Why bearings need to be re-lubricated
Maintaining bearings is essential for optimal performance and to increase the lifespan of a bearing. Overtime grease breaks down and deteriorates making the bearing susceptible to failure. Keeping bearings lubricated with new high grade grease helps reduce metal to metal friction that can cause premature wear. Another added benefit is the grease protects the bearings from corrosion and contaminates.
New bearings off the shelf
It's standard today that most bearing manufacturers pre-grease the bearings. All of the mounted bearings we offer are pre-greased with a lithium based NLGI #2 grease. Bearings are pre-filled anywhere from 30% to 40% with grease, however the pre-fill amount can vary by manufacturer. Wondering why bearings are not pre-filled more or even completely full? Filling a bearing 100% is just as bad as under lubricating a bearing. The biggest issue of overfilling a bearing is it will cause the bearing to overheat. When a bearing overheats it can cause pressure buildup making the bearing work twice as hard. Overheating can also cause permanent damage the seals and ti will rapidly deteriorate the grease.
General guideline for re-lubricating mounted bearings
Maximizing the service life requires that you re-lubricate the bearing at set intervals based on the application and conditions. Below is a general guideline chart that shows the intervals a bearing should be re-lubricated. There are many other conditions and factors that will affect how often you need to re-lubricate.
| dn Value* | Environmental Conditions | Operating Temperature | Intervals |
|---|---|---|---|
| Up To 40,000 | Ordinary | 5°F to 150°F | 6-12 Months |
| Up To 40,000 | Ordinary | 150°F to 210°F | 2-6 Months |
| 40,000 To 70,000 | Ordinary | 5°F to 150°F | 2-6 Months |
| 40,000 To 70,000 | Ordinary | 150°F to 210°F | Monthly |
| Up To 70,000 | Dirty | 5°F to 150°F | Weekly To Monthly |
| Up To 70,000 | Dirty | 150°F to 210°F | Daily To Weekly |
| Up To 70,000 | Very Dirty | Any | Daily |
Bearing grease types & amounts
Its recommended to use a lithium based NLGI #2 grease, which is suitable for most applications. The chart below is a general guideline that lists the amount of grease based on the bore size of the bearing. However, grease amounts may vary based on your application experience. Temperatures over 210°F & under 20°F should use a special formulated grease. Grease should be added under low pressure with the shaft slowly turning to distribute the grease evenly. Bearings should never be completely filled.
| Bore size | Grease Amount |
|---|---|
| 5/8” Up To 1” | 1.5 – 2 Grams |
| 1-1/8" Up To 1-1/2" | 2.5 – 3 Grams |
| 1-7/16” Up To 2-7/16" | 4 – 5 Grams |
