Fuel Economy 60 vs. 70 mph – Which is More Efficient?

Drivers take on different speeds depending on the road they’re driving or their destination. Usually, the faster you go, the quicker you get to your destination.

However, whatever your reasons are, understand that your speed impacts how much fuel your car uses, which invariably affects your wallet.

While 60mph is mostly recommended, many drivers also take on 70mph while on the wheel, both of which are still fuel efficient. So in this article, I will walk you through fuel economy 60 vs. 70 mph to see which is more efficient or will benefit your pocket.

what speed maximize fuel economy

Fuel Economy 60 vs. 70 mph Explained.

Most car manufacturers recommend driving at most 60 mph to save fuel. This is recommended because 60 mph is the allowed speed on most highways. Hence, a reason manufacturers set 60 mph as the most economical mode.

However, the 60 mph doesn’t work across all cars, especially those with smaller engines and displacement. For example, small vehicles with a 3-cylinder engine and displacement of about 1 liter will usually need more rotation to push. So for such vehicles, their required speed might go up to 70 mph.

But one thing is clear. The lower your speed, the better fuel economy you get. This also implies that driving faster or past your optimal speed limit causes you to use more fuel. For example, according to the Department of Transport, one can have a 9% decrease in fuel efficiency when driving at 70 mph compared to driving at  60 mph, regardless of your car’s economic speed limit. 

This means that even if your car’s speed limit or the most economical mode is 70 mph, drivers who drive at 60 mph, regardless of their economical mode, will save more fuel than you. The only concern will be if those driving at 60 mph also save gas based on their manufacturer-recommended speed.

However, while slower driving boosts fuel economy, it isn’t always the case with all cars, like the example I gave in the 70 mph situation above. This is true because while 60mph may be economical in many vehicles, 70 mph may also be economical in certain vehicles. Therefore the most important thing is what your car’s most economical speed is. While some are set at the highest, 60 mph, others can go up to 70 mph.

What is the fuel efficiency of 70 mph?

Driving at 70 mph can let you cover up to 36.1 mpg. Meaning driving at a speed of 70 miles per hour can allow you to go a distance of 36.1 miles with just one gallon of fuel. While this is lower compared to 50mph, which allows you to cover 47.6 miles per gallon, it’s better when compared to higher speeds, like 80 or even 90 mph.

For example, driving at 80 mph instead of 70 mph can cost you about 25% more fuel. Apparently, while operating at the recommended speed limit keeps you safe, it also saves you fuel by 25 %, invariably helping your pocket.

Best speed for fuel economy

The best speed for fuel economy, whether in Kmh or mph, is driving at your vehicle’s lowest speed and the highest gear. So what’s the lowest or recommended speed for your vehicle? Some vehicles’ optimal speed is within 40-75mph.

While most smaller cars suggest 40-50 mph, vehicles with bigger engines might recommend 55-75 mph. Others, like the 4-cylinder engines, recommend between 45-65 mph, while others with six cylinders and above between 50-70 mph. So it typically depends on your vehicle.

However, for most cars, the optimal speed is around 60 mph since that is recommended for highway driving. However, while the optimal highway rate is 60 mph, that may not be your car’s lowest gear. So if you want better gas mileage, drive at your vehicle’s lowest speed and highest gear.

For example, if your speed limit is 40-50 mph, 40 mph will be the best speed for fuel economy for your specific vehicle. And more importantly, ensure this speed is consistent. Don’t drive at 40 or 50 mph this minute and 60 mph the next minute, and expect to get consistent fuel economy. The change in speed will also change how much fuel you save.

For example, driving at 60mph instead of 50 mph can cost you 9% more fuel. In the same vein, cruising at 55 mph instead of 65 mph can enhance fuel economy by up to 9%. The inconsistencies in speed adjustments will impact fuel economy.

More like you lose what you gain this minute and gain what you lose the other minute, a reason I hit on the keyword—consistency. Moreso, match your fuel consumption vs speed calculator. Your speed calculator will quickly relate how much fuel is used up since your speed influences your fuel consumption.

Also, note that these percentage gains or losses in fuel efficiency when cruising at a certain speed may differ from one vehicle to another depending on several factors. These include car size, engine type, transmission, drivetrain, etc. 

A big car with a higher speed transmission and a bigger engine with 4wd may consume more fuel than a smaller car with the same features driving at the same mph. That said, while driving at your vehicle’s lowest speed and highest gear can help boost fuel economy, speed isn’t the only thing that impacts fuel consumption. Other ways to save fuel

The following are things to put into perspective if you really want to save fuel.

The right tire pressure

Ensure your tires are at the correct or manufacturer-recommended pressure. Rolling resistance increases if tires are underinflated, invariably causing the tires to have a hard time moving and therefore need more fuel. Overinflated tires may also lead to premature tire wear and invariably poor handling.

Avoid aggressive driving

Avoid braking, accelerating, or speeding too much. You will consume more fuel doing any of these. Accelerating slowly and avoiding sudden stop-and-start situations will significantly boost your vehicle’s fuel efficiency.

Make use of cruise control.

I stated above that one way to save fuel is by driving consistently at your car’s least speed. Cruise control allows you to stay at a particular speed, invariably avoiding speed fluctuations that might impact fuel economy.

This is especially useful on highways when speed change isn’t needed. If, however, you drive through start and stop traffic and hilly or windy terrains, avoid cruise control since you would need to adjust speeds in these conditions.

So technically, it’s more efficient to drive on highways since you won’t need to adjust speeds too often. And even if your legs are tired, cruise control will keep you at that speed for as long as you drive. If you’re asking, is it more fuel efficient to drive on the highway? Now you know.

Avoid too much load.

The lighter your vehicle, the easier it moves; hence, it consumes less fuel. To shed more weight, try removing any object that might not be useful while driving. This could be extra cloth or sports wear or any heavy tools not needed. You can even remove the roof rack.

Use the correct motor oil.

Every car has the manufacturer-recommended engine oil, as stated in the manual. Using the right oil will usually reduce friction and invariably boosts fuel economy.

Avoid leaving cars idle for long.

At idle, your car burns fuel since the engine is on. So you might want to stop leaving your car idle for extended periods if you want better fuel efficiency. If you’re not ready to drive, turn off the engine. Good examples of such situations are when you’re stuck in traffic or waiting for someone. 

More so, don’t leave your car idle when loaded with goods. If only running the engine can cause your fuel consumption, imagine adding load. But how much fuel does a good vehicle consume when left idling? It typically depends on the weight of the goods.

Make proper plans

Don’t drive when it’s not necessary; this reduces the number of miles you cover, invariably saving fuel. For travelers, ensure you plan and take the most efficient routes that won’t keep you on the road for long.

Turning on your AC also puts more load on the engine, resulting in more fuel consumption. So you may want to turn off the AC, especially on cold days. Only put it on when necessary.

Buy quality fuel

Bad or low-quality fuel houses contaminants that can clog the fuel injector and other fuel delivery systems, restricting fuel flow and invariably affecting fuel mileage. So you might want to invest in only good quality fuel.

Don’t exceed your car’s speed limit.

Even if you are not driving at your car’s least speed, don’t exceed the recommended speed limit. Moving faster than recommended causes your vehicle to deal with more wind resistance. This invariably causes your car to need more power to keep on with the speed, causing more fuel consumption.

To avoid this, drive consistently within the speed limit of your car. You can even use your cruise control to ensure you constantly stay at that speed. The relationship between fuel consumption vs. speed formula is a serious one.

Maintenance is key

Proper maintenance keeps your car in good working condition, reduces emissions, and invariably boosts fuel economy. So ensure you follow your car manufacturer’s recommendations in doing maintenance.

Final Words

So comparing fuel economy 60 vs. 70 mpg, which is better? Generally, the higher your speed, the more fuel you consume, hence the need to go slower. While 60 mph is more efficient, your vehicle speed limit matters. For example, while 60 mph is excellent for some cars, less or more mph is also fuel efficient for others. So the best is to wage on your car’s most economical speed limit.

In fact, if you are keen on saving gas, drive consistently on your car’s least speed limit, together with the highest gear. It’s also worth noting that your car’s speed can’t do the magic alone. So also implement other things highlighted above if you truly want to save fuel.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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