that has a fixed offset height h one method of attaching the contact surface 144 to the lever arm 130 as illustrated in the figures uses an extension piece 142 connected at one end to the fulcrum end 140 of the lever arm 130 and at the other end to the contact surface 144 it should be understood that a wide variety of alternative connections between the contact surface 144 to the lever arm 130 are contemplated as within the scope of the invention for example another form of the lever arm assembly includes using a construction where the lever arm and the contact surface are directly connected to each other without the use of an extension piece also the entire assembly of the lever arm and contact surface could be formed as a single construction for instance as a single molded part a typical valve stem 200 is illustrated in fig4 the valve stem body 210 is typically a rubber material and is designed to extend through the opening of a tire rim 300 as illustrated in fig3 a the valve stem body 210 extends to a threaded tip 230 at the top at the bottom of the valve stem is an expanded base 220 that is designed to seat against the back of the rim opening when the valve stem 200 is properly installed in.