When you stop at a service station to fill up your tank, you'll likely notice premium and unleaded gas available at the pumps. You may wonder about the differences between these fuel types and which one your vehicle requires. Here's what to know about these two grades and how to decide between them.

Unleaded

The primary difference between premium and unleaded gas is that the latter has a lower octane rating of 87. The octane number measures the fuel's ability to withstand compression within an engine without prematurely combusting, which produces an obtrusive knocking or rattling sound when it occurs. This can also put pressure and stress on the engine components, leading to damages and breakdowns. 

Most vehicles, especially modern cars and trucks, take unleaded gas because the engines in standard sedans, trucks, and SUVs do not produce enough power to make premature combustion and knocking a risk. However, you can double-check your manufacturer-recommended gasoline grade by looking in your owner's manual or on the gas cap. 

Premium

Premium gas has a higher octane rating of 91 to 94, making it more resistant to pre-ignition and knocking. Since older automobiles typically have more wear and tear on the engine, knocking may damage weakened internal components such as rods, pistons, and valves. Manufacturers recommend using premium gasoline to protect the engines in older vehicles and prolong their life span. 

Additionally, modern cars and trucks with high-powered turbo engines produce more heat and use a higher compression ratio, causing them to combust unleaded fuel more rapidly. Since this can make obnoxious sounds and cause damage to engines, you should use premium fuel in these cars and trucks as a safeguard against pre-ignition.

Though premium fuel often has a higher price, it can save money in the long term by preventing costly engine repairs or rebuilds. At the same time, using premium fuel in vehicles that don't require it might not cause any harm, but it likely won't offer any significant advantages.

Whether you need to fill up your tank with premium or unleaded gas, stop at Tri-Mart BP. This gas station, truck stop, and convenience store offers fuel along with snacks and drinks to drivers in Tripoli, WI. Call (715) 564-2440 to ask about available gasoline grades and visit the website to learn more about how they can keep you on the roads.