A car’s tyre contributes to almost a third of its fuel economy, with factors such as pressure, tread, alignment, and weight all playing a role in how quickly your vehicle burns propellant.
Pressure is defined as the volume of air pumped into a tyre, with the correct reading resulting in an optimal contact patch that assists in stabilising the vehicle on the road.
Meanwhile, tread refers to the grooves or patterns on tyre exteriors, which are designed to keep the wheels gripped to the road’s surface.
As per fleet management company Cartrack, ensuring that your car’s tyres are inflated to the right pressures and the tread remains healthy will go a long way to improving fuel economy.
Under and over-inflated tyres
Underinflated tyres expand the rubber’s contact patch with the road and consequently increase rolling resistance, which boosts fuel consumption as the engine must work harder to overcome the added friction.
Lower tyre pressure will also contribute to tyre bending, which can create instability when cornering at higher speeds.
The link between heightened fuel usage and overinflated tyres is similar, albeit slightly more complex.
“While tyre overinflation may not be directly related to elevated fuel consumption, it causes wear and tear over time, which increases rolling resistance,” said Cartrack.
“This results in a rise in fuel consumption, bringing about a swell in fuel economy.”
The graph below, as provided by the fleet management firm, substantiates the claim that fuel consumption falls with more inflation:
Tyre pressure is measured in bars or PSI (pounds per square inch), and the optimal reading for your car can usually be found on a small sticker in the door jamb or the user manual.
“While every vehicle has required tyre pressure, the generally recommended and accepted pressure measurement is between 28 and 36 PSI, which converts to approximately 1.9 to 2.5 bars,” said Cartrack.
“Overall, vehicle performance worsens if tyres are overinflated or underinflated, and high fuel economy is just one of the negative consequences.”
Tyre tread’s impact on fuel economy
Another important point to consider is the tread and pattern of a specific tyre you may be interested in purchasing.
The greater the tread depth, the more grip the wheel has, meaning the car exerts less energy when driving and turning. This leads to better fuel economy, and vice versa.
Additionally, tread patterns, which help with vehicle traction, have the potential to significantly influence fuel usage based on the vehicle type and conditions in which it is driving.
So-called “standard energy tyres” are what most people have on the tips of their axles, which are engineered to offer a blend of durability, comfort, and efficiency.
Ribbed tyres, on the other hand, have the lowest rolling resistance and the highest focus on frugality.
At the other end of the spectrum, aggressive tread patterns are generally designed for off-road use as they boast the highest rolling resistance and consequently the poorest economy ratings.
“Investing in energy-efficient tyres, also known as ‘eco-tyres’ or ‘green tyres’, is one great way to choose the right tyres for better fuel economy. These tyres are low-resistant,” said Cartrack.
“While they may be high-priced, the costs you will save in the long run will outweigh the initial expenses.”
Goodyear Eco Tyres
The wildcards
In addition to pressure and tread, the wheel alignment, size, and weight all impact fuel spend.
Wheel alignment can reduce or increase consumption depending on whether they’re misaligned. Misaligned wheels drag, so they use more fuel, requiring the engine to work harder.
Tyre weight affects rolling resistance, too.
The lighter the tyre, the less rolling resistance, and vice versa, thus decreasing and increasing the car’s thirst accordingly.
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