Learn about lubes
Grease classification
Grease is classified by consistency using a scale established in the USA by the National Lubricating Grease Institute. The NLGI number describes hardness or softness only — it says nothing about performance level.
NLGI consistency numbers
Consistency is measured by working a grease sample and then measuring how far a standard cone penetrates it, in tenths of a millimetre. A softer grease allows deeper penetration, so the softest grades carry the highest penetration figures and the lowest NLGI numbers.
| NLGI consistency | Worked penetration minimum (0.1 mm) | Worked penetration maximum |
|---|---|---|
| 000 | 445 | 475 |
| 00 | 400 | 430 |
| 0 | 355 | 385 |
| 1 | 310 | 340 |
| 2 | 265 | 295 |
| 3 | 220 | 250 |
| 4 | 175 | 205 |
| 5 | 130 | 160 |
| 6 | 85 | 115 |
Lower numbers are softer, near-fluid greases; higher numbers are stiffer and block-like. Most automotive and industrial bearing applications call for an NLGI 2.
What the NLGI number does not tell you
Because the scale covers consistency alone, two greases with the same NLGI number can behave very differently. When selecting a grease, consider these alongside consistency:
Lithium, lithium complex, calcium and polymer thickeners differ in water resistance, mechanical stability and dropping point. Our range includes lithium and lithium complex greases, and a polymer-based lithium complex grade fortified with graphite for heavy duty adhesive applications.
The base oil viscosity governs film thickness and the speed range the grease suits. High-speed bearings generally need a lower base oil viscosity than slow, heavily loaded ones.
Extreme pressure and anti-wear additives, and solid lubricants such as molybdenum disulphide or graphite, carry shock loads that the base grease alone cannot.
Continuous operating temperature and dropping point determine whether a grease stays in place. High-temperature service calls for a thickener system rated for it.
Our grease range
Five grades, from NLGI 00 semi-fluid through to graphite-fortified lithium complex.
More technical guides
Reference material for choosing and handling lubricants.
API service classification
Engine oil S and C categories, plus the API GL gear oil grades.
Read guide
Viscosity classifications
SAE J300 engine grades, SAE gear grades and the ISO VG industrial scale.
Read guide
Safety & environment
Safe storage, handling, hygiene and disposal of petroleum products.
Read guide