Method of estimating tire contact state, tire contact state estimating apparatus and tire for tire contact state estimation

A tire contact state estimating apparatus detecting a tire contact state of a running tire by using a tire having a tread pattern that a trailing position of a block or a dummy block is formed in a tire circumference direction at a constant cycle, the block is defined by a plurality of circumferential grooves and a lateral groove or a lug groove, and the dummy block projects in a tire axial direction from a land portion continuing in a tire circumference direction comprising:

• a vibration detector that is disposed on a unsprung portion of a vehicle and detects a vibration on a knuckle which is a non-rotatable member and is located on a wheel side than a damping member disposed on a non-rotatable side of the wheel;
• a wheel speed sensor that detects wheel speed;
• a detected frequency band setting unit that sets a frequency band for detecting a vibration level in accordance with wheel speed detected by the wheel speed sensor and the cycle;
• a vibration level detector which detects magnitude of a vibration component in the frequency band set by the detected frequency band setting unit;
• and
• a tire contact state estimating unit which estimates tire contact state in accordance with magnitude of the vibration component detected by the vibration level detector.