okay, so what about the air hubs with the holes leading directly into the tyre cavity. from what i,ve read, the tyres expand at top speed down the straight then deflate to atmospheric pressure when you slow down for a corner.are you sure extra air has got to be pumped into a sealed air tyre. all your doing is creating a hump in the middle that wont go down in corners. you,ve shot yourself in the foot before you race, by allways having less contact patch on the tyres. its not april the first is it. john