Why fill your tires with nitrogen?

Injecting nitrogen into tires – are there any real benefits?

In recent years, tire shops have been trying to popularize a new service - filling car tires with nitrogen instead of regular air. This topic is overgrown with many fables and myths, as sellers endow “nitrogen” rays with fictitious advantages, and opponents put forward theories that have not been tested in practice. Why inflate wheels with pure nitrogen and what real benefits the driver receives, read in this publication.

Gas injection technology

From a school physics course we know that the surrounding air already contains 78% nitrogen (meaning volume fractions). The remaining 22% is distributed between oxygen (almost 21%) and a good dozen different gases, whose share is about 1%. Also, water vapor is dissolved in the air, amounting to 0.2 to 2.5% of the volume of gases. This value varies depending on the weather, season and latitude.

The essence of the technology is simple: extract 78% of the gas from the air and fill car cylinders. In practice, nitrogen is pumped into tires as follows:

1. The wheel valve is connected by a hose to an automatic vacuum-nitrogen installation.
2. After switching on, the unit completely sucks out the air mixture from the tire.
3. Having passed it through a system of special filters and a dryer, the installation produces nitrogen with a purity of at least 95%.
4. The purified gas is pumped into the wheel in compliance with the pressure required by the manufacturer.

By treating ordinary air, a nitrogen generator not only removes oxygen and other impurities, but also traps water vapor. This fact should be taken into account in further consideration of the issue in order to separate the real pros and cons of the procedure from myths.

Reference. Technical specialists serving Formula 1 races and various rallies do not face such a question. The slopes of all cars are filled with nitrogen by default.

Real and imagined benefits

To begin with, it’s worth listing all the advantages indicated on billboards near tire shops. What does the use of nitrogen in car cylinders provide, according to the service sellers:

• constant tire pressure regardless of ambient temperature and road surface;
• improved road grip and slower tread wear;
• the ride of the car becomes softer;
• tires do not go flat over time;
• reduction of braking distance and improvement of acceleration dynamics;
• the likelihood of tires exploding under load is noticeably reduced.

Next, it is proposed to analyze each point separately and determine the reliability of these statements, based on practical observations.

When the rubber heats up, the pressure does not increase

All drivers who pump their own tires know about the effect of thermal expansion of air in tires. The bottom line is this: when it warms up outside, the gas in the cylinders expands and the pressure in the wheels increases by 0.2–0.5 bar. And vice versa, after the onset of cold weather, the stingrays “sag.” Advertising claims: the coefficient of thermal expansion of nitrogen is 7 times less, so the tire pressure practically does not change.

Opponents of this theory rely on the laws of physics, according to which all gases expand equally. That is, the pressure difference in wheels inflated with nitrogen and an air mixture is negligible.

In practice, the situation is different: inflating tires with nitrogen actually allows you to keep the pressure at the same level regardless of the outside temperature. Probably, the presence of water vapor in the air, which is absent in a nitrogen environment, plays a role here (remember, the gas is dried before injection).

Improving the performance properties of rubber

The adhesion of the working surface of the wheel to the road surface depends on many factors, including:

• rubber properties, product quality;
• shape, pattern and design of the tread;
• the size of the contact patch and the distribution of forces in it;
• type and condition of the road surface.

The type of gas pumped into the tire does not have any effect on traction or tread wear. You can artificially change the pressure in the slopes and in this way increase or decrease the contact patch, but the contents of the cylinder do not matter. The statement is not true.

Smooth car ride

Another answer to the question why fill tires with nitrogen is as follows: a cylinder inflated with this gas is not as elastic as an air cylinder. As a result, the wheel bounces less off road unevenness, the ride becomes more comfortable, and the suspension lasts longer.

The argument is explained by the lower specific gravity of nitrogen compared to air, although in reality the difference is small. There is an interesting point here: the specific gravity of the air mixture is a variable value, depending on temperature and moisture content. If you pump in cold air at minus 20 °C, then the weight of 1 m 3 is 1.396 kg, warm air (+10 °C) is 1.248 kg.

Practical observations have shown that a softer ride is felt when driving over small bumps on cars in the budget price category with a classic suspension. In business and premium class cars, the improvement in comfort is not felt, since they use an effective multi-link suspension.

The ramps don't come down

The advertisement says: a nitrogen molecule is larger than an air particle, so it does not “crawl” into the microcracks in rubber that inevitably form as a result of use on uneven roads. Therefore, the tires do not go flat for a long time and do not require inflation.

The statement falls into the category of absurd. The difference between air and nitrogen particles is so tiny (0.02 nanometers) that if a crack occurs, molecules of both gases will freely penetrate it. What happens in practice: over the same period of time, an “air” wheel loses 0.5 Bar, while a nitrogen-filled wheel loses 0.47 Bar.

Improved ride quality and safety

When tires are inflated with nitrogen, acceleration dynamics are improved and the braking distance of the vehicle is shortened. This argument is a logical consequence of the false statement about increasing road grip. This means that in reality, the acceleration and braking of the car remains unchanged, but the advantage is fictitious.

Driving safety is improved due to the fact that “nitrogen” ramps are less likely to explode. There is some truth in such conclusions: tires burst under heavy load and heat, causing the air pressure in the cylinder to increase to critical. Nitrogen is more tolerant of temperature increases and does not increase pressure, so rubber explodes less often.

Obvious disadvantages

In general, filling your tires with nitrogen is beneficial. It is not for nothing that this gas is widely used in circuit racing and rallying. There are only two disadvantages:

• decent price for the service;
• impossibility of pumping up and loss of nitrogen mixture in case of a tire puncture on the way.

Compared to regular air, the price of filling with nitrogen is 5–10 times higher, depending on the region. Knowing what real pros and cons this procedure provides, you will make the right decision about using the service. It definitely won't do any harm.

The principle of inflating tires with nitrogen - is there any point in such a procedure?

Relatively recently, a new tempting offer has appeared in many service centers in Russia - inflating tires with nitrogen. It is worth noting right away that the service does not have domestic roots; a similar method is used in Europe and the USA for refilling tires of commercial vehicles or buses. The operating rules of any car do not say about the need for this procedure; most likely, this is the choice of the car owner himself. For the first time, wheels began to be pumped with nitrogen during Formula 1 races. A mixture of nitrogen and air filled the tires of racing cars, although according to the regulations for high-speed racing it is allowed to drive on ordinary air. Every car enthusiast has the right to decide for himself whether he needs such a procedure or not. If you listen to the opinion of the employees of the service station where this service is provided, nitrogen refilling is simply necessary, and the car owner will be told about the mass of advantages gained. However, most automotive experts are confident that this is nothing more than a new marketing ploy that allows service centers to simply siphon extra money from unscrupulous motorists. Let's deal with everything in order.

Benefits of Nitrogen

The ordinary air that every person breathes consists of 3/4 nitrogen and only 1/4 oxygen. Due to the fact that nitrogen molecules are significantly larger in size compared to oxygen molecules, when pressure leaks, oxygen and vapors, which are present in small quantities in tires, come out of the wheel. Emerging through the walls of the chamber, oxygen promotes oxidation of the cord, bead ring and disc. As a result, the strength of the tire and the level of safety while driving decreases.

A tire inflated with compressed air typically leaks at approximately 0.09 atmospheres per month. Due to its chemical characteristics, oxygen is able to penetrate the tire walls by 40% faster than nitrogen. It is almost impossible to eliminate penetration; it will continue until the same gas pressure is created. However, if you follow the rules and pump oxygen into the tire, the level of which for passenger cars will not exceed 5%, and for trucks 2.5%, the partial pressure will be balanced and a leak will not appear.

Advantages of the modern process

The use of nitrogen, according to service station employees, brings considerable benefits to its owners:

• tires practically do not wear out or age, the possibility of wheel corrosion disappears, this is ensured due to the complete absence of moisture and dust - all those particles due to which the performance of wheels regularly decreases;
• Tire explosion is reduced to a minimum. During long driving at high speed, the tires do not heat up or expand, and there are no brake slips;
• The tire pressure level stabilizes. If with normal air you have to check the pressure level every two weeks, then nitrogen in the tires allows you to “forget” about it for 1.5 months.
• grip on the road surface increases. Pure nitrogen has an increased level of damping properties, due to which the wheels function as another shock absorber;
• The driver and his passengers will be able to pass through various potholes and inclines of the road as smoothly and gently as possible;
• tire depreciation increases, while reducing the load on the car’s suspension;
• driving your own car becomes simpler and easier;
• the car acquires additional stability when cornering, during lane changes and exits;
• braking distance is significantly reduced and road grip is increased;
• during a sudden start of movement, wheel slip disappears or is reduced to a minimum;
• while driving, the car “walks” along the road almost silently, that is, the noise that usually appears as a result of the tires touching the road decreases or disappears;
• Filling the wheels with nitrogen allows you to reduce fluctuations in pressure levels, and this happens regardless of the speed of movement, the load of the machine and environmental indicators;
• Tire wear and wheel damage are reduced during unforeseen situations, for example, when a wheel gets into holes or hits curbs;
• the material from which the disc is made does not oxidize.

However, the main argument that the service center workers give is not an improvement in the performance of the tire, but complete safety guaranteed to the car owner while driving on any road surface.

The pressure level in tires with nitrogen remains virtually unchanged

The process of inflating tires with nitrogen

If we talk about how the process of pumping nitrogen into car tires occurs, we should mention nitrogen generators. A similar installation for inflating tires with nitrogen is a specialized device that, during rotation, helps transform the air mixture. Before entering the tire, the air undergoes several significant treatments. First of all, a huge amount of compressed air is supplied to the generator; its volume should not be less than 8 atmospheres. Next comes detailed filtering, which also consists of several levels. The pumped air is completely degreased, all unnecessary impurities are removed from it, in particular, moisture, oil impurities and fragrances in the form of hydrocarbons. Clean air, passing through the internal membranes, loses nitrogen molecules.

As a result, a fairly long air treatment cycle allows you to understand why so much effort was spent - the nitrogen at the outlet is 95% pure. According to experts, such a ratio of the air mixture, in which oxygen has only 5%, is an ideal composition for filling car tires.

Installation for inflating tires with nitrogen

Inflating the wheels occurs as follows: the tire valve is connected to a special unit that has previously cleaned the air and filled the tire under pressure. A wheel inflated in this way does not allow oxygen and moisture to enter. Thanks to this, the tire disc will not be subject to corrosion and, therefore, will not be able to lose its seal.

Opposing opinion or disadvantages of the procedure

From the above arguments, it becomes clear why inflate tires with nitrogen - first of all, the car owner ensures his own safe driving, while traveling in more comfortable conditions.

However, some motorists consider providing such a procedure the easiest way to “force” the car owner to pay more money to qualified service center specialists. This category of people gives the opposite arguments in their favor:

• inflating the tires two-tenths of an atmosphere less than the usual level will allow the car owner to feel unusual softness while driving;
• the load on the car’s suspension, if it decreases, will be completely insignificant, because the mass of pure nitrogen molecules is only 7% lower than air, which is why such a small difference will not be noticeable either for the driver or for the car;
• Nitrogen is not pumped into the wheels to improve the safety of passengers and the driver. Nitrogen is “poured” into racing cars due to its chemical properties, in particular, eliminating the possibility of combustion, i.e., if the car catches fire during a race, wheels inflated with nitrogen will simply reduce the consequences of the fire.
• Despite the fact that nitrogen molecules are larger, any tire is capable of deflating air naturally.

Before inflating the wheel with nitrogen, it is necessary to bleed the air.

In addition, you should know that inflating wheels with nitrogen cannot reduce the fuel consumption of a car.

Conclusion

Based on all of the above, the car owner must decide for himself whether he needs such a nitrogen pumping of the wheels or not. Perhaps this is just another advertising ploy of thoughtful service station employees, or perhaps there are a lot of advantages that few people know about yet. It is likely that tires with nitrogen will be able to further extend their performance and increase comfort when driving on any road surface.

Does it make sense to inflate tires with NITROGEN?! (C)

The fashion for such a service appeared relatively recently. Where exactly it came from is quite difficult to establish. There was an opinion that tires began to be inflated with nitrogen on Formula 1 racing cars. How reliable this information can be is unknown. They say that nitrogen cylinders began to be used in racing because they made the process of inflating car tires easier and faster. Positive factors that influenced this also included: better vehicle controllability and lower fire hazard. In our opinion, these factors are rather doubtful, since the car’s wheels do not inflate during the race. And in the event of a fire, “nitrogen” tires are unlikely to affect anything. However, this is purely our opinion, we do not undertake to assert anything. Let's better talk about other factors that answer the question: why inflate car tires with nitrogen?

Everyone knows that the atmosphere of the earth, in other words ordinary air, consists of almost 80% nitrogen, about 15% oxygen, the rest is water vapor, helium, argon, carbon dioxide and hydrogen. In tire shops they offer us a mixture that consists of 5% oxygen, the rest is nitrogen. If we take into account this fact, we can already think about whether it is worth switching to pumping wheels with pure nitrogen? We have come across several statements that people use when saying that nitrogen should be pumped into tires. These are the arguments:

1. Tires will become soft. Those people who understand at least a little physics will tell you about the stability of pressure in a tire. In the sense that when a tire heats up, the pressure in a tire filled with nitrogen will hardly change, and even if it changes, it will be many times less sensitive than in a tire with regular air. In other words, the ride becomes softer, but it will be extremely difficult to check this, since the softness of the ride is a subjective concept. This feeling can be compared to a train ride on a car after washing it. “When it’s clean, the car rides much smoother and steers better.”

But the second part of the statement contradicts the laws of physics, which we study in our school years. Specifically: according to the law of Charles and Gay-Lussac. Tire fittings have their own nuances, after applying which you will be completely confident that the nitrogen in the tires has made them ride softer and smoother. They consist in the fact that a mixture with lower pressure is supplied to the tire, so if you still decide on such an experiment, check the tire pressure with your tire pressure gauge.

2. This statement states that if you inflate a tire with nitrogen, then the wear of the disk and the aging of the rubber will be less, as if this is due to the lower content of oxygen in the mixture. The statement is very difficult to believe, since there is some truth in it. However, car tires are largely influenced by external factors, such as snow, water, road surface, and our standing starts. So, you will change the tires of your car faster than waiting for the detrimental effect of the percentage of oxygen on the tires from the inside.

From the inside, the corrosion of the disc will decrease because there is much less oxygen in the composition. It is worth noting again that the disk mainly oxidizes and rusts on the outside, however, some of the benefits of using nitrogen are still present

3. We also came across the opinion that the wheel pressure, if nitrogen is pumped into them, will need to be checked much less frequently. It seems that due to the fact that there is a difference in the pressure of oxygen and nitrogen, wheels inflated with the latter will flatten much less. We delved into the reference book and compared the sizes of the molecules, and then estimated their percentage (it’s not worth going into details, but the difference it turned out to be about 7%). In other words, the difference in leakage is so small that it is not worth taking into account. Modern tires can maintain stable pressure for a long time.

4. The likelihood of a tire exploding will be much less. This is due to the fact that nitrogen is an inert gas and will not support combustion.

The tire does not “explode” at all (as some may imagine), but bursts. The sound that is made during an “explosion” is just a sudden loss of pressure, which, as a rule, is caused by a car colliding with a foreign object or as a result of the destruction of the structure of the tire itself. In Formula 1, nitrogen is actually pumped in because of fire safety, since in the event of an accident, when it comes out, it will not contribute to combustion.

There are other dubious statements that contradict the elementary laws of physics, but you should not focus on them. To sum up, we can say that a large number of theses that we are used to hearing in advertising do not correspond to reality, and some of them are outright deception.

There is also a psychological factor in this; those people who inflated their tires with nitrogen often claim that their car began to drive much quieter, smoother and handles better. If you want to test the laws of physics at your own expense, you can pump nitrogen into your tires.

There is one truly positive point in this procedure; pumping nitrogen into tires really won’t make things worse or better. Therefore, why inflate car tires with nitrogen if you can use regular air.

Attention! Be very careful! It is worth checking the pressure on “cold” tires with your pressure gauge (for example, in the morning, before you start driving). Because if you inflate tires with insufficient pressure, your ride will be softer, but this can lead to tire puncture and damage to the rim surface, especially if you like to drive at high speeds.

Why do you inflate tires with nitrogen and is it necessary?

Recently, most service stations (service stations) and tire shops offer a service for inflating tires with nitrogen, instead of the air that many drivers are accustomed to. According to tire shop workers, this gas has almost miraculous properties that should certainly delight every car owner. Is it really? Let's try to figure it out.

Arguments of businessmen - let’s find out if there is truth in them

To begin with, it would be nice to recall that air is a mixture of various gases, 78% of which are nitrogen. The composition produced by nitrogen generators in service stations contains a little more of it, namely 95-97%. Obviously, there is a difference, but is it noticeable in real operating conditions? And how to check the percentage of nitrogen? After all, if ordinary air is pumped in instead, the average car enthusiast will not be able to determine this. On the other hand, the question arises, what is the advantage of inflating tires with a gas mixture that contains even 99% nitrogen? Let's consider the main arguments of businessmen and determine whether they correspond to the truth.

Stable tire pressure

What they say:
According to the sellers of the service in question, changes in tire temperature while driving in no way affect the level of pressure in the chamber, since the expansion coefficient of nitrogen (thermal) is significantly lower than that of air.

As in fact:
The presented statement is not true, because it contradicts the Mendeleev-Clapeyron law, which proves a clear connection between temperature, volume and pressure, which is expressed by the formula P*V/T = const.
Admirers of the innovation object that nitrogen is not an ideal gas, and therefore “behaves” differently. When it is under pressure, then gas laws cannot be applied to it at all. To this, a person knowledgeable in physics will answer that the behavior of nitrogen, determined by the above equation, will differ significantly from the parameters of an ideal gas only when the pressure increases to tens of atmospheres. In other words, the car enthusiast will not be able to feel the effect, because the tire will simply burst. Note also that nitrogen has a volumetric expansion coefficient of 0.003372 (1/K), and for air this parameter is 0.003665 (1/K). In a standard wheel, when the temperature changes, the difference in pressure will be in the 4th decimal place. And the advantage will be in the air! However, this cannot be detected with a regular pressure gauge.

No gas leakage

What they say:
You can often hear the statement that oxygen evaporates from the wheel faster than nitrogen, and therefore the pressure in it decreases much faster, and the wheels have to be pumped up more often.

How it really is:
Nitrogen molecules are actually larger, that’s a fact.
However, their diameter differs from oxygen molecules by only 6% (0.32 nm for nitrogen versus 0.30 nm for oxygen). And air, as we know, is 99% composed of a mixture of these gases. This means that if a tire inflated with nitrogen loses exactly 1 atmosphere of pressure, then its counterpart with air will lose 1.012 atmospheres in the same period of time. Can you feel, notice or measure this difference? On the other hand, if oxygen completely evaporates from the chamber, then almost “pure” nitrogen will remain inside, which you will receive absolutely free!

Reducing tire aging

What they say:
The statement sounds very plausible and realistic that, unlike oxygen contained in the air mixture, nitrogen does not age rubber, nor does it oxidize the steel cord of a tire.

As a matter of fact:
One has to wonder how many drivers have replaced unworn tires due to rusted cords? It’s also very interesting how the tire shop employees or the car depot mechanic will respond to this? In any case, it is enough to inspect the inner surface of tires that have served their purpose and have not seen special newfangled inflation. You can’t tell right away whether the rubber has aged from the inside.

Reducing wheel weight

What they say:
Car tires inflated with nitrogen make it possible to reduce the overall unsprung weight of the suspension, since the specific gravity of this gas is lower than that of air. It's hard to argue with the facts. However, what does this look like in practice?

How it really is:
So, the density of nitrogen is 1.25 kilograms per cubic meter, and the same parameter for air is 1.29 kg/m3. Let's take a standard wheel with a chamber volume of 0.05 m3 and an operating gas pressure of 2 kgf/cm2. Having carried out simple mathematical calculations, we get a difference of six grams, which simply cannot play any role or affect the safety of the suspension, with the weight of the middle wheel being approximately 13-15 kilograms.

The tire does not overheat

What they say:
You can often hear the opinion in favor of nitrogen that a tire inflated with it does not overheat, since this gas removes heat more efficiently than air.

As it really is:
From the point of view of scientific facts, this opinion is complete nonsense.
The thermal conductivity coefficient of nitrogen is 0.0261 W/(m*K), and that of oxygen is 0.0269 W/(m*K). It is obvious that the difference in indicators, although insignificant, is there. At the same time, it speaks in favor of air that contains oxygen, which promotes better heat transfer and more efficient cooling. The heat capacity of nitrogen is 13% higher than that of oxygen. However, do not forget that the latter is only about 21% in the air. Consequently, in a tire, nitrogen’s ability to accumulate heat is simply neutralized.

Increased security

What they say:
Service station workers who suggest inflating tires with nitrogen claim that in the event of a fire, such a wheel cannot explode, since this gas does not burn.

How it really is:
Here it should be said that if a car catches fire, then 50 grams of oxygen in each tire will not make a difference. And rubber with nitrogen will suffer no less than its counterpart with air inside.

Conclusion

As a conclusion, here are three more of the most popular arguments provided by admirers of the newfangled pumping.

• Tires with air need to be pumped up, but using nitrogen, this problem disappears. Most likely the problem is the new tires, and not the gas with which it is filled. The wheel should maintain the specified pressure for many months without damage. Otherwise it is faulty.
• A car whose wheels are inflated with nitrogen moves smoother, and the level of vibration and noise is noticeably lower. This “phenomenon” has a banal explanation. When filling the tire chamber with nitrogen, in most cases, the wheels are not inflated by 0.2-0.3 atmospheres. This creates a feeling of increased smoothness and comfort. However, nitrogen has absolutely nothing to do with it in this context.
• In Formula 1 racing, tires are inflated exclusively with nitrogen. This is a well-known fact, which is regulated by paragraph 12.7.1 of the rules of these races, which states that car tires can only be filled with nitrogen or air. Here the emphasis can be placed on the conjunction “or”, indicating that even for high-speed cars that can withstand colossal overloads, there is no difference between the gas compositions under consideration.

In any case, everyone decides for themselves what and how to inflate the wheels of their vehicle. Nitrogen will bring neither benefit nor harm to the car, which cannot be said about the driver’s wallet, because inflating tires with nitrogen costs 10-20 times more. So who is “cheating” whom in the end?

Nitrogen in tires is a scam. But there are real ways to save!

But that’s in sports. But in civilian life, we see fires during car accidents much less often. After all, designers have worked hard to reduce the fire hazard in an accident.

Price issue

When you arrive at a tire shop and succumb to persuasion to fill your tires with nitrogen, you will see that the air from your car’s tires will first be pumped out and then filled with nitrogen from a special installation. The pressure will be set according to the technical requirements of the vehicle manufacturer. This procedure will cost from 180 to 260 rubles per wheel. The larger the diameter, the more expensive.

Advertising stunt

At a branded expensive tire service, almost any car owner, and especially the owner, will probably be offered to inflate their tires with nitrogen. There are a lot of arguments in favor of this procedure. Let's figure out which of them are true and which are fiction:

1. The tire pressure will be stable because nitrogen hardly expands when heated. But the air already contains 78% nitrogen, so the changes account for the rest of the gases, which also do not expand beyond measure. The difference in the coefficient of volumetric expansion is negligible with a significant figure in the fourth decimal place.
2. Nitrogen molecules are larger and therefore do not penetrate outward through the tire walls as quickly, keeping the pressure stable. But do not forget that there is not so much oxygen with other gases - about 22%. And when they begin to evaporate, and we begin to pump up the tire, the nitrogen concentration will increase. So, a 5-6-year-old wheel develops an almost purely nitrogen “atmosphere” inside.
3. A wheel filled with nitrogen is lighter than a wheel inflated with atmospheric air. This saves fuel. Simple calculations show that the wheel of a mid-size crossover will be lighter by only a few grams. How much do the pebbles stuck in the tread weigh? Let's clean the tread more often, especially since tire design engineers highly recommend it.
4. The absence of oxygen protects the tire material from premature aging. Tire manufacturers support this thesis, but you don’t hope that after a century your tires will be located on a pedestal, like the wheels of Lenin’s armored car. Wear and aging of the outer layers of rubber under the influence of the sun, ozone, and moisture occurs much faster.
5. Better road grip and greater safety due to stable performance. I don’t agree: you still need to check the tire pressure periodically, and with each “puff” precious nitrogen will be released. And you can’t let yourself down. This is how servicemen strive to tie a car enthusiast to their workshop even for such an insignificant problem as checking pressure and inflating a tire.

Real alternative

• Timely seasonal tire replacement that meets both legal requirements and common sense. Summer tires definitely roll easier!
• Before long trips on the highway, increase the tire pressure by 0.2 bar. It will be a little tougher, but noticeably more economical.

• Use lightweight wheels, not just any alloy wheels, but preferably forged ones; they often have a noticeably lower weight. In general, choose wheels not by design, but by weight. But to ensure lightness without sacrificing durability, look for certified rims.

• Use tires made using Energy saver technology. Many manufacturers have these today. They have slightly lower rolling resistance thanks to the use of technologies designed specifically for resource conservation.
• Choose tires using the results of the “Behind the Wheel” tire tests, where each candidate’s rolling resistance is measured, among other things.
• Install light-alloy (and really light) wheels of a larger diameter and select the appropriate tires using a tire calculator, while maintaining the outer diameter of the previous wheel. Well, or a little more.
• You drive a lot on the highway, but with a light load, or the gears in your car’s gearbox can be called “short”, such as, for example, in the Renault Logan or Lada Largus. That is, at 100 km/h the engine makes more than 3000 rpm in top gear. Then you can install tires with a slightly larger diameter. This will make all gears a little longer and will save fuel.

The free and best way to save fuel with the tire question is to maintain the manufacturer's specified inflation pressure. And a slight increase in this pressure before long trips on the highway.