Many people wonder about does tire size affect gas mileage. In short, I would like to say “Yes”. Tire size is really important for better fuel economy. It is always good to use the tire size that is recommended by the vehicle manufacturer. You can find the tire size on the vehicle manual, more here.
What Happens When We Use Larger Tire Size in a Vehicle?
Larger tire contains more weight. So, if you use a tire that is larger than the recommended size, it will do nothing but increase the weight of your vehicle and the engine has to do more work to push the vehicle forward. More engine work means more fuel consumption.
However, the fuel consumption is not very significant and you may not be able to notice it in a week. But, if you make a fuel log book you will find the difference.
What Happens When We Use Smaller Tire Size in a Vehicle?
Smaller tire size is also responsible for extra fuel consumption. If the tire size is smaller it needs to spin faster for going forward. The RPM of the engine needs to stay high to run at higher speed if the tire size is smaller than recommended. So, it’s important to use the optimally sized tire.
If you are off-roader it may sometimes good to use larger tires because it will help you to get more grips and ground clearance in different situations as we don’t think about fuel consumption when off-road driving.
Another exception is driving on the highway. If you drive frequently on highway or freeways with a speed of above 65km/h in that case, you may use one or two sizes larger tire for better mileage. Here, the engine needs to push the vehicle at the beginning but later when you drive at a constant speed it will have to do less work and can save fuel.
Other Factors than Tire Size
However, often you may get better performance from a larger sized tire if the grip is higher than the recommended sized tire. This is because the friction between the tire and road plays important role in fuel consumption. The lower the friction is, the better the mileage will be. But, the grip is also important for safe driving during rainy days.
Tire air pressure is another important factor that you must maintain regularly. Under or over inflated tire will reduce the mileage of your car. It’s all about basic physics, so, it is always good to do what the manufacturer suggested in the manual.
Fuel consumption of the vehicle and longevity of the tire depends completely on how you are dealing with the tire size and air pressure. We often try to override what is recommended by the manufacturer but it hardly gives any better result.