Synthetic vs Conventional Oil - Which Should You Use?

Synthetic vs conventional oil still comes up in discussions. So let's start with some basics to help you understand the difference and the benefits of each type of oil. There are three main types of motor oil: Conventional (petroleum-based oil), fully-synthetic oil and semi-synthetic oil. Knowing when to use synthetic vs conventional oil in your Motorcycle or powersports machine, including side x side, ATV, Snowmobile and Watercraft can mean longer engine life and better performance. The wrong engine oil can lead to decreased throttle response, poor fuel mileage, premature clutch wear (in the instance of a wet-clutch), overheating problems, bearing failures, cylinder wall and cam degradation, stuck piston rings and more.

Comparing Synthetic vs Conventional Oil Types

Synthetic vs Conventional Oil - Suzuki Fully-Synthetic Motorcycle Oil

Petroleum-based or conventional oils are refined to remove impurities. However, some particles still exist since complete refinement is a very expensive process. Because of the various particles in the oil, conventional oil tends to cause a "blanket effect" when the larger particles move toward the outer walls of the oil passages while the smaller particles move more freely through the center.  The "blanket effect" helps to keep the oil cooler, sheltering it from engine heat but it also means that it is not as helpful in cooling your engine since heat doesn't readily transfer to the oil. As motor oil burns off, any impurities in the oil are left behind, clinging to the components of the engine. Over time, the buildup in an engine can cause less fuel efficiency, a decrease in engine performance, top speeds will decline and your bike won't have the same get-up-and-go as it once did. You may also experience clutch slippage.

Fully-synthetic oil is more expensive that the alternatives and consists entirely of man-made components, containing only what the chemists have put into it to improve engine performance and extend the life of an engine. While synthetic oil still contains small particles, they are all uniformly sized which leads to less friction and less heat within the oil itself because all of the particles move through the oil passages at the same rate. With synthetic vs conventional oil, there is no "blanket effect" and the heat from the engine is distributed to the oil, lowering an engine's temperature by as much as 20-50 degrees F. Synthetic oil also has a higher flash point (the temperature at which oil begins to vaporize) than petroleum oil which means it holds up better in higher temperatures.

So what about semi-synthetic oils? These types of oils are typically made up of about 30% synthetic and 70% conventional or petroleum oil. Semi-synthetic oils claim to offer the same benefits as fully-synthetic oils, but for around half the price. Based on what we've discussed above however, while the properties may end up being similar, I'm sure you can guess that the level of deposits left behind will still be significantly higher than a fully-synthetic. This is a happy medium, however, for anyone that needs an alternative to the more pricey fully-synthetic version.

Auto-oil vs Motorcycle Oil 

Automotive engine oil has been substituted for motorcycle oil with little or no immediate problems. But you should note that auto oil is a single-duty lubricant and must work 3x harder to also lubricate the transmission and the "wet-clutch" design inherent in most motorcycles. Automotive oil, therefore breaks down faster than motorcycle oil not only because of the multiple functions it must perform, but also due to the higher temperatures and rev range of a motorcycle engine. Motorcycle oils are designed to lubricate the engine, transmission and wet-clutch as well as to perform at much higher, sustained temperatures. This means they will not break down as quickly, maintain their viscosity longer and limit metal-on-metal engine wear.

Oil Viscosity

SAE Viscosity Chart Chart courtesy of

When selecting an oil, it's helpful to have a basic understanding of the numbers. SAE viscosity grades are 0, 5, 10, 15, 20, 25, 30, 40. 50 and 60. You will sometimes see a "W" after 0, 5, 10, 15, 20 or 25, like 10W30. This stands for "winter" not "weight" as is often believed. The first number stands for an oil's flow rate while cold, while the second number stands for the oil's flow rate while hot. The hotter it is, the higher viscosity rate you're going to need. The chart provides a good representation of what viscosity grades work best at certain temperatures.

In Conclusion

The wrong engine oil can lead to decreased throttle response, poor fuel mileage, premature clutch wear (in the instance of a wet-clutch), overheating problems, bearing failures, cylinder wall and cam degradation, stuck piston rings and more. We recommend that you use a premium, fully-synthetic oil for best performance and prolonged engine life. offers either 20W50 or 10W40 motorcycle oil which is suitable for most riders.

Be sure to consult your owner’s manual for the recommended motor oil specifications for your engine.

Shop: All Motorcycle Oil | Synthetic Motorcycle Oil

Author, J.M. Stickney is a powersports enthusiast working as the Digital Marketing Manager at GearUp2Go. She loves to ride her Suzuki GSX-R600 on the street or at the track. While not on her bike she spends a lot of time outdoors, writing, reading, running or playing with her family.

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