Photo: Why Drivers Overinflate Their Tires (Getty Images) Author: Konstantin Shirokun
Overinflating tires is a popular driving trick, but surprisingly, it is used for different purposes. Let's look at how overly hard tires actually affect the car's performance.
Read about the meaning of overinflated tires in the RBC-Ukraine article.
Probably every motorist knows that if you overinflate your tires by a few extra units, your car will consume less fuel. And this is not the only positive that caring motorists attribute to overinflated tires. And it is really tempting, isn't it – to reduce fuel costs by just inflating your tires? However, even if this is so, every coin has its downside.
Hard wheels – lower fuel consumption?
Experienced drivers have certainly noticed that a wheel that is less crushed in the lower part of the sidewall rolls on the road much easier. Instrumental tests confirm this, but under one condition: increasing the pressure makes sense only when it is at least 0.5 atm. Adding 0.1 – 0.2 atm reduces rolling resistance, although it does reduce it, but by a tiny amount.
What does increasing tire pressure do?
Reduced fuel consumption . The savings are small, about 1.5%. And this saving effect only applies to a certain range of average speeds, because at speeds above 80 – 90 km/h the largest share of fuel is spent on combating air resistance, not rolling;
Improving the car's dynamics. Lower rolling resistance, of course, improves the car's acceleration. However, as in the first point, the percentage of increase in dynamics is small and borders on the measurement error;
The best protection for the tire and disk. The risk of cutting the tire and bending the wheel disk on bumps will be less. If the tire is harder, it will be less crushed when hitting uneven surfaces, therefore, if the tire is crushed, the wheel disk will not reach the asphalt and the sidewall of the tire will not be cut.
Disadvantages of Overinflated Tires
There are no improvements without drawbacks, especially if the tuning is not approved by the car manufacturer.
Deterioration of comfort . Naturally, a harder wheel absorbs less shocks and vibrations from the road and transmits them to the body better. Additional shaking accompanies any experiments with air pressure in the tires – at least when it is exceeded by half an atmosphere or more.
Reduced durability of the chassis. Designers calculate the characteristics of the suspension and steering for a certain wheel rigidity. Consequently, on tires that are too rigid, all the jolts, impacts and vibrations from the road are transmitted to the chassis parts. And it is not surprising that they wear out prematurely. We are talking primarily about hub bearings, ball joints, stabilizer struts, steering trapezoid joints, silent blocks, lever bushings. Of course, detailed calculations can be organized, but it is very likely that replacing chassis parts will cost more than the above-mentioned 1.5 percent of saved fuel.
The tire wears out faster. Abnormal tire pressure distorts the contact patch of the wheel with the road. That is, each wheel will rest on the road through a reduced area of the tread, and therefore this tread will wear out faster and unevenly, with a “bald” area in the center of the tread track.
Worse control. Since the said contact patch of the tread with the road will not be as (in fact, smaller) as programmed by the designers, the car will not be controlled as it should be. That is, on an over-inflated tire, the car is worse controlled and does not hold the set course as reliably. The braking distance will be longer, especially in rainy weather.
Short
Although the positive effect of increased tire pressure is small, it exists. And if your car is used in conditions where those advantages matter, it makes sense to use the specified method. Not forgetting about the negative effects, or rather, about their correction during movement – by increased accuracy when driving.
Materials from Rosava and Nokian Tyres were used in preparing this article .
Let us recall that RBC-Ukraine recently reported why pedestrians are not always right.