Trailer Lubrication: Can I Change from Oil Bath to Grease on my Hotshot Trailer?
The service department at the Nationwide Trailers location I manage in Pasadena Texas gets this question from customers frequently. They have a hotshot trailer with oil bath-type axles. They ask if they can switch to using grease instead. The short answer is Yes. I’ll share a little more about when and why you might want to make that switch and the pros and cons of each lubrication system.
What is the Benefit of Grease Over Oil?
While there are certain situations where oil is the better choice, lubricating bearings with grease is the preferred choice for over 80% of our hotshot customers. Many choose grease because it doesn’t leak the way oil will. Worn seals will not leak as easily with grease. Leaking oil can cause damage to other components such as brakes.
Grease Will Last Longer
Because of its higher viscosity, grease will stay in place longer than oil. Grease is the preferred option when longer life is needed. Grease consists of about 85% mineral or synthetic oil with thickeners rounding out the rest of the grease volume.
What is the Benefit of Oil over Grease?
The most common reason for using oil for your trailer’s axle bearings is for long haul driving. Over long distances or hauling heavy loads, your bearings will reach a very high temperature. Because oil can flow more freely, it can transfer heat away from working bearing surfaces. This makes oil lubricants more efficient in these high speed, high temperature conditions.
Maintenance of Axle Bearings for Hotshot Trailers
Oil can be changed without much disassembly of hardware. Repacking grease requires increased labor which increases cost and downtime.
Oil volume is easier to measure as compared to grease. Level gauges or sight glass allow you to monitor oil levels. Grease in not as easy to check. This can be a problem as over or under-greasing can cause bearing failures.
Re-greasing vs Changing Oil
Most mechanics will tell you that for oil bath hubs you do not need to change the oil at any particular interval. As long as there is no leaking it should be left alone. However, if the oil has a milky appearance it should be changed.
Re-Greasing intervals that will always provide the proper amount of oil to bearings cannot always be accurately predicted. We do know that a proper interval is mainly a function of operating temperature, the number of hours per day, and the size and speed of the bearings. Some trailers need grease added to bearings every two weeks, some once a month, and some every three months. In applications such as this, it is often beneficial to completely wash out the bearings once a year, re-pack with new grease, and continue with the established re-greasing program.
So the answer to the question is still yes, a hotshot trailer using oil bath axles can switch to grease. The best choice depends on your trailer usage and even your preference.