What is one of the first signs of bearing failure?

One of the early signs of a damaged wheel hub bearing is a persistent humming noise that increases with vehicle speed while driving; this noise remains consistent during neutral coasting and can typically be clearly heard through the car windows. When the balls or raceways inside the bearing are worn, abnormal friction between metal components generates a rhythmic noise, which becomes more pronounced especially when the speed exceeds 40 kilometres per hour. Simultaneously, the driver may perceive slight vibrations in the steering wheel or vehicle body, associated with operational imbalance due to the bearing's inability to properly support the wheel. If left unaddressed, this condition may further lead to uneven tyre wear, diminished braking performance, and reduced fuel efficiency. It is advisable to perform a lift inspection promptly upon noticing these symptoms, identifying the source of abnormal noise by manually rotating the wheels to prevent safety risks such as wheel lock-up caused by complete bearing failure.