Jabb,a sweet compromise,is a single opening which allows access to the valve stem and also vents braking air.An image of such a setup is from the Renault Vesta-II,146-mpg concept.The image is in "Other vehicles 1, page -1,line-1,second photo, @-------------------------------------------------------
Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - aerohead's Album: Other vehicles 1 - Picture