Brake assist system for a cyclist on a bicycle by a haptic feedback, comprising: - a first sensor for measuring the angular speed (ω 1) of a first bicycle wheel, suitable for generating a signal representing the first wheel angular speed; - a second sensor for measuring the angular speed (ω 2) of a second bicycle wheel, suitable for generating a signal representing the second wheel angular speed; - an actuator applicable to a bicycle portion suitable for producing vibrations; - a control module configured for: - receiving at the input the signals representing the angular speeds (ω 1, ω 2) of the first and second wheels; - generating a command signal of the actuator so that the actuator vibrates at a vibration frequency (f), wherein said vibration forms said haptic feedback for the cyclist, characterized in that the control module is further configured for: - determining a variable representing the slip and/or deceleration of the first wheel (A, e λ, e η, e ε), or the risk of flipping over the bicycle around said first wheel based on at least said angular speeds (ω 1, ω 2) of the first and second wheels; - determining said vibration frequency (f) of the actuator based on said variable representing the slip and/or deceleration of the first wheel (λ, e λ, e η, e ε) or the risk of flipping over the bicycle around said first wheel. - a first sensor for measuring the angular speed (ω 1) of a first bicycle wheel, suitable for generating a signal representing the first wheel angular speed; - a second sensor for measuring the angular speed (ω 2) of a second bicycle wheel, suitable for generating a signal representing the second wheel angular speed; - an actuator applicable to a bicycle portion suitable for producing vibrations; - a control module configured for: - receiving at the input the signals representing the angular speeds (ω 1, ω 2) of the first and second wheels; - generating a command signal of the actuator so that the actuator vibrates at a vibration frequency (f), wherein said vibration forms said haptic feedback for the cyclist, characterized in that the control module is further configured for: - determining a variable representing the slip and/or deceleration of the first wheel (A, e λ, e η, e ε), or the risk of flipping over the bicycle around said first wheel based on at least said angular speeds (ω 1, ω 2) of the first and second wheels; - determining said vibration frequency (f) of the actuator based on said variable representing the slip and/or deceleration of the first wheel (λ, e λ, e η, e ε) or the risk of flipping over the bicycle around said first wheel. - receiving at the input the signals representing the angular speeds (ω 1, ω 2) of the first and second wheels; - generating a command signal of the actuator so that the actuator vibrates at a vibration frequency (f), wherein said vibration forms said haptic feedback for the cyclist, characterized in that the control module is further configured for: - determining a variable representing the slip and/or deceleration of the first wheel (A, e λ, e η, e ε), or the risk of flipping over the bicycle around said first wheel based on at least said angular speeds (ω 1, ω 2) of the first and second wheels; - determining said vibration frequency (f) of the actuator based on said variable representing the slip and/or deceleration of the first wheel (λ, e λ, e η, e ε) or the risk of flipping over the bicycle around said first wheel. - determining a variable representing the slip and/or deceleration of the first wheel (A, e λ, e η, e ε), or the risk of flipping over the bicycle around said first wheel based on at least said angular speeds (ω 1, ω 2) of the first and second wheels; - determining said vibration frequency (f) of the actuator based on said variable representing the slip and/or deceleration of the first wheel (λ, e λ, e η, e ε) or the risk of flipping over the bicycle around said first wheel.