It would seem that it could be simpler — pumped up, crushed his fingers, went. But no, there are subtleties here. Tire pressure is the most important factor, affecting the roll, patency and control of the bike.
I deliberately do not touch tubeless tires, because they are installed on more expensive bikes, and this is a topic for a separate article.
Why is it important to inflate tires to the correct pressure?
Let's start with the very basics, here's the bike going down the road:
- The more inflated the tires, the better rolls, less fatigue
- The heavier the cyclist, the more you need to inflate
- The more inflated the tires, the more it shakes on bumps.
- If the pressure is weak, then moving over the curb, you can pierce the camera on the edges of the rim (snake bite)
And now the logical question is how to find out in what framework you need to download, how many specific atmospheres to pump? The pressure in bicycle tires is measured in atmospheres (BAR) or PSI, and most often, the permissible range is written on the tire sidewall in PSI (one atmosphere is equal to 14.7 psi). Here is an average table for an average cyclist riding without extreme sports on asphalt and primers.
This information is quite enough for you to make it comfortable enough to ride, while the tires will not suffer from pumping or under-inflating. Well, for those who care about the details - we go deeper.
Road bike tire pressure
With bikes for paved roads, everything is simple - the more pressure, the better the roll. Look at the sidewall of the tire, there must be a valid value written there, in psi, or in bar (atmosphere). If the maximum value is, for example, 8 Bar, then score 7.5 and enjoy the speed.
I will add that the air is etched through the rubber itself, and in about a couple of weeks the pressure drops by 1-2 atmospheres. This is not felt with your fingers, so a floor pump with a pressure gauge is most welcome.
If you inflate a road tire below average, you can catch a tube breakdown, called a snakebite. This occurs when the wheel hits a hard object and the tire is punched through to the rim. The result is two small holes that look like a snake bite.
Mountain bike tire pressure
Off-road bikes are a little more difficult. The fact is that here you need to strike a balance between grip and coasting. The more inflated the tire is, the better it rolls (on a flat and hard surface), but because of the rigidity, it cannot “lick” the surface - grip deteriorates.
High pressure maintains a semi-circular tire profile, while maximum grip is possible when the entire contact patch area is involved. In other words, the more the tire “flattens out”, the better it is for cross-country ability and control. On the other hand, if you pump too little, the roll will suffer and the same “snake bite” is possible.
Since basically all chambered mtb rubber has an allowable pressure range of about 2-4 atm, I would say that the working pressure lies between 2.2 and 3 atmospheres for an adult male, weighing from 75 to 90 kg. It is impossible to be more precise - there are a lot of factors, you need to experiment with a specific tire and a specific trail where you ride.
Different rubber behaves differently at the same pressure, and the behavior also depends on the width of the tire, it is believed that less pressure can be pumped into a wider one. The weight of the cyclist is very important, for obvious reasons.
Take a pump with a pressure gauge with you and try to find the lower limit of pressure at which the tire has not yet broken through. Then try how the bike rolls at that pressure. Add air if needed. It is necessary to find a middle ground for both soil and asphalt.
Fat bike tire pressure
A fatbike is designed to ride on loose surfaces, its huge, large-volume tires must spread over bumps, this is achieved by low pressure.
The Fat is the perfect winter bike, so let's talk snow riding. For an 80kg rider, the following figures may be acceptable:
Fat rolls much better on loose snow if you pump less than 5psi. But reducing the pressure below this line for chamber tires can be a bad decision - the bike starts to steer poorly, “float”, the nipple may break or cut off due to the rotation of the chamber. Therefore, I recommend switching to, the bike will roll better and more stable at extremely low pressure.
In addition, do not forget from such a trifle that since you have much less atmosphere in your tires, temperature fluctuations will be reflected in real pressure. For example, at home it was 7psi, we left for a frost of 10 degrees, it became 4.3. Here is a table for you to calculate the approximate dependence on temperature:
| Pressure in the chambers depending on the outside temperature | |||||||||||
| Room temperature, °C | Outside air temperature, °C | ||||||||||
| 25 | 10 | 5 | 0 | -5 | -10 | -15 | -20 | ||||
| 740 | Atmospheric pressure, mm Hg | ||||||||||
| psi at room temp. | psi outside depending on temperature | ||||||||||
| 4 | 3,0 | 2,7 | 2,3 | 2,0 | 1,7 | 1,3 | 1,0 | ||||
| 4,5 | 3,5 | 3,1 | 2,8 | 2,4 | 2,1 | 1,7 | 1,4 | ||||
| 5 | 3,9 | 3,6 | 3,2 | 2,9 | 2,5 | 2,2 | 1,8 | ||||
| 5,5 | 4,4 | 4,1 | 3,7 | 3,3 | 3,0 | 2,6 | 2,2 | ||||
| 6 | 4,9 | 4,5 | 4,1 | 3,8 | 3,4 | 3,0 | 2,7 | ||||
| 6,5 | 5,4 | 5,0 | 4,6 | 4,2 | 3,8 | 3,5 | 3,1 | ||||
| 7 | 5,8 | 5,4 | 5,1 | 4,7 | 4,3 | 3,9 | 3,5 | ||||
| 8 | 6,8 | 6,4 | 6,0 | 5,6 | 5,1 | 4,7 | 4,3 | ||||
| 9 | 7,7 | 7,3 | 6,9 | 6,4 | 6,0 | 5,6 | 5,2 | ||||
| 10 | 8,7 | 8,2 | 7,8 | 7,3 | 6,9 | 6,4 | 6,0 | ||||
Air pressure for different types of tires
If you have semi-slick, the low pressure nullifies its advantages. The purpose of a semi-slick is to roll on a hard surface with a smooth part of the tread due to the semi-circular profile of the tire. And only when it hits soft ground, the lateral part of the tread comes into play.
And if the tire is poorly inflated, then it will be flattened, and your semi-slick will even row on asphalt with its lugs. Therefore, we pump close to the maximum pressure into this type of tire.
Standard cross country tires 2.1-2.3 inches wide require a working pressure of 3-4 atm. This rubber has not too pronounced lugs, these are the most versatile tires for those who ride in the forests.
Tires for more extreme riding have a width of 2.3″ or more, and traction is very important here. The pressure is calculated experimentally so that the tire does not break through on drops and hard descents.
How much to pump in tires in winter
If you ride a bike in cold weather, then you need to take into account that in the cold the pressure drops a little, so at home pump up about 20% more than normal so that everything on the street comes into balance.
_____________________________
Here I have described different styles skating, I advise you to see.
I would not want readers to imagine a cyclist with a pump that does nothing but put different pressures under different conditions.
In fact, finding the golden mean is quite simple, you just need to dedicate half an hour. I advise you to pay attention to this issue, if you are a beginner, then most likely you did not even think about it.
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Oddly enough, first of all, the quality of cycling, especially on asphalt, depends on the pressure in the bicycle wheels. Under-inflated wheels easily break through and extinguish a large percentage of the efforts of the cyclist, while over-inflated ones can damage the tube and lead to its rapid wear. Accurate knowledge and experience of riding will help you find the golden mean.
pressure effect
In fact, the optimal pressure in the tires of a bicycle is a purely individual parameter, which each biker varies within certain limits for himself: for his riding style, for the planned route and the current level of training. Limits are set by technological restrictions, which we will consider further.
Here are the main factors to consider when choosing an inflation level:
- high pressure gives "rolling" - rolling speed, saving the cyclist's strength;
- excessively high, in turn, can provoke a breakdown of the chamber against 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 prevents damage to mechanisms on numerous bumps;
- at low pressure, the “hook” is better and it is easier to move over rough terrain.
Considering all the pluses and minuses, one recommendation can be made: the wheels should be inflated enough to provide good traction and not damage the camera. To do this, there are standards for what pressure is considered acceptable. We will consider them further.
What is written on the tires
The secret of the right choice is very simple: just look at the inflated wheel. Next to the information about the tire size, there will also be information about the allowable pressure range in the chamber.
Why is this information not indicated on the camera itself? Because in it the only point that is subjected to real load is the nipple, and its mechanism is very reliable. Otherwise, the normal pressure, which increases by an order of magnitude with fast skating, is taken by the tire, and how much it will be squeezed is the main limitation.
Camera marked with Psi limits
So, at too low a pressure, the tire will break closer to the rim, bite the chamber, leading to breakdown, and at high pressure, it may simply burst on one of the bumps or when driving on hot asphalt.
What is pressure measured in
It is customary to designate pressure 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, the most common designation is Psi. In English sources, it is usually simplified to “pound”, or pound, that is, when they say that the pressure is 2 pounds, they mean exactly Psi. This unit of measure is obsolete, used only in the USA, but, as they say, "more alive than all living things."
Smart pressure sensor data on smartphone screen
Bars are also obsolete 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”, which is quite convenient for measurements.
Pascal is the only metrically correct unit from the list, but is rarely used in bicycle notation.
The ratio between all units is as follows: 1 Bar = 100,000 Pa = 14.504 Psi.
Markings
What is written on the tires? For example, (2.38-4.0) is clearly atmospheres, 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 as a range, clearly indicating to what pressure you can pump.
Actually, the manufacturer indicates the range within which the tire can function, then the freedom of the cyclist.
How to pump up
The bicycle chamber requires maintenance and swapping very often. Even on the most “hardy” city and mountain bikes, it is necessary to check and pump up the chamber once every 2-3 weeks, since air leaks not only through the nipple, but simply through the rubber. The high pressure "helps" the air molecules to find their way through the insufficiently dense chamber.
"Urban", or, simply, budget bikes, it is enough to inflate 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 a punctured tire is changed, but also a necessary part of the preparation for departure. Active cyclists should consider purchasing two pumps:
- portable - as part of an emergency kit or on long trips;
- stationary with an emphasis and a pressure gauge - for periodic maintenance of their tires.
By the way, the place of a stationary pump is perfectly occupied by a conventional car pump. It is also suitable for bicycles, it shows exactly how many atmospheres are inflated, and does not take up extra space. Some people prefer to pump up on "professional" pumps at gas stations, but not having 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 some tables that will help you navigate in difficult situations, namely:
- bought an unknown tire without markings;
- no physical access to the bike;
- the marking is incomprehensible, numbers in unknown units are marked.
Table for mountain bike:
For 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.
seasonal changes
Seasonal adjustments are quite serious, mainly for mountain bikes. In the summer, you should slightly underestimate the pumping and not rest on the maximum. Hot asphalt also heats the air inside the chamber, which increases the volume and, consequently, the pressure. Also, the pumped tire wears out very quickly.
In winter, you should sometimes slightly exceed the maximum in order to achieve maximum tread work, especially if the rubber is selected with studs.
Weight changes
For heavy riders or seriously loaded bikes, it is very important to add pressure, because a lot of mass will compress and problems of under-inflated chambers can come out much earlier.
Approximate values by type of rubber
For slicks and semi-slicks, the use of pressure below the maximum is allowed only in hot weather - a quarter shortage already negates the entire effect of such rubber, because it is “sharpened” for the maximum diameter and lack of resistance.
Classic cross country 2-2.3" wide treads will inflate to 3-4 BAR, depending on the track and habit, a lower value will make riding strength training, and large values are simply not allowed by manufacturers, as they lead to a real "explosion" at peak load.
Extreme tires, be it downhill 2.3+ wide compound treads or trick BMX models, should be inflated medium between high and low to have enough traction 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 style of riding 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 on the basis of 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. In these ideal conditions a 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 height of the area above sea level. On a hill, the indicators may differ from ideal, but at the same time 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, the pressure indicators will be approximately two times less than at the bottom.Due to the location of Moscow on a hill, the pressure here is considered to be 747-748 mm of column. In St. Petersburg, normal pressure is 753-755 mmHg. 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 meet the ideal pressure rate of 760 mm Hg. For Vladivostok, the normal pressure is 761 mmHg. And in the mountains of Tibet - 413 mm of mercury.
The effect of atmospheric pressure on people
A person gets used to everything. Even if the normal pressure is low compared to the ideal 760 mmHg, but is the norm for the area, people will.A person's well-being is affected by a sharp fluctuation in atmospheric pressure, i.e. decrease or increase in pressure by at least 1 mmHg for three hours
With a decrease in pressure, there is a lack of oxygen in the human blood, hypoxia of the cells of the body develops, and the heartbeat quickens. Headaches appear. There are difficulties on the part respiratory system. Due to poor blood supply, a person may be disturbed by pain in the joints, numbness of the fingers.
An increase in 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 blood circulation of the body is disturbed. There may be visual disturbances in the form of the appearance of "flies" before the eyes, dizziness, nausea. A sharp increase in pressure to large values \u200b\u200bcan lead to rupture of the ear tympanic membrane.
Approximately one third of the population of our planet reacts sensitively to changes in the environment. Most of all, human well-being is affected by atmospheric pressure - the attraction of air masses to the Earth. What atmospheric pressure is considered normal for a person depends on the area in which he stays most of the time. Everyone will feel comfortable in the conditions familiar to him.
What is atmospheric pressure
The planet is surrounded by an air mass, which, under the influence of gravity, presses on any object, including human body. The force is called atmospheric pressure. A column of air weighing approximately 100,000 kg presses on each square meter. Atmospheric pressure is measured with a special device - a barometer. It is measured in pascals, millimeters of mercury, millibars, hectopascals, atmospheres.
The normal atmospheric pressure is 760 mm Hg. Art., or 101 325 Pa. The discovery of the phenomenon belongs to the famous physicist Blaise Pascal. The scientist formulated the law: at the same distance from the center of the earth (does not matter, in the air, at the bottom of the reservoir), the absolute pressure will be the same. He was the first to propose measuring heights by barometric equalization.
Atmospheric pressure norms by region
It is impossible to find out what atmospheric pressure is considered normal for a healthy person - there is no definite answer. The impact varies across regions of the world. Within a relatively small area, this value can vary markedly. For example, in Central Asia, slightly elevated figures are considered standard (average 715-730 mm Hg). For middle lane Russia's normal atmospheric pressure is 730-770 mm Hg. Art.
The indicators are related to the elevation of the surface above sea level, wind direction, humidity and ambient temperature. Warm air weighs less than cold air. Over an area with elevated temperature or humidity, the compression of the atmosphere is always less. People living in high mountain areas are not sensitive to such barometer readings. Their body was formed in these conditions, and all organs underwent appropriate adaptation.
How pressure affects people
The ideal value is 760 mm Hg. Art. What awaits when the mercury column fluctuates:
- A change in optimal performance (up to 10 mm/h) already leads to a deterioration in well-being.
- With a sharp increase, decrease (on average by 1 mm / h), even in healthy people there is a significant deterioration in well-being. Appears headache, nausea, loss of working capacity.
Meteorological dependence
Human sensitivity to weather conditions - wind changes, geomagnetic storms - is called meteorological dependence. The influence of atmospheric pressure on is not yet fully understood. It is known that when weather conditions change, internal tension is created inside the vessels and cavities of the body. Meteorological dependence can be expressed:
- irritability;
- pains of various localization;
- exacerbation of chronic diseases;
- general deterioration of well-being;
- vascular problems.
In most cases, weather dependence affects people with the following diseases:
- respiratory diseases;
- hypo- and hypertension.
Response to high blood pressure
A decrease in the barometer by at least 10 units (770 mm Hg and below) has a negative impact on health. People with long-standing diseases of the cardiovascular and digestive systems are especially affected by weather changes. Doctors on such days recommend reducing physical exercise, less to be on the street, do not abuse junk food and alcohol. Among the main reactions:
- feeling of congestion in the ear canals;
- decrease in the number of leukocytes in the blood;
- decreased activity of intestinal motility;
- violation of the functionality of the cardiovascular system;
- poor ability to concentrate.
In this article, we will answer the question that so many cyclists ask: what pressure should be in the tires of a bicycle? We note right away that tire pressure is the most important factor that affects the patency and rolling of your bike. That is why the pressure in the wheels must be correct.
The required pressure will help you determine the allowable values on the tires. All products, regardless of manufacturer, must be marked with the minimum and maximum allowable pressure. In rare cases, only one value is indicated - the maximum. Also, these values can be specified in different units of measurement: P.S.I. - pressure in pounds (American designation) or BAR - pressure in bars or atmospheres. In the table below, we have compared all possible values with the weight of a person, so that you can easily determine the necessary pressure based on your weight.
A floor or hand pump with a pressure gauge will help you correctly determine the pressure in the wheels. Be careful when using compressor pumps as they serve a large number of air at high speed, which may cause the chamber to explode.
When choosing the right tire pressure for your bike, you should also pay attention to factors such as:
- The surface on which you ride. So, when driving on rough terrain, dirt or sand, it is enough to inflate the tires a little above the minimum value, so traction will be better. When driving on asphalt and flat surfaces, it is better to choose a value close to the maximum - this will improve the roll forward.
- Your bike type. Depending on the type of bike you have, we recommend using different pressures. For a mountain bike, this value should be lower than, for example, for a sports road bike. Here the principle applies, the narrower the tire, the higher the pressure in it should be. And vice versa.
- Temperature outside. In the heat, it is better not to pump up the wheels to the maximum, because. The air in the chamber heats up and the pressure increases further. And in winter, even when riding on snow, the pressure should not be lower than average in order to achieve maximum tread grip.
- User weight. Inflate your tires more if you are overweight or carry heavy loads on your bike.
To sum it up, there are no hard and fast rules on how much atmosphere you should have in your wheels. And the correct answer will be your accumulated experience!
