also serve to indicate wear conditions as the tire tread wears away the studs eventually begin to contact the road surface making a clicking noise that alerts the operator that the tire tread is thin and that the tire needs replacing referring now to the drawings a tire 10 includes a toroidal shell 12 enclosing a hollow interior air space 14 refer to fig3 the tire 10 is mounted on a wheel 16 the rim of which seals the air space 14 the tire shell 12 can be a radial tire constructed of a plurality of radial belts 13 see fig1 covered by an outer layer of rubber 18 which may include a tread designed to grip the road surface and prevent sliding embedded in the outer shell are pluralities of pump assemblies 20 a 20 b valve assemblies 22 a 22 b and stud actuation chambers 24 a 24 b and 24 c all connected by pneumatic lines such as lines 26 a 26 c not all pneumatic lines pump assemblies and stud actuation chambers are shown it being understood that these are distributed about the radial surface of the tire these components may be encased on the outer rubber layer 18 or they may be placed between radial plies or layers 13 still another option is to affix the valve assemblies to the interior surface of the shell with the pneumatic lines.