How many atmospheres are in a children’s bike

Pressure effect

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

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

  • high pressure gives rise to rolling speed, saving the strength of the cyclist;
  • 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 a 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 better grip and easier to move over rough terrain.

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


What do they write on the tires? For example, (2.38-4.0) is clearly atmospheres, or BAR, and (95-135) is Psi. If the figure 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 you can pump.

Actually, the manufacturer specifies the range within which the tire can function, then. the freedom of the cyclist.

Approximate values ​​by type of rubber

Optimizing the inflation rate of a bicycle tire depends on the type of tire used, and in particular mainly on the type of tire. If the bike is shod in slick or semi-slick rubber, then minimizing pressure is permissible only on hot days. As shown by bench tests of slick (low-relief) tires, a decrease in the level by 25.0% to the optimal level nullifies all their advantages.

You can also give recommendations for inflating wheels with different tires.

If the bike is shod with 2.0… 2.3 inches wide tires with cross-country protectors, then the optimal pressure range is 3.0… 4.0 atmospheres (bar). A decrease in this value will require an increase in the expenditure of muscle energy, and exceeding the level of inflation of bicycle tires above the upper limit, when driving off-road, often leads to an explosive destruction of the tire.

Extreme tires (Downhill / Slalom 24 ″ × 2.10 or Kenda K905 20 x 1.95 ″) with a complex tread, are best inflated to the average recommended pressure. This will provide the necessary adhesion to the supporting surface. In the future, its indicator can be adjusted for specific driving conditions.

BMX stunt models should be inflated medium, between high and low, to have sufficient traction, and then subtly varied for each stunt.

For winter riding, it is worth choosing a pressure slightly higher than normal, since at sub-zero temperatures the air in the tire becomes denser and takes up less space.

What to pump up

Bicycle luggage requires maintenance and pumping very often. Even on the most enduring city and mountain bikes, it is required to check and pump up the camera every 2-3 weeks, since the 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, or, simply, budget bicycles, it is enough to pump up 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 that is used only when a punctured wheel is changed, but also a necessary part of the preparation for departure. Active cyclists should consider purchasing two pumps:

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  • 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, an ordinary car pump perfectly takes the place of a stationary pump. It is also suitable for bicycles, shows, shows exactly how many atmospheres are pumped up, and does not take up additional space. Some people prefer to pump up on professional pumps at gas stations, but the absence of their own professional tool can play a bad joke in the event of an unexpected situation or when you deviate from the standard route.

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How riding style and tire pressure depend.

When a cyclist trains on relatively flat asphalt roads, country and forest dirt roads and paths. For this style of riding, I prefer to pump the wheels up to 3.5-4 atmospheres. Such a high bar value allows you to achieve good speed characteristics, high rolling, but when it hits bumps and stones, the fifth point immediately feels all the unevenness of the road surface.

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For those who like walking at low speed on the flat roads of parks, 2.5-3 atmospheres will be enough. On the Internet, you can often find recommendations to pump 2-2.5 bar into wheels, this is justified only for tires at least 2 inches wide and subject to driving over rough terrain or poor coverage. Low pressure increases traction and comfort, but reduces roll on flat pavement. You should not ride at a pressure less than 2 atmospheres under any circumstances.

The choice of the terrain, on which you prefer to ride, obliges you to choose a certain type of tire, but in general, if you have a universal tread, you can make your ride comfortable on a particular type of road surface by changing the amount of atmospheres on the wheels. The figures below are based on a standard 2-2.1 ″ tire.

For gravel, mud, grass, sandy surface, it is better to pump up to 2.5 atmospheres, which increases the adhesion of the tread to the ground and allows the wheel to smooth out all the irregularities of the road surface well enough.

For flat asphalt tracks, feel free to use a pressure of 3 bar or more. However, there is one but. If you have a fairly bald tread (wheels with a weak relief or slick tires), and you are driving at high speed on wet or even wet asphalt, then you risk slipping (flying out) when cornering. If it rains on the road, just slow down or slightly deflate the tires.

This article describes the most acceptable criteria for choosing tire pressure, but since each person independently selects the most convenient pressure values, I advise, first of all, when mastering a bicycle, experiment.

Standard pressure

Here are some tables that will help you navigate in difficult situations, namely:

  • an unknown tire without markings was purchased;
  • no physical access to the bike;
  • the marking is incomprehensible, the numbers are marked in unknown units.

Mountain bike table:

For a road bike, the pressure should be much higher, and typically ranges between 6.5. 9 atmospheres (up to 130 Psi), up to the maximum indicated by the manufacturer.

Weight changes

For heavy riders or heavily loaded bikes, it is very important to add pressure, as a lot of mass will squeeze the wheel of the bike and problems with insufficiently inflated cameras can come out much earlier.

Recommended pressure for weight addition is 1% for every kilogram of rider weight over 50.

Why it’s important to inflate your tires with the correct pressure

Let’s start with the very basics, here’s a bike going down the road:

  • The more inflated the tires, the better it rolls, the less fatigue
  • The heavier the cyclist, the more you need to pump
  • The more the tires are inflated, the more it shakes on bumps
  • If the pressure is weak, then moving over the curb, you can punch the chamber on the edges of the rim (snake bite)

And now the logical question is how to find out within what framework you need to pump, how many atmospheres to pump specifically? The pressure in bicycle tires is measured in atmospheres (BAR) or PSI, and most often, the permissible range is written on the sidewall of the tire in PSI (one atmosphere is equal to 14.7 psi). Here is the average table for the average cyclist riding no extreme, on asphalt and dirt roads.

This information is enough for you to ride comfortably enough, while the tires will not suffer from over-pumping or under-inflation. Well, for those who care about details, we go deeper.

Road bike tire pressure

With bikes for asphalt roads, everything is simple. the more pressure, the better the roll. Look on the sidewall of the tire, there must be written a valid value, in psi, or in bar (atmosphere). If the maximum value, for example, 8 Bar, then score 7.5 and enjoy the speed.

I highly recommend getting a good floor pump with a pressure gauge (I bought it here), because pumping up a road tire with a portable pump is still a torment, even if it is capable of delivering high pressure.

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. You can’t feel it with your fingers, so a floor pump with a pressure gauge is just the right thing to do.

If you inflate a road tire below average, you can catch a tube breakdown called a snakebite. This happens when the wheel hits a hard object and the tire hits the rim. The result is two small holes that look like a snake bite.

Mountain bike tire pressures

Off-road bikes are a little more complicated. The point is, here you need to strike a balance between grip and coast. The more inflated the tire, the better it rolls (on a flat and hard surface), but due to the rigidity it cannot lick the surface. the grip deteriorates.

High pressure maintains the semi-circular profile of the tire, while maximum grip is possible when the full contact patch is involved. In other words, the more the tire flattens, the better for flotation and handling. On the other hand, if you pump too weakly, the roll will suffer and the same snake bite is possible.

Since basically all chamber mtb rubber has an allowable pressure range of about 2-4 atm, then I would say that the working pressure is between 2.2 and 3 atmospheres for an adult man weighing from 75 to 90 kg. It is impossible to say more precisely. there are a lot of factors, you need to experiment with a specific tire and a specific trail where you ride.

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Different tires behave 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 pressure limit at which the tire still does not break. Then try how the bike rolls at that pressure. Add air if needed. You need to find a middle ground for both soil and asphalt.

How much pressure should be in bicycle tires

It would seem that it could be simpler. pumped up, crumpled with fingers, drove off. But no, there are some subtleties here. Tire pressure is the most important factor in rolling, floatation and bike handling.

I am not deliberately touching tubeless tires yet, because they are installed on more expensive bikes, and this is a topic for a separate article.

Fatbike tire pressure

The fat bike is designed to ride on loose surfaces, its huge, large-volume tires must flatten over bumps, this is achieved by low pressure.

Fat is the perfect bike for winter, so let’s talk about riding in the snow. For a rider weighing 80kg, the following figures may be acceptable:

10psi Rolled snow, paths
8psi Thick snow
6psi and below Loose snow

Fat rolls much better on loose snow if you pump less than 5psi. But reducing the pressure below this line for tube tires can be a bad decision. the bike starts to obey the steering wheel poorly, swim, the nipple can break or shear due to cranking the tube. Therefore, I recommend switching to tubeless wheels for your fat bike, the bike will roll better and more stable at extremely low pressure.

In addition, do not forget about 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 went out to frost of 10 degrees, it became 4.3. Here is a table by which you can calculate the approximate dependence on temperature:

The pressure in the chambers depending on the outside temperature
Indoor temperature, ° C Outside air temperature, ° C
25 10 five -five -10 -fifteen -twenty
740 Atmospheric pressure, mm Hg
psi at room temp. psi outdoors depending on temperature
four 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
five 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
eight 6.8 6.4 6.0 5.6 5.1 4.7 4.3
nine 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 a half slick, the low pressure negates its benefits. The meaning of the semi-slick is that, thanks to the semicircular profile, the tire rolls on a hard surface with a smooth part of the tread. And only after hitting soft ground, the side part of the tread comes into play.

And if the tire is poorly inflated, then it will be flattened, and your half-slick will paddle with its lugs even on the asphalt. Therefore, in this type of tire we pump close to the maximum pressure.

Standard 2.1-2.3 inch cross country tires require a working pressure of 3-4 bar. Such rubber has not very pronounced lugs, it is the most versatile tire for those who ride in forests.

Tires for more extreme riding are 2.3 “wide and wider, 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 it must be borne in mind that in the cold, the pressure drops a little, so at home pump it about 20% above normal so that everything on the street comes into balance.

Here I described how to choose the right bike tires for different riding styles, I advise you to look.

I would not want readers to imagine a picture of a cyclist with a pump, which only does what sets different pressure under different conditions.

In fact, finding a middle ground is quite simple, you just need to devote half an hour. I advise you to pay attention to this issue, if you are a beginner, then most likely you have not even thought about it.

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Yes, the right pressure is very important. As recently as yesterday before leaving, I did not check it, I went. As I said, I have a MAXXIS Larsen TT, and it has very soft sidewalls. I feel that the rear wheel is driving at cornering speed. Drove on the road to a tire service to check the pressure. I usually ride at 3.5-4 atm, but here it is only 2.5 atm. That immediately unpleasant sensations that the wheel will break off or the tire will break.

An expensive pump with a monometer for MTB in our time is superfluous. At any, or almost any, gas station, you can pump the required pressure. And for minor repairs, a mini-pump from the same tea house is enough, fill 3 and get to the gas station.

I do not agree that the floor pump is superfluous. It is not always possible to get to the gas station or it is not so close to check the pressure and pump up the wheel. And you don’t have to buy an expensive pump. Accidentally in Decathlon I got on a sale and bought an excellent floor pump there for 500r. With a long hose, high, not very thick working chamber, which makes it easy to pump high pressures, aluminum body and footrest, which are rare in cheap options

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I like more pressure. I swing 4 atm before, 4.2 back. Kenda rubber 8 small blocks 2.3 ″ (:)), I weigh 87-89kg, I drive both on the ground and on asphalt. Rows normally on mud, but sand is death. Immediately I burrow (well, it is understandable :)) So I shake so that the rubber does not play on turns, but it is bouncing and rolls on pebbles, but very precise control. At high speed (50-70 km / h) it is very noticeable. Then, and at a lower speed, I began to notice this effect. Well, he began to pump in the area of ​​maximum pressure. By the way, with intensive pedaling, the pumped rubber does not start to swing.

This is where you accelerated to 70 km? Not a rope behind the car? Or when he was dropping off the balcony?

maybe he has a gravel bike. Ie shoser with spike. that can roll 50-70. ON MTB, yes, behind a truck only or from a hill, or on a cigarette standing next to a bike

A floor pump is a thing! I recently bought myself, with a large working chamber, a pressure gauge. Because There are several bicycles in the family, and on mine there are also several sets of rubber, which I change depending on the type of coating, it saves time and effort perfectly, plus on different bikes there are also different types of nipples, but here there are two separate heads. do not twist anything it is necessary, conveniently, in general By pressure, I concluded that I pump the toothed rubber of Richie to 3.5 and it is nice, soft and tenacious, though not very fast, and I pump Marathon Supreme slicks up to 5 atm, on asphalt it’s a fairy tale, although recently I I have already begun to poke into the ground in them because the slicks are high 622 × 50 But with my wife’s bike it is more and more difficult, it is much lighter than and here I do not know whether the rubber is to blame or the fork, she complains that she was driving like on sand, even on asphalt, the descent of the rubber saves a little, but only a little.

Abysmal, with MAXXIS, these are known problems. in the sense of soft sidewalls and insufficient pressure. I have more experience with MAXXIS Overdrive, now here is Gipsy, but the story is the same. As tires they are good. tenacious, do not slip even on wet and dirty asphalt, even though they are slicks. But they cut through the sides when under-pumping and overloading. To prevent them from being driven like that, it is advisable to select a width suitable for the rim, and not set, say, 2 inches per 18 mm rim landing width. Even the stock Specialized is guilty of this. That is why I prefer Schwalbe CX Comp or Road Runner from semi-slick tires. because these are mass tires, they are produced in a wide variety of widths, and it is not difficult to choose the width for the rim (remove drift). Of course, no one canceled the correct pumping

Sergey K, I didn’t want to write about this directly in the article, but I also had problems with Maksis. Exactly what you say. Therefore, I cannot recommend them to readers.

Sergey, so if he drives, on the asphalt, is it on the contrary, underpumping? Or what is meant by drives?

chiba, will be. simislik, but manufacturers do not always indicate this explicitly. So it’s better to look with your eyes.

Abysmal, I also cannot imagine life without a floor house pump.

It is unlikely that it is under-pumping, because pumped up to 4 and gradually lowered to 2, as the descent it drives less, but the roll-off falls. Based on her description, it’s like riding on ice. I really sin more and more on the fork, the bike has already been 3 or 4 years old, and before this season it was used very little, now something happened to the fork. it just bounces back if you squeeze it, in general, if you press the handlebar and release that front wheel will jump, and if you lift the wheel into the air and throw it, then the lead will jump, the fork there is a simple SR XCT, i.e. a fork-simulator, but on mine, too, an extremely simple RS XC28, everything is completely different (it does not jump). I’m thinking, maybe this elastomer has broken (it happens at all or not, I don’t know) or stretched out so it just dangles inside.

if you press the steering wheel and release, then the front wheel will jump, and if you lift the wheel into the air and throw it, then the led will jump, the fork there is a simple SR XCT. the damper cartridge in the right leg has died. Nitrogen left from the chamber or glass oil, or both. This is only to replace the entire plug. There are no spare parts for this, and the cartridge is non-separable and maintenance-free