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How to Improve Your Car’s Mileage with the Right Tyre Size?

Tyres affect the vehicle’s performance on multiple levels. If it’s bigger than the factory-fitting size, it will have bad effects on the cabin noise level and fuel usage. Whereas, a size smaller than the required standard will be dangerous and will lead to under-usage of the car’s features.

Think of it like this – wearing a shoe bigger than your foot size will need extra strength from you to hold on to it and its weight. On the other hand, (or rather foot), a size smaller than your foot will be awkward and damage your stance. The answer is rather easy. Just go for the right size. Let’s understand how the right-size tyre can increase your car’s efficiency and add to its mileage.

Tyre Size & Fuel Economy

Understanding the link between tyre size and fuel economy includes two key concepts: wind resistance and rolling resistance.

At higher speeds, a car experiences increased air resistance, requiring more effort to move through the air. This resistance leads to greater fuel usage and lower fuel economy. The size of your tyres plays a part in determining the amount of wind resistance your car feels.

On the other hand, rolling resistance is the force that fights the action of a tyre as it rolls along the road. The larger the tyre, the more energy is needed to beat this resistance, which can lead to lower fuel economy.

However, it’s important to remember that not all tyres are made equal when it comes to rolling resistance. Some tyre makers have created special shapes and materials that decrease rolling resistance, resulting in better fuel economy.

Fuel and Tyre Treads

The wear on your tyres can also impact your vehicle’s fuel efficiency. Race car drivers utilize tyres with no tread for a reason. They provide less resistance and make it easy for their cars to hit faster speeds. Unlike racing car drivers, however, we need to tread on our vehicles in order for our vehicles to successfully stop in harsh weather. If you have big off-road tyres but don’t go off-road on a daily basis, you might be losing a lot of gas. The idea is to get street tyres for your car so that it doesn’t have to do as much work.

The type of tyre you choose for your car can also impact your MPG. Smaller tyres lower fuel consumption while bigger tyres increase fuel consumption.

It is important to recalibrate your speedometer if you make any changes to your tyres, such as increasing the tyre or wheel size. If the new tyres are wider than the original ones, it will cause an increase in gas usage and your speedometer will show a slower reading than your actual speed. Conversely, if the new tyres are smaller than the original ones, it will have the opposite effect. These changes will also have an impact on your overall fuel economy, which should be taken into consideration when making any alterations to your wheels or tyres.

If you choose to change your wheels to a bigger size, a way to adjust for this change in speed control and fuel usage, is to choose a tyre with a similarly lower sidewall to the increase in wheel size. An example would be if you increase your wheel by one inch overall then your tyres should decrease by close to one inch overall to keep this careful balance.

Read More: Everything You Need To Know About Tyre Tread

Tyre types and their effects:

Tyre sizes can vary significantly; some tyres are wide, others are narrow, and they may have larger rims or taller sidewalls. So, let’s dive deeper into this.

Wide tyres:

Wide tyres mean a bigger area which means more touch with the surface resulting in better grip and increased friction. If you are a person who loves driving, you are going to enjoy this as its grip will help you to accelerate or stop faster. Well, a better grip means more power would be needed to beat the friction resulting in lower fuel economy.

Large Outer Diameter:

Wider tyres look good, but they don’t always improve your car’s fuel economy. Generally, when people install new tyres with bigger outer diameter, the width of the tyre is also raised. Fuel economy is reduced when width increases due to increased friction.

Discussing tyres of the same width but varying diameters, the larger diameter tyre can enhance your vehicle’s fuel economy. This is because a larger diameter means the wheel rotates fewer times to cover the same distance, resulting in lower RPM and improved fuel efficiency.

Read More: Benefits of Car Tyres Based On Their Multiple Types

Small Outer Diameter:

When compared to larger tyres, small tyres are more fuel efficient if you are doing a lot of starting and stopping i.e., if you drive in a city with a lot of traffic smaller tyres are ideal as it takes extra power to fight friction due to larger tyres.

If you are a person who goes long routes with constant speeds, then not only do larger tyres help increase fuel economy, but they also reduce noise and make the ride comfy.

If you have a vehicle and you are going to change its wheel size, keep in mind that the tyres given to the car are the most efficient ones and changing its size may cause the performance to differ. However, if you’re only altering the size of your rims without modifying the outer diameter or width, it won’t significantly impact the car’s fuel efficiency.

Check your tyre pressure

Since tyres naturally lose air at a rate of up to 2 PSI per month, regularly checking your tyre pressure can help maximize your fuel efficiency. Ensuring the air in your tyres is topped up not only prolongs the life of the tread but also improves fuel economy – as there is less moving resistance with the road.

If your tyres are even slightly distorted due to incorrect tyre pressure, you’ll be using more fuel to keep your car moving smoothly. This is because of the extra pressure while driving that comes from an uneven tyre. You can use a tyre pressure tool to check the appropriate tyre pressure for your car.

Always choose the right tyres

Many believe that all tyres are identical, but this is not the case. The incorrect tyres can impair your car’s performance and its capacity to tackle harsh weather conditions. Tyres are mainly categorized into summer, winter, and all-season types. Unless you experience very cold weather, all-season tyres, which are the most cost-effective, are recommended. For specific weather and climate challenges, specialized tyres are available. Additionally, there are tyres designed for speed or fuel efficiency, allowing you to select based on your requirements.


Do Wider Tyres Affect Fuel Economy?

Wider tyres do impact fuel economy badly for two key reasons. Firstly, they raise the vehicle’s weight, similar to bigger diameter tyres. Secondly, bigger tyres create more rolling resistance because of the greater surface area of the tread touching the road. This greater resistance demands more fuel to spin the tyres, eventually lowering total fuel economy.

What is the influence of Tyre Weight and Tread Design ?

The weight of tyres impacts fuel economy, with larger tyres taking more fuel due to greater car mass. Additionally, the tyre design affects fuel economy, as more sharp treads create greater moving resistance, leading to decreased MPG. Under-inflated tyres worsen this problem by increasing the touch area between the tread and the road surface.

Is there a formula or calculator for determining MPG with different tyre sizes?

There isn’t a general method for estimating exact changes in fuel economy when moving tyre sizes due to the numerous factors involved. Attempting to determine based on tyre diameter and maker specs doesn’t give useful real-world data. It’s more realistic to compare actual fuel usage before and after changing tyre sizes to properly gauge the effect on miles.

How to Manually Determine Your Actual Miles Per Gallon
To directly find your real miles per gallon (MPG), follow these steps:

  • Fill your vehicle’s fuel tank fully.
  • Drive a set distance, keeping track of the miles.
  • Refill the tank at a gas station and note the number of gallons needed to top it off.
  • Divide the total miles driven by the gallons of gas used.
  • This calculation gives an estimated MPG standard.

Will Changing Tyre Sizes Affect Anything Else?

Changing tyre sizes can impact various measures and factors beyond just a vehicle’s fuel economy. Larger or smaller diameter tyres can affect revolutions per minute (RPM) and, consequently, speedometer and odometer numbers. Larger tyres may cause the speedometer to mark a slower speed and the odometer to record fewer miles, while smaller tyres can result in a higher speedometer reading and a greater odometer range.

How to Optimize Tyre Setup for MPG ?
To maximize your tyre setting for the best fuel economy:

  1. 1. Choose the smallest wheels and tyres made for your car.
  2. 2. Look for tyres with low rolling resistance to reduce fuel usage.
  3. 3. Ensure your vehicle’s tyres are properly filled to reduce needless fuel usage.

Do Aftermarket Wheels Affect Gas Mileage?

The addition of custom wheels can cause a vehicle’s gas economy to suffer, under certain conditions. This is the case whenever a set of custom wheels is exceedingly heavier than those of a stock design or are of a shape that necessitates the use of tyres that are of a greater width and/or thickness.

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