Mineral Oil vs Synthetic For Motorcycles

Some people are as passionate about oils as they are about professional sports or even politics but what’s the real difference between mineral oil and synthetic oil and more importantly does it make a difference for your bike?

Synthetic motor oil starts its life as crude oil, although there are some exceptions but not really worth getting into the detail for our post. With conventional motor oil or mineral oil the refining process is slightly less refined, the oil which is eventually labeled synthetic has had absolutely everything pulled out of the crude oil except for the specific molecules that the oil company has figured out make good engine oil.

An easier way of thinking about the difference between mineral and synthetic is this. Mineral engine oil on a molecular level is made up of a bunch of different sized ball bearings with some tiny rocks and other junk in there.

The rocks and junk aren’t big enough to cause problems so it’s not cost-effective to pull them out, the company then just leaves them in there. synthetic oil though at that same molecular level has no junk and has all the ball bearings the same size sometimes, with extra fancy additives that make it lubricate even better.

In a nutshell, synthetic oils are more expensive because more effort goes into the refining process. So now you might say ok ok enough of the scientific molecular mumbo jumbo, what is the real-world difference between the two?

Viscosity breakdown, this is the only real difference. Viscosity refers to how easily the oil can flow throughout your engine and all engine oils are multi-grade when it comes to this.

For at NW14 viscosity or flow rating, it means the oil has a flow rate of 10 units let’s say at cold winter temperatures and a rating of 40 units under hot conditions, hence 10W 4000 5W30 or any other combinations.

Mineral oils use additives that help the oil stay thin so they flow when cold but maintain their lubrication properties when hot. Synthetic oils, on the other hand, are chemically formulated from the beginning to have a given cold and hot viscosity, this is engineered into the process instead of added on at the end.

This means that additives in mineral oil can vaporize or breakdown and the heavy wear or hot conditions and at the end of its useful life in your engine can get thicker and cold or thinner when hot and will not protect your engine, as well as it, did when it was new.

This is the phenomenon called viscosity breakdown and you’ve probably felt it by having trouble shifting gears when your bike was due for an oil change. If it’s a little more difficult than before to change from first to second or to find neutral, you might just need an oil change.

Synthetic oils suffer a lot less from viscosity breakdown so it’s less likely that your engine will ever go un-lubricated or develop sludge.

Ok ok ok so mineral oil is cheaper but lasts and synthetic is more expensive but lasts longer so then can I change my oil less often?

No, you can’t and this is why. Oil contamination happens when you actually use your bike and not just leave it in the garage while you sit on the Internet.

Smaller particles are going to get in through your air filter, other contaminants are going to get formed by the actual thousands of little explosions and your oil will be giving all of this trash of free rides throughout your entire engine.

You definitely need to change your oil at the same intervals as decided by the manufacturer even if you are using synthetic oil. Synthetic oil will retain its properties longer than mineral oil but it has no defense against contamination.

Okay okay okay okay so give me a straight answer then once and for all, what oil should I use in my bike? Surprise surprise the answer to this has always been a simple one.

If your bike manual specifies the use of a synthetic oil then that’s your only choice, putting mineral oil in a high-performance sports bike that you redline pretty much all the time is not recommended, so use synthetic.

If however, your bike manual specifies mineral or doesn’t specify the type of oil at all then you are free to use both synthetic and mineral, there is no danger here.

Are There Any Benefits in Using Synthetic Oil In An Engine

Are there any benefits in using synthetic oil in an engine that was designed to use mineral oil? Nope, or very few if you are for example going on a long trip and you think you won’t be able to change your oil before you get back and your gearbox gets harder to shift when your bike needs an oil change. Go ahead and put synthetic in there otherwise there are basically no benefits.

Synthetic oils were created for performance machines and if your bike was meant to only use synthetic oil, trust me, you would know about it way before turning to the internet for an answer.

The absolute best way to protect your engine is to change the oil in your engine on time, new oil is better than old oil so turn to your owners manual for the required oil change interval and for the viscosity ratings and stick to that, the rest is fluff so just go and ride

Oh and one more thing. Do not use energy conserving engine oil in your motorbike, if your bike has a wet clutch this piece of info is a lot more important than the whole mineral versus synthetic battle. An energy-conserving engine will cause your wet clutch to slip eventually damaging it so stay away.

What Additives Are Added To Synthetic Oils?

When you see a bottle labeled mineral or synthetic that refers to the base stock that makes up about 75 to 80 percent o each liter of oil, the other twenty to twenty-five percent are additives like anti-foaming agents, anti-wear agents, and viscosity modifiers.

These have a big impact on the oil’s performance. Nearly all additives are synthesized but that’s not considered when categorizing and oil, it’s the base stock that makes a difference and whether or not that base stock was pumped out of the ground and refined or synthesized.

Semi Synthetic vs Fully Synthetic Motorcycle Oil

Making use of semi synthetic oil provides a multitude of benefits for your engine. When it’s time to change your engine oil we strongly recommend that you use a semi synthetic oil, semi synthetic oil is superior in many aspects and offers advantages over conventional mineral oils while being less expensive than fully synthetic formulas.

When your engine runs on semi synthetic oil you benefit from easier starts in cold weather, it also protects your engine much better in extreme temperature conditions and when it runs at high RPM’s it has a better lubricating performance.

Semi synthetic oil provides better protection to your engine from shear and wear, it also offers increased protection for short trips but its superiority doesn’t end there. Semi synthetic oil provides better protection against corrosion of engine parts and produces less residue than conventional oil.

Moreover, semi synthetic oil keeps its lubricating and protection properties much longer and more consistently between oil changes. It is optimal for your car’s maintenance, offer better protection to your engine so go for semi synthetic oil.


Keith Mallinson has been a motorcycle enthusiast for the past 20 years. He has owned a variety of bikes during this time, ranging from sport bikes to cruisers. Keith has a passion for all things motorcycle related, including riding, maintaining, and customizing his bikes. In addition to his personal experience with motorcycles, Keith has also kept up to date with industry news and trends. He enjoys sharing his knowledge and insights with others through his motorcycle blog. When he's not out on the open road, Keith can be found tinkering in his garage, planning his next road trip, or spending time with his family.