Trailer Bearing Grease Guide

Trailer Bearing Grease Guide

Trailer grease may not be the most exciting topic, but it is essential to the longevity and safety of your trailer. When it comes to selecting the right grease, it is important to understand the basics of trailer lubrication. This article will help guide you on grease applications so you can enjoy worry-free travel with your trailer.

Types of Grease & Applications

Grease is grease, right? When it comes to trailer applications, not all grease is created equally. The National Lubricating Grease Institute (NLGI) classifies different grease types from #000-#6 based on penetration and consistency. The most common grease available is NLGI #2, typically used in automotive, trailer, and heavy-duty applications. Grease is also classified through ASTM-D4950 with designations of LA and LB for chassis lubrication and GA, GB, and GC for wheel bearing grease. The highest-performance grease would be an LB-GC grease. In this article, we will be mainly focusing on NLGI #2 LB-GC grease. Most greases can be found in synthetic blends and full synthetic formulas. A synthetic blend is typically less expensive, but a fully synthetic grease will offer superior protection and longevity. Another important factor to consider is temperature. A trailer bearing typically operates at temperatures of 140-175 degrees Fahrenheit, so it is crucial to remember when checking grease specifications.

When presented with this information, you may find it to be overwhelming. To help make the process easier, let’s look at some of the common types of grease available and help you understand what grease is best for your trailer.

Multi-Purpose Grease

The most common type of grease available is a multi-purpose grease. This grease type is typically used in low to medium-speed environments. A good multi-purpose grease is cost-effective and convenient, but it is important to check the specifications. A multi-purpose grease may not meet the required temperature ranges and water-resistance properties in which a trailer wheel bearing operates.

High-Temperature Grease

If you operate your trailer in extreme temperature conditions, a high-temp grease may be right for you. High-temp grease provides vital protection in various temperature ranges from extreme cold to extreme hot. It is important to note that not all high-temp greases are resistant to water. If you live in an area that sees extreme weather, use your trailer for extensive high-speed travel, or put your trailer under heavy loads, a high-temperature grease would be best to keep your trailer rolling smoothly.

Marine Grease

When you need superior protection for a trailer that sees underwater use, such as a boat trailer, marine grease is the one for you. Exposure to fresh and saltwater can cause grease to separate and inhibit its ability to properly protect components. Marine grease is specifically designed to provide lubrication even when exposed to water. Read the specifications to ensure it meets the temperature requirements for your needs.

Moly-Blend Grease

All grease includes some form of additive package, but not all grease includes Molybdenum Disulfide, or Moly, for short. While grease with Moly tends to be more expensive, it offers superior protection against wear. Moly provides an extra layer of protection to components that can last even when grease gets low. This additive also helps to provide protection when components are exposed to dirt and dust by coating these contaminants, preventing scoring.

Having an understanding of the different types of grease available is helpful in figuring out which product is best suited for your needs. Be sure to read any specific instructions from your trailer’s manufacturer and assess your trailer’s use when deciding which grease works best.

How to Apply Grease to Trailer Wheel Bearings

It is recommended to grease your trailer’s bearings once a year or before storage if your trailer is used seasonally. Trailer bearings can be found in traditional and EZ-Lube configurations. See our step-by-step guide on how to grease your trailer’s bearings for both types.

Traditional Trailer Bearing Grease Application

  1. Remove the wheel.
  2. Remove the dust cap with either a specialized removal tool or a flathead screwdriver and hammer to pry the cap off.
  3. Remove the cotter pin with pliers or channel locks. Be sure to inspect the condition of the cotter pin. These can be reused if in good condition.
  4. Pull the hub out a little bit. The outer bearing and washer will fall out, so be sure to catch it. Set the outer bearing and washer aside on a clean towel.
  5. Remove the hub fully from the spindle to gain access to the inner seal and bearing on the back. NOTE: if your rear seal is showing signs of leakage, be sure to replace it.
  6. Use a flathead screwdriver or small pry bar to remove the seal and gain access to the inner bearing. Remove the inner bearing and set it aside on a clean towel.
  7. Use a clean rag to wipe off the old grease. Be sure to inspect the condition of the bearing. Deep grooves, rough/gritty feel, and excess noise are all signs of excessive wear and will need to be replaced.
  8. Use a solvent or degreaser to remove the rest of the old grease. NOTE: mixing two types of grease can negatively affect their performance. It is best to clean off all of the old grease to ensure maximum protection.
  9. Begin to pack the bearings with grease. Fill in the front and rear indents and then begin packing the rollers. Once the bearings are properly packed, reinstall them in reverse order of disassembly, starting with the inner bearing.
  10. Reinstall the inner bearing and press in the seal. Gently tap the seal back into place until it is flush with the hub. Once flush, install the hub back onto the spindle.
  11. Reinstall the outer bearing and washer. Reinstall the castle nut onto the spindle. Tighten the castle nut with a wrench or channel locks. Be careful not to overtighten the nut as this can cause damage to the bearings. NOTE: Be sure to follow manufacturer-recommended instructions and torque specifications. Typical reinstallation involves getting the castle nut tight and then loosening a quarter (¼) turn to ensure proper movement of the wheel and hub.
  12. Reinsert the cotter pin into the spindle. If the pin is in good condition, it may be reused. However, it is best practice to replace this component.
  13. Reinstall the dust cover with a few gentle taps with a hammer until properly seated.
  14. Reinstall the wheel and torque lug nuts to the manufacturer's recommended specification.

EZ-Lube Trailer Bearing Grease Application

  1. Remove the rubber grease cover on the face of the dust cap.
  2. Insert the grease gun onto the zerk fitting on the hub and begin to pump in the grease while slowly spinning the hub.
  3. The grease will flow from the inner bearing to the outer bearing until seeping out the face of the hub. Once seepage begins, the process is complete. If you are replacing the old grease from the hub, keep pumping until the new grease becomes visible.
  4. Clean the hub and reinstall the rubber grease cover.


Making sure the bearings on your trailer are properly lubricated is essential in ensuring performance, longevity, and safety. Always make sure to read any manufacturer-specific instructions on how to lubricate your trailer before beginning the process. Trailer bearings typically need to be lubricated once a year, or before storage when used seasonally. Always make sure to use the right grease for your application so you can enjoy worry-free travel wherever you and your trailer go.

Be sure to check out our selection of Hubs & SpindlesBearingsCoversLugs, and more to get your trailer back to rolling smoothly!

Mar 4th 2024

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