Method of making tire with tire tread pitch bands

摘要

The tread of the tire of this invention is made using tread bands that have a variable pitch length. That is, the variable pitch length tread bands have a first pitch length on one axial side of the tread band and a second pitch length on the other axial side of the tread band. The transition between the first and second pitch lengths can be a gradual change across the tread band widthwise or a relatively abrupt change. The preferred tire has a tread band where the change in pitch length is widthwise within a groove of the tread. Tread bands of this invention have circumferential edges that mesh with each other such that one variable length tread band can be used with its smaller pitch length on one lateral side of the tread or rotated end to end and used with the smallest pitch length on the other lateral side of the tread of the tire. A method for producing a tread band having a change in the pitch length is also given in this invention. The result is a tire that effectively has twice the number of pitch lengths sequenced around the tire as there are separate tread bands. Reduced tread noise is achieved with a greater number of pitch lengths. Alternately stated, the tread of the tire of this invention has a reduced tread noise when using the same number of different tread bands. A single mold for providing a plurality of variable pitch length tread bands on the molded tire is also within the scope of this invention.