What Kind Of Grease Is Best For Trailer Wheel Bearings?


As you likely already know, not all greases are created equal.

Some trailer bearing grease can withstand high temperatures, while others may be better at resisting water and other contaminants.

So how do you choose the right grease for your Trailer Wheel Bearings?

Here is everything you need to know, in order to make the best bearing grease choice for your trailer application.

Did you know that almost 70% of grease on the market today is referred to as lithium soap-based grease?

What Is Lithium Soap-Based Grease?

Lithium grease is a highly versatile, multipurpose grease that was invented in the 1940s.

This type of grease contains mineral or synthetic oil and hardened castor oil fatty acids that are called lithium stearate or lithium salt. Lithium soap is, essentially, known as the thickener that turns the base oil into grease. With that said, it is best to compare lithium soap-based grease to those using other thickeners, such as sodium and calcium soap thickeners.

Lithium Soap-Based Grease:

  • Has a wide temperature range
  • Is very mechanically stable
  • Has a high water resistance

Is Lithium Grease Good For Trailer Bearings?

In almost all trailer applications, lithium soap-based grease is the preferred bearing grease.

The Advantages Of Lithium Grease

In most cases, a lithium soap-based grease is going to offer so many advantages that the additional cost is easily offset by increased performance.

  • A high dropping point of 190°C - 200°C (374°F - 392°F)
  • A good low-temperature function, depending on the base oil
  • Perfect for tapered roller bearings
  • High water resistance
  • A high degree of shear stability
  • Exceptional thermal stability
  • Long-term storage stability
  • A long useful life
  • Pumpable
  • Smooth structure
  • Available as an extreme pressure (EP) grease with high load and anti-wear abilities

The Disadvantages Of Lithium Grease

While lithium soap-based grease does have a long list of benefits for your trailer wheel bearings, it also has a few disadvantages, as well.

  • Due to the high production and raw material costs, lithium grease is more expensive than other bearing greases.
  • Calcium greases have a higher water resistance than lithium grease.
  • Anti-corrosion additives are particularly needed.

How Do I Know If My Trailer Wheel Bearings Need Grease?

It is important that you grease your Trailer Wheel Bearings periodically. Not only that, but your trailer bearings need regular maintenance to ensure a safe and reliable operation.

To assess the condition of your trailer's wheel bearings:

01. Do a Visual Inspection

Look for any signs of grease leakage. Bearing grease leakage can indicate that the seals are damaged or that the bearings are overfilled with grease.

02. Check for Unusual Noises

Listen for any unusual noises that are coming from the wheels. If you hear grinding, squeaking or rumbling sounds, it could be a sign that the bearings are dry and need lubrication.

03. Examine for Wheel Play

Jack up your trailer and see if there is any noticeable wheel play or wobbling. If so, it may indicate that the wheel bearings are loose or damaged.

04. Rotate the Wheel

With your trailer wheel off the ground, try spinning it by hand. A smooth and free rotation with minimal resistance is a good sign. However, if you feel any roughness, resistance or hear unusual sounds, the bearings likely need attention.

05. Check the Hub Temperature

After towing your trailer for a short distance - without overheating the bearings - touch the wheel hub carefully. Your trailer’s wheel hub assembly should be warm, but not excessively hot. If the hub is very hot to the touch, then it could be a sign of bearing issues, which includes insufficient lubrication.

06. Remove the Wheel

If you suspect bearing problems or just haven't checked them in a while, it may be a good idea to remove the wheel and access the bearings directly. That way, you can do a more thorough inspection.

07. Inspect the Bearings

  • Remove your trailer's hub cap (if applicable) and the cotter pin or retaining nut. Make sure that you carefully slide the hub off the spindle.
  • Inspect your trailer wheel bearings for any visible damage, wear or discoloration. Excessive heat can eventually cause the bearings to turn blue, which is a sign of overheating.
  • Check the condition of the bearing for pitting or wear.

What Happens If You Don’t Grease Trailer Wheel Bearings?

Neglecting to grease your trailer wheel bearings or even allowing them to run dry can, ultimately, have serious consequences. Not only for the performance of your trailer, but also for your safety while towing.

Here are some of the potential problems that can occur, if you do not properly grease your trailer bearings:

  • Increased Friction and Heat: Bearings require lubrication, in order to reduce the friction between the components. Without grease, the metal surfaces are going to rub against each other and generate heat. This heat buildup can essentially cause the bearings to overheat, which will lead to premature wear and, in extreme cases, bearing failure.
  • Bearing Wear: The lack of lubrication will eventually accelerate the wear and tear on your trailer bearings. Over time, this can lead to pitting, scoring or even complete degradation of the bearing surfaces. Worn bearings are more likely to fail and can even result in costly repairs.
  • Reduced Bearing Life: The bearings' lifespan is going to be significantly shortened if not adequately lubricated. This can lead to frequent maintenance and continuous replacement, which increases your overall maintenance costs.
  • Safety Risks: Trailer bearings play a critical role in the safe operation of your trailer. If they fail due to insufficient lubrication, it can result in catastrophic consequences - such as a wheel separation, loss of control or even a trailer accident while in transit.

When You Properly Grease Your Trailer Wheel Bearings

If you apply a suitable and high quality bearing grease and lubricate your trailer bearings accurately, you are going to:

  • Reduce friction
  • Prevent excessive heat buildup
  • Extend the bearing life
  • Experience a smoother operation
  • Improve fuel efficiency
  • Enhance safety
  • Reduce maintenance costs

ReliaBull has a wide selection of quality trailer products, including trailer wheel hub kits, U-bolt kits and bearing kits.

Contact us today to improve your trailer's performance with highly qualified trailer parts.