Pneumatic tire

#This invention relates to pneumatic tires and, more particularly, to pneumatic radial tires for trucks, of the type in which there is provided a tread defined by shoulder regions and having circumferentially continuous profiled ribs separated or defined by circumferential grooves.

#It is an object of the present invention to provide a new and improved pneumatic tire such that the truck tire exhibits in operation a high dimensional stability, satisfactory behavior in running in a rectilinear course and nevertheless a particularly high resistance to shoulder wear, while the tire exhibits moreover a satisfactory drainage effect.

#In accordance with the invention, a pneumatic tire comprises a tread defined by shoulder edges and having circumferentially continuous profile ribs defined by circumferential grooves. The axial width of the tread between the shoulder edges comprises only five ribs including two marginal ribs and one central rib of respectively large axial width and comparatively narrower respectively intermediately situated ribs. Each intermediate rib is defined with respect to the central rib by an axially wide continuous circumferential groove and, with respect to the marginal ribs, by a comparatively narrower continuous circumferential groove.

#Referring now to the drawings:

#FIG. 1 is a perspective view of the pneumatic tire constructed in accordance with the invention;

#FIG. 2 is a top view of the FIG. 1 tire; and

#The tire is built in a conventional manner. The tire can be a truck tire having a steel cord radial carcass, steel strand beads, and a steel cord belt. Referring to FIGS. 1 and 2, along its width 2, the tread 1 is defined between its shoulder borders 3 and 4 that are situated in the shoulder regions 5 and 6. From its shoulder borders 3 and 4, the contour of the tire projects substantially radially inwardly in the direction toward the axis 8 of the tire.

#The tread profile is not designed symmetrically with respect to the circumferential central line 7 of the tread, even though the profile elements repeat themselves along each tread half with the same spacing and the same configuration.

#The tread profile shows a particularly wide and circumferentially continuous central rib 9 circumferentially extending in zig-zag shape and provided with projections that enlarge the lengths of the rib edges, as well as with fine slits. The wide central rib 9 is bilaterally defined by likewise unusually wide continuous circumferential grooves 10 and 11 which, in their orientation and in their contour configuration conform essentially to the central rib. The two particularly wide circumferential grooves 10 and 11 are respectively followed by external circumferentially continuous intermediate ribs 12 and 13 which, while they do conform to the central rib in contour and in their zig-zag shaped orientation, exhibit with respect to the central rib a markedly reduced axial width, with the axial width being measured parallel to the axis 8 of the tire.