Originally Posted by chrisp
Yeah you could be right. I cant see how you can speed rate a tyre valve for example if you fitted one in an 18" rim they would be going round a lot faster than in a 20" rim at 115mph wouldnt they or am i being a bit thick
Wheel speed (number of revolutions) would be the same for a 18 and 20 inch rim the rolling circumference is the same, or very near.
But the speed of the valve passing the pick up would be greater with a larger wheel, because the radius would be greater
Maybe its the centrifugal force thats the problem, crushing or deforming the new type rubber valve at speed
(I used to drag race a bike that used to let its own rear tyre down at speed! Until I found that the valve stem would bend over with the centrifugal force and let the air out.....I changed it for a shorter stemmed valve