Bearing Lubrication: NLGI Grades, Base Oils, and Relubrication Intervals

Most bearing failures are lubrication-related. Matching the grease to the operating conditions is the single most effective way to extend bearing life.

NLGI Grade

The NLGI grade describes grease consistency. NLGI 2 is the most common general-purpose grade; NLGI 3 suits higher speeds and vertical applications, while NLGI 0 and 1 are used where low-temperature flow is needed.

Base Oil

Mineral base oils are economical and cover most applications. Synthetic base oils (PAO, ester, silicone) hold up better at high and low temperatures and resist oxidation, making them the choice for severe duty.

Relubrication Intervals

Relubrication frequency depends on speed, temperature, and load. Higher speeds and temperatures shorten the interval. Over-greasing is as harmful as under-greasing, so follow the manufacturer's interval and quantity.

RBC Industrial carries a full range of bearing greases and can help you select the right NLGI grade and base oil for your application.