Watch the video above or read on below to learn about the differences between 10W-30 and 10W-40 motorcycle oils.
What Do the Numbers Mean?
Both 10W-30 and 10W-40 are multi-grade engine oils, which means they carry properties of different weight oils, depending on the conditions.
The first grade of the motor oil is the number before the W, and the second grade is the number after the W.
The second number after the W is where the slight difference is found in these oils. That number represents the oil's viscosity at temperatures above 212° F or 100° C. The higher the number, the thicker the oil is at higher operating temperatures. So the 10W-40 oil is a tad thicker than the 10W-30 oil when the engine is hot, meaning it offers a little more protection.
Both of these oils are good for cold starts, but if you're in a warmer climate or your engine runs a little bit hotter, the 10W-40 oil is the way to go. However, if you live somewhere colder or your machine’s engine runs cooler, the 10W-30 works better, since it runs a little thinner in cooler temperatures.
10W-30 vs 10W-40 Fuel Economy
When it comes to fuel economy, the flow of oil adds drag inside your motorcycle’s engine. A thinner oil produces less drag, which increases fuel efficiency, so a 10W-30 oil offers better fuel economy than the 10W-40 oil.
However, choosing a motorcycle oil based on whether it offers better fuel efficiency is a mistake. You should only choose the oil based on what’s best for the motorcycle’s engine and operating conditions, not fuel economy.
Can You Use Both 10W-30 vs 10W-40 Oil?
So is it safe to use either oil in your motorcycle? Yes, but it's best to use the oil recommended by the manufacturer for your motorcycle’s conditions. Either grade will work, but you should choose a motorcycle-specific oil so that your machine’s clutch is protected.
Additives in car oils also use friction modifiers that can negatively impact the engagement of your motorcycle's clutch, so using an automotive oil in a motorcycle is not recommended.