Even if you don't know much about cars, you likely know that tires are an important component when it comes to a vehicle's overall operation and performance. And perhaps you've heard that tire size can affect fuel economy. So, do they? We did the research to bring you the answer.
The bigger the tires, the worse the fuel economy, and vice versa. Bigger tires are heavier than smaller tires, and, similarly, they have greater rolling resistance than smaller tires. Both of these things mean more engine power is required to move them, and the harder the engine has to work, the more fuel it has to burn.
Wider tires will also have greater rolling resistance and thus decreased fuel economy. However, wider tires can better grip the road in certain conditions, which provides enhanced handling and safety benefits.
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If you still have some more questions about how tire size and width affect fuel economy and the overall driving experience, don't worry. In this post, we'll discuss the topic in more detail. We'll also talk about what type of tire yields the best fuel economy, the benefits and drawbacks of wide vs. narrow tires, and more. Without further ado, let's get into it.
How Much Does Tire Size Affect MPG?
To better understand how tire size affects fuel economy, we'll talk about two factors—weight and rolling resistance.
It's hard to say exactly how much tire size affects fuel economy; fuel economy is already determined by several dynamic factors. However, it's safe to say that the larger the tires, the worse the fuel economy. And on the other hand, the smaller the tires, the better the fuel economy.
Larger tires are made up of more material than smaller tires—the rubber, pile layers, and metal cords. The more material there is, the heavier the tire will be. This increase in weight means the engine has to work harder to move the tires. And the harder the engine has to work, the less fuel efficient it will be.
The larger the tire, the greater the amount of tread that will be in contact with the road. This means larger tires will have greater rolling resistance than smaller tires. Rolling resistance is exactly what it sounds like—an object's ability to resist being rolled.
Since larger tires have more tread contacting the surface of the road, there will be more friction between the rubber and the road. This friction will make it more difficult for the engine to move the tire.
And it's important to note that tires resist being rolled at all times while driving. In other words, this isn't just a factor at play when accelerating. At all times while the vehicle is in motion, the engine has to work harder than it otherwise would with tires that have more rolling resistance.
However, it's worth noting that there are several other factors that affect a tire's rolling resistance in addition to its size.
The condition of the road's surface, the amount of drag on the tires (which is a result of how fast the vehicle is traveling), and the level of inflation (more on this later) are all factors that determine how much engine power is required to move the tires.
What Type Of Tire Gives The Best Fuel Mileage?
If you're in the market for new tires and are looking for the most fuel-efficient option, you'll want to look at a set of normal street tires. If you drive a smaller car like a sedan or coupe, you really don't have an option; since your vehicle is designed exclusively for commuting, the tires manufactured for it will reflect that.
But if you drive an SUV or pickup truck, you have more options to sort through. Off-road or all-terrain tires are common options for these vehicles, but while these tires may look cool, they aren't engineered to maximize fuel economy. The tread on these tires facilitates off-road driving; they aren't optimal for commuting.
So, if fuel economy is your top priority, choose a good set of street tires. Given the sheer number of available tires, your best bet is to go to a reputable tire dealer (such as Discount Tire) and speak with a tire professional.
Are Wider Tires Better?
Now that we've talked about tire size in general, we'll discuss the relevance of a tire's width. When it comes to different environmental conditions, the relationship between tire width and performance is a bit complicated.
Wider tires are a better choice for dry conditions. On dry surfaces, wider tires can improve overall performance. In these conditions, wider tires can improve maneuverability/handling.
However, narrower tires are preferred in snowy/icy winter conditions. The narrower the tire, the greater the pressure exerted on the ground under the tire. When the road is snowy or icy, this can result in superior handling characteristics.
Are Wider Tires Better In The Rain?
But things get complicated in wet conditions. When driving on roads that are simply wet (i.e. not through puddles), the sipes—the grooves and channels—of a tire help move water away, improving traction. And wider tires have more sipes than narrower tires, which makes them the superior choice here.
However, narrower tires have the upper hand when it comes to driving through standing water. As mentioned earlier, narrower tires exert more concentrated downward pressure, a characteristic that proves beneficial when driving through puddles.
Due to this concentrated pressure, narrower tires can more easily split standing water. Since wider tires can't do this as effectively, they are more susceptible to hydroplaning.
How Can You Improve Gas Mileage?
Now that we've discussed tires at length, we'll talk about some general pointers for improving fuel economy.
Ensure Tires Are Properly Inflated
Proper tire inflation is key when it comes to fuel economy. Underinflation is often the culprit behind small decreases in fuel economy. When tires are underinflated, more of the tire contacts the road. This increases the friction and the rolling resistance, which in turn requires more engine power.
Accelerate More Slowly
Another easy way to improve your vehicle's fuel economy is to get in the habit of accelerating more slowly. Generally speaking, the engine is under the most strain when accelerating from a stop; this is why a vehicle's fuel economy figures are typically worse in the city as opposed to the highway.
The next time you drive, try making slow, conservative accelerations, and take note of the engine RPMs throughout the acceleration. Then, use this figure as a maximum engine RPM limit reference going forward.
Drive The Speed Limit
Another way to improve fuel economy is to simply drive the speed limit as opposed to exceeding it. In general, when you drive more slowly, less fuel is required. So, rather than exceed the speed limit by 5 MPH all the time (as most people tend to do), drive the speed limit and conserve fuel.
Remove Excess Weight From Vehicle
When your vehicle is heavier, more engine power will always be required to move it. Do a thorough inspection of your vehicle's cabin/trunk/bed, and remove any unnecessary items. Although seemingly insignificant, small amounts of weight can have a substantial impact on fuel consumption over time.
Perform Proper Routine Maintenance
Routine maintenance is key when it comes to optimizing fuel economy. Maintenance items like spark plug changes, air filter changes, and oil/filter changes should be completed on time to keep your vehicle in tip-top operating shape. The better your vehicle runs, the less fuel it will consume.
Keep Tires Rotated And Balanced And Wheels Aligned
Be sure to rotate and balance your tires according to your manufacturer's recommended maintenance schedule, and have the wheels aligned at the first sign of misalignment. Doing these things will minimize undue friction that can result from unbalanced tires and poorly aligned wheels.
Read more about tire alignments here: Do I Need An Alignment After Replacing Rear Tires?
We hope this guide has helped you understand how tire size and width affect your driving experience. Remember, tires are arguably the most important factor when it comes to your vehicle's safety and overall performance.
Before you go, be sure to take a look at these other guides:
Gas Mileage Dropped After Getting New Tires – What To Do?