In reply to ChrisJD:
Except it isn't the same idea at all. Its a tubeless system with 2 chambers to allow for differential inflation. A low pressure chamber at the tread for improved traction and a high pressure one next to the rim for snakebite protection.
Robert Millar used to do what was suggested in the other thread. He said it made the rolling resistance very high and so was great training value and made his race set up feel even faster.
