MC Garage Video: Mineral Oil vs. Synthetic Oil For Motorcycles

What’s the difference between mineral oil and synthetic oil, and what does it mean for your motorcycle?

Some people are as passionate about oil as they are about professional sports or politics. But what’s the real difference between mineral oil and synthetic oil, and more importantly, does it make a difference for your motorcycle?

A mineral or synthetic designation refers to the base oil that makes up about 75 to 80 percent of each liter of oil. The other 20 to 25 percent of the bottle are additives like anti-foaming, viscosity modifies, and friction modifiers. Nearly all additives are synthesized in a lab, but they’re not considered when categorizing an oil. It’s the base oil that makes the difference, and the American Petroleum Institute has split them up into five groups based on their characteristics and composition.

Group I, Group II, and Group III oils are all derived from crude oil that’s pumped out of the ground, while group IV and Group V oils are synthetic, meaning they’re concocted in a lab from chemically modified materials. Group IV is reserved for a specific type of chemistry called Polyalphaolefins, or PAOs. Group V includes a pretty wide range of chemistries, but the most popular Group-V synthetics are esters.

So, the base oil determines if an oil is classified as mineral on synthetic, but what do those terms mean for your engine, and what are the pros and cons of each?

Mineral oil has been around for decades and it can offer great lubrication performance. By far the biggest appeal of mineral oil is its price. Since it takes less work to become a finished product, it’s pretty affordable stuff.

The drawbacks of mineral oil stem from the fact that it’s refined from crude oil. That means mineral oil contains a variety of different molecules as well as some lingering contaminants like sulfur. Basically, that means mineral oil is less chemically stable than synthesized oil so it’s more easily oxidized and acidified and can break down more quickly under extreme use. And by “extreme” we mean high loads, high engine speeds, and high temperatures. Think motocross bike being ridden at full tilt on a scorching summer day.

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Just as the cons of mineral oil revolve around its impurities, the benefits of synthetic oil revolve around its purity. Synthetic oil consists of uniform molecules that are specifically tailored to serve as a performance lubricant. That means it does a better job of reducing wear and holds up better under extreme use. The cons? There’s really just one: Price. Synthetics are difficult to produce, and the cost reflects that. We’re talking $15 a liter versus about $6 a liter for this mineral oil.

Torn between the two? Semi-synthetic oil is a mixture of mineral and synthetic oils. It offers some of the benefits of synthetic oils without all the cost. The thing is, there is no set minimum percentage for synthetic content, so semi-synthetic oils can range from as little as 5 percent synthetic on up to a straight 50-50 blend. For the most part, though, semis use about 15 percent synthetic oil.

So the bottle will say what base oil it’s made from, right? Not likely. The only time you really know you’re getting the good stuff is when you see “ester” on the bottle. Ester isn’t your great aunt, it’s a family of badass molecules that have some impressive properties like polarity and super-strong film strength. And since it’s the most expensive stuff to make, manufacturers are always eager to slap “ester” on the label.

When it comes down to it, there’s a lot of marketing that goes into oil and it can be difficult to really know what you’re buying. Our advice? Buy oil from a reputable, established company and steer clear of no-name bargain brands.

The type of oil you use can be a tough choice, but when it comes down to it changing your oil regularly is just as important as what oil you use.

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