The Difference Between Motorcycle 10W30 and 15W40
2 Answers
The difference between motorcycle 10W30 and 15W40 lies in three aspects: Different Applicable Temperatures: 10W30 is suitable for temperatures ranging from -20°C to -30°C, with a maximum limit of -30°C. It is suitable for naturally aspirated turbocharged diesel engines and can effectively reduce wear; 15W40 is suitable for temperatures ranging from -15°C to -20°C. Different Viscosity Grades: 10W30 has a higher viscosity grade; 15W40 has a lower viscosity grade. Different Applicable Seasons: Both 10W30 and 15W40 are multi-grade oils. 10W30 is only suitable for winter use; 15W40 can be used in winter, spring, and autumn.
I've been riding motorcycles for several years, and every time I change the oil, I struggle between using 10W30 or 15W40. Simply put, the number before the W indicates low-temperature performance—a smaller number is better for cold starts. For example, 10W30 makes it easier to start the bike quickly in winter, ensuring a smooth ignition. The number after the W represents high-temperature viscosity, with 40 being thicker than 30, providing better engine protection in hot weather. I find 10W30 hassle-free during spring and autumn, but when summer heatwaves hit, the engine feels a bit sluggish. Last year, I switched to 15W40 during hot weather and noticed stronger acceleration and less worry about long-term wear. However, it depends on the bike model and usage conditions—my old bike’s manual recommends 15W40, so I now switch oils seasonally. When new riders ask me, I advise them to check the manual first and avoid random changes to prevent engine damage. In short, choosing the right oil ensures a safer and more comfortable ride.
