“Kitna deti hai?” is a question that is bound to come up if you are discussing cars in India. And it’s not out of frugality. Rather, the question reflects our fundamental desire to get the best possible return on an investment. Which also means that some of us are constantly trying to push the limits of fuel efficiency by optimizing speeds, switching engine fluids, and other such methods.

But did you know? Tyres, often relegated to the background of a car's mechanics, also play a surprisingly significant role in fuel efficiency.

In today’s post, we are discussing just that.
 

Tyre Rolling Resistance and Fuel-Efficiency

At the heart of the tyre's influence on fuel efficiency lies rolling resistance.

Typically a vehicle converts thermal energy into kinetic energy, depending on the friction between the tyre and road surface to move forward and backward. Rolling resistance is the amount of friction required to move the tyre and the vehicle. Different tyres exhibit varying degrees of rolling resistance, directly affecting the power required from the engine to propel the vehicle.

Tyres with lower rolling resistance will need less energy to move, and thus offer better fuel economy.
 

Factors That Increase or Decrease Rolling Resistance

In context of car and SUV, there are several factors contributing to the rolling resistance equation of tyres:

Tread Pattern

Smoother tread patterns that lack grooves and sipes, like the ones found on F1 race cars have the lowest rolling resistance, whereas tyres with big and blocky grooves, like the ones seen on off-road vehicles, will have the highest level of rolling resistance. However, these are extreme examples.

A regular daily-driver car needs tyres with a balanced rolling resistance coefficient. That’s where advanced tread patterns like the Apollo Amazer 4G shine, offering sure footed control of your vehicle while also ensuring minimal thermal loss when moving the car.

Tyre Width

You may have often heard that fuel efficiency drops after installing bulkier tyres on a car or bike. It’s because tyre width plays a role in increasing or decreasing a tyre’s rolling resistance.

Wider tyres are heavier to move and will have a bigger contact patch with the road surface, resulting in more friction and energy expenditure. On the other hand, thinner tyres are lighter and have smaller contact patches, resulting in less friction and energy loss. But both approaches have their advantages and pitfalls.

Wider tyres improve handling and stability at the cost of fuel efficiency while thinner tyres improve fuel economy but compromise ride quality and safety. Once again a balanced approach is needed to obtain ideal rolling resistance.

Carmakers generally optimize their models for cost, which is why you see different tyre and rim sizes on different variants of the same car. Our recommendation is to check your vehicle’s manual for recommended tyre sizes and upsize or downsize accordingly. Or you can always get the best advice at an Apollo tyres shop near you.

Tyre Pressure

One of the universal tips for maintaining tyre health is to simply keep tabs on your tyre pressure. Under-inflated tyres increase the contact patch with the road, leading to significantly higher rolling resistance. Over-inflated tyres, while reducing contact patch, often increase deformation and resistance at the tyre/road interface. The optimal pressure, typically indicated in the vehicle's owner's manual, strikes a balance between rolling resistance and handling.

Tyre Construction

The internal structure of the tyre, including the number of ply layers and the type of cord used, plays a role in rolling resistance. Modern radial tyres, like the Apollo Alnac 4G for cars and Apollo Tramplr series for motorcycles, feature a more sophisticated construction that enhances fuel efficiency compared to older, bias-ply tyres.

Manufacturers often use fuel efficiency rating labels to provide consumers with a comparison between tyres. These ratings often consider rolling resistance, but the metrics are often limited, and it is important to look beyond these labels to fully understand the tyre’s impact on fuel efficiency.
 

Other Tyre Related Factors That Affect Fuel Efficiency

While rolling resistance is central to the issue, there are other tyre-related aspects which can also affect fuel economy, such as:

• Rim and Tyre Shape: The shape of a tyre can influence the overall vehicle's aerodynamics. Tyres that generate more drag, particularly at higher speeds, result in increased fuel consumption. That’s why we are witnessing more aerodynamic rim designs and tyre shapes, particularly now with the rising popularity of electric cars which depend heavily on airflow around the car to increase driving range.
• Load Capacity: Overloading a vehicle invariably increases the tyre rolling resistance, as there is greater weight on the tyres. The larger weight causes a wider contact patch between the tyre and the road surface, thus increasing friction and the rolling resistance coefficient.
• Tread Wear: As a tyre wears down, the tread pattern and rubber compound can degrade. This can increase rolling resistance over time, especially in case of uneven wear, eventually impacting fuel efficiency. Therefore, regular tread checks and replacements are crucial for maintaining optimum fuel economy.
   

Tips for Improving Fuel Efficiency Through Proper Tyre Care

Lastly, a few expert tips for maintaining your car tyres for optimal rolling resistance and fuel efficiency:

• Ensuring optimal tyre pressure is a simple but crucial step towards achieving better fuel efficiency. Regular checks, using a reliable tyre pressure gauge can make an immediate difference to your fuel economy figures.
• Choosing tyres that are specifically designed for fuel efficiency is another way to improve performance per liter. Go the distance with tyre brands and models that are known for their low rolling resistance characteristics, like the Apollo Amazer XP.
• Consider the impact of passenger and cargo load when assessing overall tyre needs. Heavier loads require tyres capable of sustaining the weight without compromising fuel efficiency.
• Regular tyre maintenance, including tread checks, rotations, and replacements as needed, is paramount for maintaining optimal fuel economy. A worn-out tyre will negatively affect rolling resistance and handling, ultimately increasing fuel consumption.

Tyres are not merely components that connect a car to the road; they significantly influence fuel efficiency. Understanding the connection between tyre characteristics, rolling resistance, and vehicle performance empowers drivers to make informed choices that can translate to lower fuel bills and a more sustainable driving experience. For more such tips, continue following our blog and subscribe to Apollo Tyres handles on Facebook, Instagram, X and YouTube.