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Mineral Oil vs Synthetic Oil For Motorcycles: Which Is Better?

The mineral oil vs synthetic oil debate is a hotly contested one with valid arguments on each side. The answer isn’t the same for everyone, and each case needs to be looked at for the best solution. This means it can be hard to know if mineral oil or synthetic oil is better for your motorcycle.

Synthetic oil is far superior to mineral oil for motorcycles, but the performance increase comes at a hefty price difference of up to 4 times more. With such a large difference in price, you need to evaluate if the performance difference is worth it for your specific bike.

With such a large cost disparity, it makes sense to scrutinize the advantages and disadvantages of both types of oil to find out what is best for you. Keep reading as we put the pros and cons of each type of oil under the microscope and explain which is the best for your motorcycle.

What Is Mineral Oil For Motorcycles?

Mineral oil for motorcycles is refined crude oil that has been treated to have the viscosity, flow, and temperature properties needed to lubricate an engine. Mineral oil has better cooling and overall protection for older engines but with the consequence of poorer acceleration.

Mineral oil is ideal for a low budget as its price is much lower compared to synthetic oil, however, the life of the oil is also shorter. The viscosity value of your oil is key. Check your motorcycle manual to find out which oil has been recommended by the manufacturer during its run-in period and after. High rpm engines require specialized oil and mineral oil cannot be substituted in its place.

What Is Synthetic Oil For Motorcycles?

Synthetic oil for motorcycles is created from man-made chemical compounds designed to exhibit the properties required for engine lubrication, but the base oil is always high-quality mineral oil. Synthetic oil can withstand very high temperatures ranging from around 400 to 700 degrees Fahrenheit.

Synthetic oil has fewer impurities and so also has lower emissions. The oil is made using a specific blend of various oils and additives with precise ratios thereby creating synthetic oil that has specific properties and can be reliably manufactured. Of course, for those who don’t mind spending the extra money to buy synthetic oil, the fact remains that it is worth every penny.

Mineral Oil vs Synthetic Oil – 3 Key Differences

1. Mineral Oil Breaks Down At Lower Temperatures

All oils eventually break down at high temperatures, but mineral oil breaks down at around 270 degrees Fahrenheit. The oil exhibits changes of increased viscosity as well as darkening of color. Increased viscosity brings about a reduction of its lubricative properties, thereby causing the engine to run hotter.

Synthetic oils also break down, but at much higher temperatures, making them more suited for engines that run at high revolutions per minute with extremely high power-output. Since these oils can withstand higher temperatures, their life is also longer.

Engines are becoming smaller as manufacturers strive to improve fuel efficiency and the use of turbochargers is commonplace.All of this means increased lubrication requirements that can only be met by synthetic oils because the engines run hotter and faster. As the engine gets hotter the oil flows more easily until its temperature ceiling is reached, after which it breaks down or evaporates.

2. Oxidizes Faster

The oil that cannot withstand high temperatures oxidizes and acidifies faster. Each cycle of oil heating up and cooling down adds some oxidation to it. Typically, mineral oil needs to be changed every 3,000 to 5,000 miles depending on driving style and driving conditions. Synthetic oil is rated for 7,500 miles to 20,000 miles or 1 year, depending on which comes first.

The worst contaminant of mineral oil is sulfur which causes it to acidify over time. Most contaminants of mineral oil cannot be removed completely during manufacturing, on account of this, the final product contains them in minuscule quantities. Once inside the motorcycle and subjected to endless cycles of heating and cooling, they solidify into tiny particles that affect the lubrication.

When old mineral oil is drained out from a motorcycle gearbox, it is usually blackish sludge. This happens as mineral oil gets oxidized very fast which causes the darkening of its color. Any impurities in the oil also contribute to the color change. The base oil makes all the difference, so additives can only slow down the process.

3. Oil Purity

The oil purity of synthetic oil is much higher because it does not use as much mineral oil as its base. The synthetic oils that are added to give it its enhanced properties are strictly controlled during manufacturing processes to ensure that impurities are filtered out. Mineral oil has a much higher percentage of impurities as the basic oil contains them and they are very difficult to remove.

Do not wait until the specified number of miles has been crossed as the best defense against most of these problems is to change the oil at regular intervals. Another approach is to drain out a small quantity of oil, inspect it for sludge, then take action as needed.

Mineral Oil vs Synthetic Oil: Which Is Better For Motorcycles?

Synthetic oil is better for motorcycles, especially for high-performance engines that run at higher temperatures. It can last 2-3 times longer than mineral oil, offsetting the higher cost. Scooters or low powered bikes can be better off using mineral oil as the engines don’t run as hot.

The oil viscosity needs to remain the same over a wide range of operating temperatures, but some oils do not flow until a certain temperature is reached. In the winter months when the engine is cold, the oil takes time to start moving through the engine to lubricate its parts. Synthetic oil is engineered to flow easily at lower temperatures to protect the engine right from the start.

An important fact for motorcycle owners to make note of is that many motorcycle manufacturers ship new motorcycles with mineral oil in the gearbox. This is because, during the running-in period of the engine, the piston, cylinder, and piston rings get set better with mineral oil. Using synthetic oil during the run-in period does not provide the same benefits.

Lasts Longer With Higher Fluidity

Synthetic oil lasts much longer than regular mineral oil. This difference can be significantly larger under higher temperatures when it can outlast mineral oil by 2 to 3 times in terms of miles traveled. Mineral oil breaks down or degrades, while synthetic oil retains its lubricative properties. This offsets the higher cost of synthetic oil as it needs to be changed less often.

In colder temperatures, it takes time for mineral oil to warm up so that it circulates around the key moving parts of the engine to provide essential lubrication. Synthetic oil moves much more freely, even at lower temperatures, providing lubrication for the engine right from the start.

High Powered Engines

Synthetic oil is a must for motorcycles that are performance oriented. They produce very high power and acceleration by using engines that run at very high revolutions per minute, generating a lot of heat in the process. Not many bikes have turbochargers, but those that do must use synthetic oil for lubrication.

Turbocharger oils can reach temperatures above 400 degrees Fahrenheit while the shaft rotates at 200,000 revolutions per minute. At such high temperatures and speeds, it is crucial that they receive sufficient lubrication else the engine will be permanently damaged. Many oils break down under turbo conditions to leave deposits inside the engine.

Most motorcycle manufacturers do not add turbochargers to regular motorcycles as they require heavier bikes and need to dissipate a lot of heat, but there are a few. A turbocharger can add up to 60 horsepower by way of added efficiency, which explains its popularity.

Many bikes have added custom turbochargers to improve their performance and cannot do without using synthetic oil for lubrication. Add to these the large number of motorcycles that have been modified to increase power, as well as the growing number of commercial mods readily available for enthusiasts to increase engine power and speed, there are a lot more high-performance bikes available.

Low Powered Engines

Mineral oil is better for old motorcycles because it is thicker and doesn’t leak as easily as synthetic oil. Street bikes with engines that do not run at high rpm can also benefit as they do not require oil that can withstand very high temperatures. Scooters as well as other motorcycles that use 100 cc to 150 cc engines also run at low revolutions per minute hence mineral oil is more than adequate.

Any scooter or motorcycle that is used for commuting or delivery likely uses an engine of 50cc to 100cc that does not require much maintenance as the engine never runs at high heat or speed. These two-wheeler engines can be lubricated with standard mineral oil which is perfectly adequate for their operating temperature range.

What Is Semi-Synthetic Oil For Motorcycles?

Semi-synthetic oil is a mixture of mineral oil and synthetic oil. It comes in a ratio of 25:75 or 35:65 depending on the brand. Since both oils are homogeneous, an average user can mix them. These oils are not designed for high-performance engines but should be used in extreme cold or hot climates.

Semi-synthetic oil is manufactured from a base of highly refined mineral oil as well as many other additives. The composition of these oils is proprietary as most manufacturers prefer not to disclose their exact constituents. It is cheaper than synthetic oil but more expensive than mineral oil making it suitable for many applications that do not need an oil that can endure high temperatures.

Semi-Synthetic Oil vs Fully Synthetic Oil: Which Is Better For Motorcycles?

Semi-synthetic oil is better for motorcycles that need something better than mineral oil but don’t need the advantages that high-end synthetic oil offers. Motorcycles that are used to carrying high loads, or stop and start a lot, can benefit the most from semi-synthetic oil.

Semi-synthetic oil offers a halfway step towards using synthetic oil while cutting out the high prices. The tradeoff on cost comes with a slightly lower performance which may be perfectly acceptable for mid-range motorcycles. Since it has some of the advantages of synthetic oil, it needs to be looked at seriously as an alternative to mineral oil without the high cost.

Are The Bargain Brands Worth It?

Don’t expect bargain brands with a dubious label to perform as well as a reputable one. Synthetic oil is expensive to produce at about $20 a liter, as compared to mineral oil at $7 per liter. Your best bet is to buy from a manufacturer with a good reputation or one that has been rigorously tested.

Before making a purchase, read the label on the bottle to find out what exactly are the ratios of synthetic oil to mineral oil used. Your next best choice is to go with an oil that has been tested and not rely on the label. If you still aren’t sure what to do, then buy a reputed brand from a well-established manufacturer.

Why SAE Values Are Important

The SAE measures the oil’s viscosity as determined by the Society of Automotive Engineers. The lower the number, the better it is. SAE values are issued for the crankcase, axle, and transmission oils. Oils that flow easily through the engine while lubricating each part have the lowest SAE values. For crankcase oils, SAE ranges from 5 to 50, while axle and transmission oils range from 75 to 250.

There are 2 types of oils: multigrade and monograde. Most automotive engines use multigrade oils while much smaller engines such as lawnmowers use monograde oil. All multigrade oils must specify their low-temperature viscosity, as well as their high-temperature viscosity. This subject is too vast to go into here, nevertheless is a measure of oil quality that every user needs to be aware of.

The Viscosity Index

The viscosity index is the temperature-related change of viscosity. Any special-purpose oil that is to be used inside an internal combustion engine needs to have specific properties throughout its working temperature range. Generally, oils become thinner at high temperatures and thicker at lower temperatures.

For example, an oil’s viscosity can be completely different at 86 Fahrenheit than when it’s at 212 Fahrenheit. To ensure uniform viscosity over a wide range of temperatures, viscosity modifiers are added to the base oil in the ratio of 5% to 20%.

On the viscosity index, mineral oil ranges from 95 to 105, vegetable oil ranges from 195 to 210, and silicone oil from 205 to 400. The SAE value and the viscosity index are measures of oil quality that can help the user to decide which oil is best suited for a particular application.

Which Motorcycle Oil Is Best For You

Since mineral oil is the least expensive of these 3, its performance needs to be viewed through the lens of price before coming to any conclusion. As a cheaper alternative for low-end scooters and motorcycles, it is a feasible option when use does not justify the higher cost of synthetic oil. Motorcycles with 50 cc to 150 cc engines are very comfortable running on mineral oil.

Semi-synthetic oil is ideally used in adverse temperatures and conditions, and for mid-range motorcycles that need the increased lubrication and fluidity that it provides. The cost difference isn’t that large to warrant using mineral oil, though the engine does need the improved lubrication. Motorcycles carrying loads or running in heavy traffic for delivery purposes can benefit the most.

Semi-synthetic oils improve engine performance which can result in better fuel economy. Its lower viscosity protects the engine from friction, thereby saving on repair costs in the long run. While it may not be a big reason to switch to it, the savings in fuel and repairs do offset the increased oil price.

Fully synthetic oil is a must for high-performance engines that run at high temperatures and there cannot be any compromise on this. These engines require the highest standard of lubrication available to work optimally, which mineral oil or semi-synthetic oil cannot deliver. Even though the cost factor may be relevant, the engine requirement supersedes it.

Final Thoughts

Synthetic oil is undoubtedly the superior choice for motorcycle engine lubrication, but there are cases where mineral oil is more than enough to achieve the same end result. Given the difference in cost and benefits between oils, it is best to check which oil is most appropriate for your engine.