Gear oils serve as an effective lubricant between all moving parts within a gear system, making sure that the individual gears are always meshing and turning smoothly. While it will always depend on the types of gears in use and the operating conditions involved, a gear oil must have a number of physical attributes to sufficiently protect and lubricate the gears.
Gear oil viscosity
The thickness of a gear oil and other liquids is referred to as its viscosity. While there are many different measurements used for viscosity, the standard option for gear oil and many other automotive oils is the weight classification established by the Society of Automotive Engineers (SAE). The greater the SAE grade number is the more viscous the gear oil will be.
Gear oil temperature
Viscosity is impacted by temperature. The SAE viscosity ratings provided on a product are measured when an oil is 100°C. As oil heats it becomes far less viscous, and as it cools it becomes more viscous (thicker). Those seeking a cold weather oil will find gear oils with an SAE with a “W” certification. This indicates an oil tested at 0°C. The W marking these gear oils stands for winter viscosity.
Gear oil grade
The established SAE grading system displays oil viscosity in numbers ranging from thin oils (10) to the exceptionally thick oils (140 or above). Higher-grade or heavier weight oils are more viscous and thicker as they flow between a system’s gears. For polished, fast, small gears bearing a light load, light grade oil is an ideal option. However, gears that are rough, slow and large under a heavy load require heavy grade oils.
Selecting the right gear oil for your equipment and environment
While this guide to gear oils and their weight can help you select a suitable product for the equipment you use, the best practice is always to consult the original equipment manufacturer’s (OEMs) recommendation. As we mentioned, along with making sure that the gear oil you pick is suited to the machinery you’re using you must also consider the operating environment. Different temperatures have a significant effect on lubricants, and to ensure your gear systems are functioning efficiently, they will need the correct viscosity.