To provide an estimation method of a road surface state having high followability relative to road surface change besides accurately estimating a state of a road surface on which a vehicle is traveling with a simple constitution, a device therefor and a tire employed for estimation of a road surface state.
A distortion gauge 11 is embedded in a plane orthogonal to a tire circumferential direction inside a block in proximity to a tire equatorial part so as to substantially align the detecting direction with a tire radial direction of the block. A waveform of time change of compression distortion is extracted from detection output of the distortion gauge 11. A peak decrease quantity B of a peak in a tire ground contact surface of the compression distortion waveform is acquired. On the basis of the magnitude of the peak decrease quantity B, the state of road surface on which a tire travels is estimated.
HAGIWARA KAZUMASA