When dealing with oil you might find yourself confronted with various acronyms and terminology the average person may not be familiar with. We therefore thought it might be useful to detail all the motorcycle oil terminology in one place.
Mineral oils (also known as base oils, mineral base oils or lubricant base oils) are chemical substances prepared from naturally occurring crude petroleum oil.
API stands for American Petroleum Institute. In 1970, along with the SAE and ASTM (American Society for Testing and Materials), they established the API Service Classification System to define the performance level of a given oil, unrelated in the main, to oil viscosity.
SAE, the acronym for the Society of Automotive Engineers, is responsible for establishing a classification system based solely on oil viscosity. To classify the oils, their viscosity is measured in cold conditions at different temperatures below zero, and then in hot conditions at 100ºC.
Oil viscosity refers to how thick or thin an oil is. It’s essentially a measure of the oil’s resistance to flow.
Thicker oil (higher viscosity): Flows more slowly and creates a thicker protective film on engine parts, this is beneficial at higher temperatures.
Thinner oil (lower viscosity): Flows more easily, reducing friction and wear during cold starts.
Friction modifiers are essential additives in motorcycle engine oil that help to reduce friction between moving metal parts. Imagine these parts as two metal plates rubbing against each other. Without proper lubrication, they would quickly wear down. Friction modifiers create a protective film on these surfaces, acting like a cushion to prevent direct metal-to-metal contact.
Shear stability is a crucial property of engine oil, particularly in modern, high-performance engines. It refers to the oil’s ability to resist thinning under extreme mechanical stress.
