How many atmospheres do you need in a bicycle wheel? What pressure should bicycle tires have? Road bike tire pressure

Every cyclist should check the tire pressure of his bicycle before riding his two-wheeled friend. This may not seem like a big deal, but a hand or foot pump can create enough pressure to cause your tires to crack and burst. To prevent this from happening, find out what your bike is rated for.

Why maintain the correct tire pressure

Mountain bike tire pressure is an individual parameter that is indicated on the tires. Usually the maximum and minimum values ​​are indicated.

That is, the value can be varied and benefits can be obtained from this.

Why maintain the correct pressure:

Weakly inflated wheels can cause the inner tube to break when hitting a small obstacle.

A value within the normal range, close to the minimum, improves traction on poor roads, especially mud and rough terrain.

A value within the normal range, close to the maximum, gives an advantage in speed and allows the driver to save energy.

Too high a pressure can cause a flat tire.

The reduced pressure smooths out road unevenness and provides additional shock absorption.

Knowing these factors can help you vary how much you inflate your tires to further benefit your ride.

Tire markings

Pressure can be measured in three quantities:

Bar – kilogram-force per 1 cm square;

Pa – Pascals;

Psi – pound-force per 1 square inch.

In Russia, Bars or Atmospheres are most often used. For bicycles from the American market, the value is measured in Psi. Pascals are rarely used.

What to pump up

It is best to purchase a high-pressure pump with a pressure gauge for your bicycle. This way you will be confident in choosing the size and will not overdo it.

The high pressure pump is used to inflate air shock absorbers; this is a rather rare product. It can be found in specialized bicycle shops.

This pump also has adapters for inflating tires. But this process will take more time since it is designed for small shock absorbers. But the wait time is worth it, because you can adjust the pressure level with an accuracy of one bar.

Another useful feature of this pump is the overpressure relief valve. If you missed the required value, you can press the valve and the excess air will come out.

Standard pressure from BikeHike

When inflating tires, use the values ​​indicated above. The manufacturer writes the range on the tire so you can choose the right value for the road surface. It is believed that the maximum specified value is for a hard asphalt road. It is better to leave the minimum value if you ride on a country road or in the forest.

If you drive with minimal pressure on the asphalt, you will lose speed and have to work harder with your legs. On a dirt road, additional shock absorption is needed, which is provided by low pressure. It also improves traction, which is an added benefit.

Types of bicycles and correct tire pressure for 26 inches: table

There are different types of tires and bicycles. For each type, recommended values ​​have been developed, which have been tested by many cyclists.

For mountain tires designed for extreme sports, pressure selection must be done experimentally. It is individual for each cyclist.

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Crosscountry tires are universal, they are usually inflated to 3-4 bar. They can be ridden in rural areas and on tough city roads.

Semi-slick tires are produced specifically for asphalt roads. Therefore, they must always be pumped up to the maximum value. If you inflate too little, the contact patch with the road will increase and it will be difficult to achieve high speed.

Road Bike Tire Pressure Chart:

Tire diameter in inches	Bar	Psi
12	2,4	35
14	2,4	35
16	2,4	35
18	2,4	35
20	2,5	35
24	4,5	35-65
26	4,5	35-65
28	4,5	35-65

These are maximum values, the most important thing is not to exceed them so that the tire does not burst. It's best to keep road bike tire pressure a few tenths of a bar below the maximum.

The maximum comfortable pressure should be in the wheels of a bicycle designed for mountainous terrain. It depends on the weight of the cyclist and the degree of roughness of the terrain. You also need to consider the width of the tires. The larger it is, the higher the pressure should be.

It is best to choose the optimal value for yourself in practice by riding through the mountains with a pressure gauge.

The tire pressure of a 26 inch bike depends on the person riding it.

Children's bicycles

For children, it is better to inflate tires to the maximum allowed value. This will make learning to ride a bicycle easier, since well-inflated wheels have a smaller contact patch and the rider has to exert less effort.

How to check pressure after inflation

The only way to accurately check the value is with a pressure gauge. Therefore, you need a pump with a pressure gauge or a separate electronic pressure gauge for bicycles. You can contact a car service to check the pressure and pump up the tires. But before you pump up your bike with a car pump, think twice. After all, a car repairman may not pay attention to the pressure and ruin your tires.

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Experienced cyclists can determine pressure by eye. You can inflate your tires with a pressure gauge, remember the value, and squeeze the tire with your fingers. Remember the feeling, so you will learn to understand how inflated your tires are.

Signs of Inadequate Tire Pressure

A breakdown is the surest sign that you have inflated your tires incorrectly. It can occur either from a value that is too low (less than what the manufacturer recommends) or from a value that is too high. If you cannot visually and by touch determine the degree of inflation, measure the pressure with a pressure gauge.

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Now you know what pressure should be in your bicycle tires. It is better to pump it up with a pump with a pressure gauge, which will help you choose the optimal value.

The pressure in the bicycle tires should be such that the contact patch at the point of contact between the tire and the roadway is maximum.

Each tire indicates the nominal and maximum internal pressure values. For example, writing min 2.1 Bar – max 3.8 Bar means that the bicycle tire needs to be inflated with air at a pressure of 2.1 to 3.8 atmospheres. The range of nominal pressure is huge - almost 2 atmospheres. So how much do you need to pump in order to feel confident on the road and not cause damage to the tire? It's simple, the pressure depends on the type of surface you are going to ride on.

When driving on a dirt forest road, it is necessary to inflate the tire closer to the minimum value of the permissible range. When driving on asphalt - closer to the maximum mark of the specified range. Based on the image above, we can conclude that the pressure of a bicycle tire directly depends on the type of surface on which the cyclist is riding.

What determines the pressure in bicycle tires?

Bicycle tire pressure also depends on the type of tire. So, for example, the pressure in bicycle tires - the table for road types is as follows:

And for mountain bikes, the tire pressure table by size looks different:

Never inflate the pressure in bicycle tires to the maximum value; always leave a small margin of 0.2 - 0.4 atmospheres. This will protect you from an unexpected tire explosion or cracking. Excessive tire pressure will have an extremely negative impact on the ride - the bike will not listen well, make a strong noise from the wheels, and it will become more difficult to pass uneven roads.

Be sure to carry a pump with you to inflate your bicycle tires if they are flat. You can also use a car compressor to inflate bicycle wheels, but due to its large dimensions, enormous weight and the need for a voltage source, it is not advisable to take it with you. That is why we recommend purchasing a high-pressure bicycle pump, which will cost no more than 2,000 rubles, but will come in handy, as always, at the most inopportune moment.

Bicycle tire pressure symbols

The tire's rated pressure range is always indicated. Typically, manufacturers indicate the minimum and maximum pressure values ​​in two or three dimensions at once - in atmospheres (Bar), in pascals (Pa) and in pounds-force per square inch (Psi). If suddenly, the data on your tire is indicated in only one system, then you can easily use the conversion formula: 1 kPa = psi * 6.895.

The pressure of the rear wheel of a bicycle is always slightly greater than that of the front. For a heavy cyclist, it is recommended to lower both wheels by 0.2 - 0.6 atmospheres, and for a child, on the contrary, to bring the internal pressure closer to the maximum permitted value.

The quality and type of tires affects the coasting (rolling) of a bicycle. The tire's sidewall material, tread pattern, and pressure also affect rolling ability.

Any cyclist knows that you can't do without a pump. Tires need to be inflated constantly. Moreover, the pressure is lost not only when driving, but also while it is parked (just not so fast).

What determines the pressure in a bicycle tire? Firstly, ride quality. With softly inflated tires it is more convenient to overcome uneven road surfaces, with heavily inflated tires the bike goes faster. Secondly, pressure affects how long the tire will last and whether it will have punctures. If speed and riding comfort are a matter of taste, then you need to take care of the integrity of the rubber. It's not even a matter of what will have to be repaired. In some cases, when the pressure in a bicycle tire is incorrectly selected, not only damage is possible, but also severe damage to the wheel and injury to the cyclist.

The easiest way is if you have an ordinary tire. The tire pressure on sports models needs to be monitored more carefully, especially with a hard driving style and on difficult roads. For those who prefer to ride on an asphalt highway or rural paths, it is enough to focus on the Manufacturer took care in advance and put inscriptions on the side surface about what pressure should be in the wheels of the bicycle. It is usually indicated in psi or bar (translated using the following formula: 1 kPa = psi * 6.895, recall that 100 kPa ~ 1 kg/cm^2 ~ 1 bar.) Without inflation, the tire loses up to 15 psi once a month.

For recreational bicycles, tire pressure can vary from 1.5 to 4.5 bar, which can be found out in more detail by looking at the markings. The upper limit is preferable for those who drive on hard and flat ground, the lower limit is preferable for those who are more likely to encounter stones, puddles and grass.

The pressure in the rear wheel should be slightly higher than in the front. For a heavy rider, the numbers should be reduced, and for a child, accordingly, increased.

A pressure gauge is required for measurements. Now many are equipped with this device right away, but we must take into account that a small square pressure gauge often gives a large error. When this is critical, it is better to purchase a measuring tool separately. And owners of tires with car valves can pump up and measure the pressure in them at a gas station.

An experienced cyclist can determine tire pressure without the help of instruments. You need to grab the tire with your hand and press on the tube with your thumb. The right amount of pressure will feel like you are squeezing a ripe watermelon.

But within acceptable limits, you can inflate the wheels in the way that is most comfortable for you to drive.

So, many people prefer the pressure in their bicycle tires to be higher. After all, it is convenient on the move. But for beginners, on the contrary, it is recommended to reduce the pressure. And if you want your wheels to last as long as possible, choose the optimal (or average) value of 3 bar or 45 psi.

Oddly enough, first of all, the quality of cycling, especially on asphalt, depends on the pressure in the bicycle wheels. Underinflated wheels easily break through and absorb a large percentage of the cyclist’s efforts, while overinflated wheels can damage the tube and lead to its rapid wear. Accurate knowledge and riding experience will help you find the golden mean.

Effect of pressure

In fact, the optimal pressure in bicycle tires is a purely individual parameter, which each biker varies within certain limits for himself: for his riding style, for the planned route and current level of training. The limits are set by technological limitations, which we will consider further.

Here are the main factors to consider when choosing your inflation level:

• high pressure gives “rolling” - rolling speed, saving the cyclist’s strength;
• excessively high, in turn, can provoke a breakdown of the chamber on the rim from the inside;
• similarly, low pressure leads to “snake bites”, when the rim on an obstacle or bump pierces the chamber at two points at once and reaches the tire;
• low pressure helps prevent damage to mechanisms on numerous potholes;
• at low pressure there is better “grip” and it is easier to move over rough terrain.

Taking into account all the pros and cons, we can come up with a single recommendation: the wheels should be inflated enough to provide good traction and not cause damage to the tube. For this purpose, there are standards for what pressure is considered acceptable. We will consider them further.

What is written on the tires

The secret to making the right choice is very simple: just look at the inflated tire. Next to the information about the tire size there will also be information about the permissible pressure range in the chamber.

Why is this information not indicated on the camera itself? Because in it the only point subject to real load is the nipple, and its mechanism is very reliable. Otherwise, the normal pressure, which increases by an order of magnitude when riding fast, is taken by the tire, and how much it will be compressed is the main limitation.

Camera with restrictions marked in Psi

So, if the pressure is too low, the tire will break closer to the rim, bite the tube, leading to a breakdown, and if it is high, it may simply burst on one of the bumps or when driving on hot asphalt.

How is blood pressure measured?

Pressure is denoted in three units of measurement:

• Psi – pound-force per square inch – pound-force per square inch;
• BAR – bars, usually equated to a measurement in “atmospheres”;
• Pa – pascals.

Since many tire manufacturers focus on the American market, you can most often find the designation Psi. In English-language sources it is usually simplified to “pound”, or pound, i.e., when they say that a pressure of 2 pounds, they mean Psi. This unit of measurement is outdated, used only in the USA, but, as they say, “more alive than all living things.”

Data from a smart pressure sensor on a smartphone screen

Bars also belong to outdated units of measurement, but are actively supported in Russia and many other countries, incl. European. This unit of measurement is actively used, as it echoes the “atmosphere” that is quite convenient for measurements.

Pascal is the only metrically correct unit of measurement from the list, but is rarely used in bicycle notation.

The relationship between all units is as follows: 1 Bar = 100,000 Pa = 14.504 Psi.

Markings

What do they write on the tires? For example, (2.38-4.0) is clearly atmosphere, or BAR, and (95-135) is Psi. If the number has more than 3 digits or the prefix “k” (kilo), we are talking about metric Pascal. Most often, the desired value is located under the size designation and is duplicated in BAR and Psi in the form of a range, clearly indicating to what pressure it can be pumped.

Actually, the manufacturer indicates by range the limits within which the tire can function, then – the freedom of the cyclist.

What to pump up

A bicycle tube requires maintenance and inflation very often. Even on the most “hardy” city and mountain bikes, it is necessary to check and inflate the tube once every 2-3 weeks, since air leaks not only through the nipple, but also simply through the rubber. High pressure “helps” air molecules find their way through an insufficiently dense chamber.

“City” bikes, or simply budget bikes, need to be inflated once every 2-4 weeks, mountain bikes – at least once every two weeks, road bikes – once a week, and road and sports bikes – before each trip.

Therefore, the pump is not only an emergency accessory, which is used only when changing a flat tire, but also a necessary part of preparation for departure. Actively riding cyclists should consider purchasing two pumps:

• portable – as part of an emergency kit or on long trips;
• stationary with a stop and a pressure gauge - for periodic maintenance of your tires.

By the way, a regular car pump perfectly takes the place of a stationary pump. It is also suitable for bicycles, it shows exactly how many atmospheres are inflated, and does not take up additional space. Some people prefer to inflate with “professional” pumps at gas stations, but the absence of their own professional tool can play a bad joke in case of an unexpected situation or when deviating from the standard route.

Standard pressure

Here are a few tables that will help you navigate difficult situations, namely:

• an unknown tire without markings was purchased;
• no physical access to the bike;
• The markings are unclear; the numbers are in unknown units.

Mountain bike table:

For a road bike, the pressure should be much higher, and usually varies between 6.5 – 9 atmospheres (up to 130 Psi), up to the maximum specified by the manufacturer.

Changes by season

Seasonal adjustments are quite serious, mainly for mountain bikes. In summer, you should lower the pumping slightly and not go to the maximum. Hot asphalt also heats the air inside the chamber, which increases the volume and, therefore, the pressure. Also, an overinflated tire wears out very quickly.

In winter, you should sometimes slightly exceed the maximum in order to achieve maximum performance from the tread, especially if the tire is chosen with studs.

Changes in weight

For heavy riders or seriously loaded bikes, it is very important to add pressure, because a large mass will compress and problems with insufficiently inflated tubes can come out much earlier.

Approximate values ​​by tire type

For slicks and semi-slicks, the use of pressure below the maximum is allowed only in hot weather - a shortage of a quarter already negates the entire effect of such rubber, because it is “tailored” to the maximum diameter and lack of resistance.

Classic cross country protectors 2-2.3 inches wide are inflated to 3-4 BAR, depending on the route and habit, a lower value will make riding a strength training, and larger values ​​are simply not allowed by the manufacturers, as they lead to a real “explosion” at peak load.

Extreme tires, whether 2.3+ wide compound tread downhill or BMX stunt models, should be inflated moderately, between maximum and minimum, to have sufficient grip, and then subtly varied for each trick or descent.

Conclusion

Bicycle tire pressure is a very important parameter, you should understand what restrictions are imposed by tire manufacturers and what riding style of a particular rider can be improved with just a couple of movements of the pump handle. In any case, how many atmospheres to pump at each moment is a unique decision, and it is made more based on accumulated experience than according to strict rules.

For normal atmospheric pressure, it is customary to take the air pressure at sea level at a latitude of 45 degrees at a temperature of 0°C. Under these ideal conditions, the column of air presses on each area with the same force as a column of mercury 760 mm high. This figure is an indicator of normal atmospheric pressure.

Atmospheric pressure depends on the altitude of the area above sea level. At higher elevations, the indicators may differ from ideal, but they will also be considered the norm.

Atmospheric pressure standards in different regions

As altitude increases, atmospheric pressure decreases. So, at an altitude of five kilometers, pressure indicators will be approximately two times less than below.

Due to the location of Moscow on a hill, the normal pressure level here is considered to be 747-748 mm column. In St. Petersburg, normal pressure is 753-755 mm Hg. This difference is explained by the fact that the city on the Neva is located lower than Moscow. In some areas of St. Petersburg you can find a pressure norm of an ideal 760 mm Hg. For Vladivostok, normal pressure is 761 mmHg. And in the mountains of Tibet – 413 mmHg.

Impact of atmospheric pressure on people

A person gets used to everything. Even if normal pressure readings are low compared to the ideal 760 mmHg, but are the norm for the area, people will.

A person’s well-being is affected by sharp fluctuations in atmospheric pressure, i.e. decrease or increase in pressure by at least 1 mmHg within three hours

When pressure decreases, a lack of oxygen occurs in a person’s blood, hypoxia of body cells develops, and the heartbeat increases. Headaches appear. There are difficulties with the respiratory system. Due to poor blood supply, a person may experience pain in the joints and numbness in the fingers.

Increased pressure leads to an excess of oxygen in the blood and tissues of the body. The tone of blood vessels increases, which leads to their spasms. As a result, the body's blood circulation is disrupted. Visual disturbances may occur in the form of spots before the eyes, dizziness, and nausea. A sharp increase in pressure to large values ​​can lead to rupture of the eardrum.