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If your bearing starts making noise during operation, there is something wrong with it. There are several root causes associated with bearing noise, and determining which one it is can help you improve your reliability program down the road. With the right condition monitoring applications in place, you can keep operations running smoothly.

What is causing the excessive noise?

Typically, the noise you’re hearing is created when the raceways of the bearing are damaged, causing the rolling elements to rattle during rotation.

Photo credit: Noria Corporation

Given that you know where the noise is coming from, it’s time to determine the root cause, meaning some detective work will need to be performed. The most common causes of a noisy bearing include installation and mounting issues, insufficient lubrication, and contamination.

Improper Installation

Out-of-round housings, dirty surfaces, and rotating shields or seals are often the result of poor installation or mounting conditions. These noises usually present themselves earlier in the bearing’s life.

In the mounting and installation process, it is critical to use proper tools and ovens/induction heaters. Employ a sleeve to impact the entire inner ring face being press-fit and verify the shaft and housing tolerances. If the fit is too tight, you will create too much preload. If the fit is too loose, you will generate too little preload, which may allow the shaft to rotate or creep in the bearing. Also, be sure to check for proper diameters, roundness, and chamfer radius.

Keep in mind that a proper film of lubricant must be established between the rolling elements. Reducing internal clearance and impeding lubricant flow can lead to premature failure. With regards to shaft fit, it is inevitable that there can be a reduction in the radial internal clearance when the bearing is press fit.

Insufficient Lubrication

Inadequate grease volume, the wrong grease, or the wrong viscosity are all lubrication-related problems. Bearing noise could be a result of grease volume dropping too low before relubrication took place. Alternatively, the bearing may have been over-greased at some point, causing failed grease and a lack of lubricant in the cavity. The wrong grease or an incompatible product could also have been used to lubricate the bearing. When choosing grease, be sure to select the right viscosity for the application.


Contamination may also be to blame since this regularly occurs during lubrication practices. Foreign particles may become stuck to the end of a grease gun and enter the machine during relubrication. To avoid this, clean your grease gun before and after each use, or invest in a single-point lubricator to eliminate any chance of maintenance-induced contamination.

How to Prevent Bearing Noise and Failure

Two words: condition monitoring. Continuously monitoring your bearings gives you the best chance of quickly identifying and addressing potential issues. Condition monitoring systems are a great way to keep the health of your machinery under constant review.

The OnTrak uses ultrasound technology to monitor bearing friction and detect the moment grease is needed. It’s supported by the OnTrak IIOT System, a 16 channel IIoT Bearing Monitoring System, and offers access to UE Insights, a cloud-based dashboard, and an alert-deployment platform. This gives you the ability to monitor and precisely lubricate your bearings from anywhere, anytime.

If you’re interested in improving bearing health or condition-monitoring activities, the OnTrak provides an easy way to get started. The system delivers reader-friendly reporting and integrates with your organization’s CMMS, automatically documenting work orders as they are completed. Incorporating this system can drastically improve the state of machines and extend bearing life.