What Kind of Grease Do I Need?

Consider several factors when choosing the correct grease, including consistency, thickener type, operating temperature, load and more.

February 25, 2021

Several factors influence grease selection, including its consistency and thickener type, along with your operating conditions. Here’s what you need to know to determine what kind of grease you need.

What is grease?

Grease is made up of three basic components:

  • Base oil
  • Thickeners
  • Additives

The National Lubricating Grease Institute (NLGI) uses a grease penetration classification. Chances are you’ve used an NLGI #2 grease before. 

NLGI #2 is the most widespread classification and is used in many automotive and heavy-duty applications, such as ball joints and other suspension components.

Numbers range from NLGI #000, which is the consistency of cooking oil, to NLGI #6, which is like cheddar cheese.

NLGI#PenetrationConsistencyFood Analogy
000445 – 475FluidCooking Oil
00400 – 430Semi-FluidApplesauce
0355 – 385Very SoftBrown Mustard
1310 – 340SoftTomato Paste
2265 – 295“Normal” GreasePeanut Butter
3220 – 250FirmVegetable Shortening
4175 – 205Very FirmFrozen Yogurt
5130 – 160HardSmooth Paté
685 – 115Very HardCheddar Cheese

Grease performance specifications

Consider the appropriate specifications when determining what kind of grease you need. The grease industry also has performance specifications for chassis greases (LA and LB) and wheel bearing greases (GA, GB and GC).

GC-LB signifies the grease meets the most demanding test standards for chassis components and wheel bearings. Greases that meet the GC-LB specification typically also meet most automotive original equipment manufacturer requirements.

What kind of grease do I need?

Factors that affect grease selection include…

  • Thickener type
  • Consistency
  • Dropping point
  • Temperature range
  • Worked stability
  • Oxidation stability
  • Wear resistance

The most important property of any lubricant is its viscosity. Oil viscosity is generally chosen based on the intended application requirements.

A common mistake when selecting a grease is to confuse the grease consistency with the base oil viscosity.

When selecting a grease, you must consider the application, environment, speeds, loads and OEM recommendations.

Here are some popular grease applications and the kind of grease to use.

Grease for roller bearings.

Rotating bearings

This category includes (not limited to)…

  • Roller bearings
  • Plain bearings
  • Thrust bearings
  • Gears
  • Electric motors
  • Presses
  • Winches
  • Bushings
  • Wheel bearings
  • Chassis lubrication
  • Universal joints
  • Ball joints
  • Tie-rod ends
  • Steering knuckles

You’ll commonly find these components in heavy- and light-duty applications found in manufacturing facilities; automobiles; trailers; and landscaping, agricultural and powersports equipment.

General, multi-purpose greases work great, including AMSOIL Synthetic Multi-Purpose Grease, Synthetic Water-Resistant Grease and DOMINATOR® Synthetic Racing Grease.

Bearings operating under heavy-impact loads

These components include (not limited to) heavily loaded…

  • Chassis grease points
  • Wheel bearings
  • Axle assemblies
  • Universal joints
  • Pivot pins
  • Steering linkages
  • Spring pins
  • King pins
  • Ball joints
  • Water-pump bearings
  • Other greased heavy-duty components

These applications require specialty greases formulated for heavy-duty equipment subjected to severe-service conditions. The grease is designed to provide additional protection beyond what a multi-purpose grease provides.

AMSOIL Synthetic Polymeric Truck, Chassis and Equipment Grease and High-Viscosity Lithium-Complex Synthetic Grease are great for these applications.

Grease for heavy-duty equipment.

Non-rotating bearings and sliding applications

These applications include (not limited to) heavily loaded…

  • Pivot pins
  • King pins
  • Bucket pins
  • Fifth-wheel hitch plates
  • Bushings

Greases formulated for these applications are designed to provide the additional protection, impact resistance and tackiness beyond what a multi-purpose grease can provide. They are specialty greases that identify the type of application, such as heavy load bearing, and the extreme conditions common to these applications.

AMSOIL Synthetic Polymeric Off-Road Grease and Synthetic Fifth-Wheel Grease are excellent choices.

Specialty applications

These include equipment used in the food service or pharmaceutical industries. They often require NSF-Approved grease, such as AMSOIL X-Treme Synthetic Food Grade Grease, which is designed for a wide operating temperature range.

Some applications require a grease with exceptional cold-weather pumpability, like arctic drilling rigs. Most grease isn’t designed for extremely low temperatures and have difficulty pumping and protecting in sub-zero cold. AMSOIL Arctic Synthetic Grease is designed to perform and protect at sub-zero temperatures.

Hopefully this helps you determine what kind of grease you need for your application. As always, reach out to AMSOIL Technical Services with questions.

More like this