NLGI 2 grease is the most widely used consistency grade of grease, rated on a standardized scale developed by the National Lubricating Grease Institute. It has a texture similar to peanut butter and works well in the broadest range of everyday automotive and industrial applications, which is why equipment manufacturers recommend it more than any other grade.
How the NLGI Scale Works
The NLGI scale rates grease from 000 (nearly liquid) to 6 (nearly solid) based on how firm or soft the grease is. The measurement is straightforward: a standardized metal cone is dropped into a sample of grease that has been worked (kneaded) 60 times at 25°C, and technicians measure how far the cone sinks in tenths of a millimeter. This test follows ASTM D217, and the result is called the “worked penetration” value. A softer grease lets the cone sink deeper, producing a higher penetration number and a lower NLGI grade. A firmer grease resists the cone, producing a lower penetration number and a higher NLGI grade.
NLGI 2 grease has a worked penetration range of 265 to 295 mm/10. For comparison, NLGI 1 grease measures 310 to 340 mm/10 and has a consistency closer to mustard. NLGI 3 is firmer than NLGI 2, while grades 0, 00, and 000 are progressively softer, almost fluid greases used in centralized lubrication systems and cold environments.
What Makes a Grease NLGI 2
The consistency of any grease depends on three components: a base oil, a thickener, and additives. The thickener acts like a sponge, holding the base oil in place so it stays where you apply it rather than running off. The more thickener in the formula, the firmer the grease and the higher its NLGI grade.
Most NLGI 2 greases use a lithium or lithium complex thickener, which has been the industry standard for decades because it handles a wide temperature range and resists water well. You’ll also find NLGI 2 products built on calcium, polyurea, or aluminum complex thickeners for specialized needs, but lithium-based formulas dominate the market.
The base oil can be petroleum (mineral oil), synthetic (such as polyalphaolefin, or PAO), semi-synthetic, silicone, or ester-based. Mineral oil is the most common and least expensive. Synthetic base oils cost more but perform better at temperature extremes and under heavy loads, which is why many premium NLGI 2 greases pair a synthetic base oil with a lithium complex thickener.
Where NLGI 2 Grease Is Used
NLGI 2 is the default recommendation for most general-purpose lubrication. In automotive applications, that includes wheel bearings, chassis points, ball joints, U-joints, and front axle arrangements. If you pick up a tube of multipurpose grease at an auto parts store, it is almost certainly NLGI 2.
In industrial settings, NLGI 2 grease covers an equally broad range: electric motor bearings, conveyor bearings, fan bearings, pillow block bearings, machine tools, presses, forging equipment, and rotary aerators. Heavy equipment like dump trucks, forklifts, front-end loaders, and construction machinery typically runs on NLGI 2 as well. Specialized formulations exist for mining and steel mill equipment, paper mill wet-end bearings, and even food processing machinery (where food-grade H1-rated NLGI 2 greases are used in blenders, filling machines, conveyors, and packaging equipment).
The reason NLGI 2 dominates is balance. It is firm enough to stay in place inside a bearing housing or on a chassis fitting without leaking out, yet soft enough to flow into contact surfaces and provide adequate lubrication at startup. It also handles moderate temperature swings without becoming too stiff in cold weather or too runny in heat.
Performance Tradeoffs by Grade
Choosing the right NLGI grade involves tradeoffs around pumpability, water resistance, temperature stability, and oil retention. NLGI 2 and 3 greases generally offer better water resistance, improved high-temperature stability, and stronger oil retention compared to softer grades. That means the grease stays put longer and resists washing out in wet conditions.
The downside is pumpability. Softer grades like NLGI 0, 00, and 1 flow through centralized greasing systems and long feed lines much more easily. They also perform better in very cold conditions where a firmer grease might not reach the bearing surfaces quickly enough. If your equipment uses an automated lubrication system with long supply lines, the system may require NLGI 0 or 1 rather than 2.
For most manual grease gun applications and standard grease fittings, NLGI 2 pumps without difficulty. It only becomes a concern in extreme cold (well below freezing) or in systems where grease must travel a long distance through narrow tubing.
How to Read a Grease Label
When you buy grease, the NLGI grade is usually printed on the packaging alongside other specifications. A typical label might read something like “NLGI 2, Lithium Complex, EP” (where EP stands for extreme pressure, meaning the grease contains additives that protect metal surfaces under very high loads). Some labels list the base oil type and the operating temperature range as well.
If your equipment manual specifies NLGI 2, stick with that grade. Using a softer grease can cause leakage and insufficient lubrication in applications designed for a firmer product. Using a harder grease (like NLGI 3) may prevent the lubricant from reaching all the contact surfaces inside a bearing. The thickener type matters too: mixing greases with different thickeners (lithium with polyurea, for example) can cause the mixture to soften unpredictably or harden, so it is best to use the same type when regreasing.