., Oct. 11-- Amerityre Corporation , a leading developer of polyurethane elastomer tire technologies, today announced that it has made significant progress towards successfully completing Federal Motor Vehicle Safety Standard (FMVSS) 139 testing on its Arcus(R) run-flat pneumatic passenger car tire design. The Arcus(R) run-flat tire is a patented system designed to operate at normal air pressure, yet continue to perform normally for at least 200 miles without air. In April 2004, Amerityre successfully completed certification of the Arcus(R) run-flat tire to FMVSS 109, the safety standard for pneumatic passenger car tires in effect at that time. No other company has produced a pneumatic polyurethane passenger car tire that has complied with that standard. Additionally, independent testing demonstrated that the Arcus(R) run-flat tire had 45% less rolling resistance than a comparable rubber run- flat car tire, resulting in more than a 12% increase in fuel economy.
Amerityre is now working to successfully complete the final testing segment, which was not a requirement under FMVSS 109. This segment determines the tire's low inflation pressure performance. In this test the tire is run at 75 mph at a reduced pressure of 20 psi for 90 minutes. The Arcus(R) run- flat tire design has come within 15 minutes of successfully completing this test.

 

That really looks interesting....and you figure....an extra 12% of gas mileage could equal anywhere from 2-5mpg for some vehicles.....

 

Very interesting. I wonder what sort of traction it delivers. A polyurethane tire with super low rolling resistance sounds like it might be slippery.