US Patent 11760136 Tire with multi-layer insert

A noise damper includes an open cell foam having a circumferential first tier and an interposed circumferential second tier including blocks and voids. The first tier has a radial height that is 3.0-8.0% of a section height and a first axial width. The second tier has a radial height that is 3.0-12.0% of a section height and a second axial width. The blocks span 10-30% of the second tier's inner circumference and the voids span 70-90% of the second tier's inner circumference.