Use this Tyre Upsizing Fuel Efficiency Calculator to estimate how up-sizing your tyres could impact your vehicle’s mileage. Enter your original and new tyre widths (and your current mileage, if you know it) to see the estimated percentage change in fuel efficiency and what your new mileage (km/l) might be after the upgrade.
How Does Tyre Upsizing Affect Fuel Economy?
According to the SAE International Journal (2015-01-1532), “A 10% increase in tyre rolling resistance coefficient (RRC) generally results in a 1–2% decrease in fuel efficiency.” Major tyre brands like Michelin and Bridgestone also state the same. When you’re upsizing with wider or heavier tyres, there will be an increase in rolling resistance, and this added resistance results in higher fuel consumption.
In India’s stop-and-go traffic, even small changes in rolling resistance can have a big impact on how much you spend at the fuel pump.
Our calculator correlates the increase in width with the increase in rolling resistance. For every 10% increase in width, there will be an estimated 1-2% loss in mileage.
Let me explain the logic with an example. If your original tyre is 185mm wide and your new tyre is 205mm:
\[ \text{Original Tyre Width} = 185\ \text{mm} \] \[ \text{New Tyre Width} = 205\ \text{mm} \] \[ \%\ \text{Width Increase} = \frac{205 – 185}{185} \times 100 \approx 10.8\% \] \[ \text{Estimated Fuel Efficiency Drop} = 10.8\% \times 0.15 = 1.6\% \] \[ \text{Original Mileage} = 18\ \text{km/l} \] \[ \text{New Mileage} = 18 – (18 \times 0.016) = 17.7\ \text{km/l} \]If your original mileage is 18 km/l, after upsizing, you might see about 17.7 km/l.
FAQ
Does tyre upsizing always reduce fuel efficiency?
Yes, especially if you increase width or weight. If you stay within OEM-recommended sizes, the effect is small.
How much mileage drop should I expect?
A 10% wider tyre can drop mileage by 1%-2%, depending on your driving and tyre pressure.
Can I regain lost mileage after upsizing?
Yes, it’s very much possible if you’re maintaining tyre pressure, wheel alignment, and gentle driving can help you to regain the minor losses.
What are the other parameters tyre upsizing affects?
Tyre upsizing affects your vehicle’s speed, distance, ground level clearance etc. To get the exact changes in these parameters when you upsize your tyres, you can use our calculator here.