Method of estimating the potential friction μ p between a tyre and a rolling surface, said method comprising: - providing a first and a second engaged-friction/kinematic-quantity reference curve, respectively corresponding to a first and to a second reference value μ p1, μ p2 of potential friction with μ p2 >μ p1; - providing a first and a second kinematic quantity threshold value, or a first and a second engaged friction threshold value, said first threshold value corresponding to a kinematic quantity value or, respectively, engaged friction value where said first reference curve is substantially distinguishable from said second reference curve, and said second threshold value corresponding to a kinematic quantity value or, respectively, engaged friction value where said second reference curve is substantially distinguishable from at least one third reference curve corresponding to a third reference value μ p3 of potential friction with μ p3 >μ p2; - determining the engaged friction μ between the tyre and the rolling surface; - determining a current value of a kinematic quantity between the tyre and the rolling surface; - determining a current working point given by the engaged friction μ and the current value of the kinematic quantity; - comparing the current value of the kinematic quantity with the first and the second kinematic quantity threshold value or, respectively, the engaged friction μ with the first and the second engaged friction threshold value; - if the current value of the kinematic quantity or the engaged friction μ is comprised between the respective first and second threshold value and said working point is above said first reference curve, determining that the value of the potential friction is greater than said first reference value μ p1; - if the current value of the kinematic quantity or the engaged friction μ is greater than the respective second threshold value and said working point is above said second reference curve, determining that the value of the potential friction is greater than said second reference value μ p2 of potential friction; - if the current value of the kinematic quantity or the engaged friction μ is greater than the respective second threshold value and said working point is comprised between said first and said second reference curve, determining that the value of the potential friction is comprised between said first reference value μ p1 of potential friction and said second reference value μ p2 of potential friction; - if the current kinematic quantity or the engaged friction μ is greater than the respective first threshold value and said working point is not above said first reference curve, determining that the value of the potential friction is equal to or less than said first reference value μ p1. - providing a first and a second engaged-friction/kinematic-quantity reference curve, respectively corresponding to a first and to a second reference value μ p1, μ p2 of potential friction with μ p2 >μ p1; - providing a first and a second kinematic quantity threshold value, or a first and a second engaged friction threshold value, said first threshold value corresponding to a kinematic quantity value or, respectively, engaged friction value where said first reference curve is substantially distinguishable from said second reference curve, and said second threshold value corresponding to a kinematic quantity value or, respectively, engaged friction value where said second reference curve is substantially distinguishable from at least one third reference curve corresponding to a third reference value μ p3 of potential friction with μ p3 >μ p2; - determining the engaged friction μ between the tyre and the rolling surface; - determining a current value of a kinematic quantity between the tyre and the rolling surface; - determining a current working point given by the engaged friction μ and the current value of the kinematic quantity; - comparing the current value of the kinematic quantity with the first and the second kinematic quantity threshold value or, respectively, the engaged friction μ with the first and the second engaged friction threshold value; - if the current value of the kinematic quantity or the engaged friction μ is comprised between the respective first and second threshold value and said working point is above said first reference curve, determining that the value of the potential friction is greater than said first reference value μ p1; - if the current value of the kinematic quantity or the engaged friction μ is greater than the respective second threshold value and said working point is above said second reference curve, determining that the value of the potential friction is greater than said second reference value μ p2 of potential friction; - if the current value of the kinematic quantity or the engaged friction μ is greater than the respective second threshold value and said working point is comprised between said first and said second reference curve, determining that the value of the potential friction is comprised between said first reference value μ p1 of potential friction and said second reference value μ p2 of potential friction; - if the current kinematic quantity or the engaged friction μ is greater than the respective first threshold value and said working point is not above said first reference curve, determining that the value of the potential friction is equal to or less than said first reference value μ p1.