How much pressure in a bicycle tire is pumped

Calculation of the recommended value

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How to measure pressure

Air pressure in bike tires is measured in Atmospheres, Bars, Psi and Kilopascals.
The atmosphere is used in Russia. It is almost equal in size to Bar, so in practice these units are interchangeable. 1 atm. = 1 kgs / 1 cm. Sq. = 1.02 bar.
European brands often use Psi in the accompanying documentation for their cycling equipment. 1 psi = 1 psi.
When marking tires, Kilopascals may be used to indicate the minimum and maximum permitted pressures.

In practice, units of measurement are converted to one another using the formulas:

  • 1 psi = 0.068 atm
  • 1 atm = 14.696 psi
  • 1 atm = 101.348 kPa
  • 1 bar = 0.98 atm

You can also use ready-made tables of basic values:

Technical atmosphere (at or at) = kgf / cm2(BAR), bar(PSI) Pound-force per square inch(ATM), physical atmospherekPa (kPa), kiloPascal
Technical atmosphere (at or at) = kgf / cm20.98066514,2230.9678498,066
(BAR), bar1.019714,5040.98692one hundred
(PSI) Pound-force per square inch0.0703070.0689480.0680466.894745
(ATM), physical atmosphere1.0331.0132514,696101,348

Tire care and repair to drive longer

Bicycle tires last a long time. Over time, a tire wears out due to tread wear. In order for tires to last a long time, you need to properly operate and store them. With a reduced pressure in the tire, destruction occurs, small cracks appear, the bending of the sidewall is deformed.

All this leads to faster tire wear. Uneven tread wear is affected by harsh braking. And it is also possible to shift along the rim during braking and rupture of the chamber in the region of the nipple. To avoid this, try to brake smoothly without sudden stops.

In case of mechanical damage to tires, a repair kit will help you. You should always have it with you because you do not know where trouble will overtake. With a little skill, you can quickly and easily repair the puncture site and continue on your way.

Tire type

Slick tires with a smooth semicircular tread surface are designed for driving on dry asphalt, give good roll, speed and require pressure close to the upper permissible limit.

Semi-slick. with a smooth center section and small spikes along the edges of the tread. a versatile rubber for most situations. Good roll-off and speed are maintained, the ability to drive on wet road surfaces and unpaved roads of varying degrees of difficulty is added. The pressure close to the maximum must be adjusted depending on the hardness of the road surface, ambient temperature, human weight.

XC tires are good for riding through forests and rough terrain. They are pumped up to an average 3-4 atmospheres.

Cycle tires with grousers need to spend more time in order to experimentally select personal pressure parameters. You need to focus on values ​​that are high enough to provide the best grip on loose soils.

Important! In addition to the smoothness or “toothiness” of the tread, the width of the tire is also taken into account. The feedback rule applies here. the smaller the width, the greater the pressure. And vice versa. the larger the width, the lower the pumping rate.

To find the optimal tire pressure for your bike, you can consult our tables.

Why it is necessary to monitor tire pressure, and what leads to improper use

When choosing the individual parameters of the pressure in the tires of your bike, you should take into account the various nuances that may arise with excessive or insufficient inflation of the wheels for different types of bicycles. We systematize the features of operation for both options.

Bicycle tire pressures who benefit from this article

The degree of inflation of the wheels of bicycle equipment depends on the type of tires, the bicycle, the weather season, the characteristics of the road surface, the weight of the cyclist himself and the manner of his riding. For a beginner, it is quite difficult to understand the intricacies of air pressure regulation in a bicycle rubber on your own. And this must be done, because the comfort and safety of riding, as well as budget savings, depend on the correct pressure in the bicycle tires.

Let’s consider, in order, the main questions related to the selection of the individual optimal pressure in the bicycle tires.

Additional tips for choosing the right pressure:

When choosing the right tire pressure for your bike, you should also pay attention to factors such as:

  • The surface you are rolling on. So, when driving on rough terrain, soil or sand, it is enough to inflate the tires just above the minimum value, so the grip will be better. When driving on asphalt and flat surface, it is better to choose a value close to the maximum. this will improve the roll forward.
  • Your bike type. We recommend using different pressures depending on the type of your bike. For a mountain bike, this value should be lower than for a sports road bike, for example. The principle here is that the narrower the tire, the higher the pressure in it should be. And vice versa.
  • Outside temperature. In the heat, it is better not to pump the wheels to the maximum, because the air in the chamber heats up and the pressure rises additionally. And in winter, even when riding on snow, the pressure should not be lower than average in order to achieve maximum grip of the tread.
  • User weight. Inflate the wheels more if you are heavy or carry heavy loads on your bike.
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To summarize, it should be noted that there are no hard and fast rules for how many atmospheres should be in your wheels. And the right answer will be your accumulated experience.!

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. 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 “roll-over”. 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 on 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.

How much is the pressure in the tires of the bike

Mountain Bike Tire

Not so long ago such a story happened in my life. Seeing that I was pumping up the wheels of a bicycle, a boy of 10–12 years old drove up to me and asked me to swing the wheels on his bike. As someone who cannot refuse such a simple matter, I connected the pump to his rear wheel. But not having time to do even 20 pitching, we saw with horror how cracks went along the tire and it burst, unable to withstand the internal pressure of the chamber.

As it turned out, this topic is quite extensive and correctly inflated wheels will give the bike better handling and cross-country ability.

BIKE TIRE PRESSURE WHAT SHOULD BE AND WHAT TO RUN?

Every bike lover is obliged to monitor the condition of his two-wheeled horse. It is from this that its service life and ride comfort will envy. When you go on your next trip, do not forget to measure your tire pressure. This procedure is mandatory, because the comfort while driving directly depends on it.

Oddly enough, first of all, the quality of cycling, especially on asphalt, depends on the pressure in the wheels of the bike. Under-inflated wheels easily break through and dampen a large percentage of the cyclist’s efforts, while over-inflated wheels can damage the camera and lead to its rapid wear. Accurate knowledge and experience of riding will help you find the middle ground.

Many are accustomed to checking tire pressure using the old-fashioned method with their fingers. However, this method is very imprecise, and the concept of a “well-inflated wheel” can be very different for every cyclist. That is why it is better to always have a pressure gauge on hand to accurately determine the tire pressure.

What is written on the tires

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

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

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

Markings

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.

How is blood pressure measured?

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 measurement in “atmospheres”;
  • Pa. pascal.

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

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 has something in common with the “atmosphere”, which is quite convenient for measurements.

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

Fat Bike Tire Pressure 101 | Fat Bike Asinine

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

What should be the pressure in the tires of the bicycle?

Oddly enough, first of all, the quality of cycling, especially on asphalt, depends on the pressure in the wheels of the bike. Under-inflated wheels easily break through and dampen a large percentage of the cyclist’s efforts, while over-inflated wheels can damage the camera and lead to its rapid wear. Accurate knowledge and experience of riding will help you find the middle ground.

Markings

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.

Tires and high lugs

All toothed tires designed for travel on soft ground, sand, snow are best used with high pressure. In this case, the grip will be maximum.

Seasonal changes

Seasonal adjustments are quite serious, mainly related to mountain bikes. In the summer, you should slightly underestimate the pumping and not rest on the maximum. Hot asphalt also heats up the air inside the chamber, which increases the volume and therefore the pressure. Also, a pumped-over tire wears out very quickly.

In winter, you should sometimes slightly exceed the maximum in order to achieve maximum work from the tread, especially if the rubber is selected with spikes.

How to check chamber pressure.

Honestly. without a pressure gauge in any way. So you need a bicycle pump with a pressure gauge, a separate pressure gauge connected to the nipple, or you will have to pump up the tires at the service station. they always have something to measure the pressure in the wheels. You need to be careful with the service station. There are times when a valiant worker, forgetting about pressure, hits the wheel with everything he can and the camera and the tire explode in a matter of seconds.

There is one piece of advice. When you know exactly what pressure is now, try squeezing the tire with your fingers. So gradually you will learn to determine the approximate pressure in the chamber by tactile sensations. Remember that already from two bars (atmospheres), the tire feels quite tight to the touch.

If the pressure is low, then the tire can easily break through. In addition, under-inflated wheels extinguish a large percentage of the cyclist’s efforts to accelerate and actually ride. The tire “spreads” on the asphalt and, moreover, is very quickly erased from high friction on it.

This also leads to the so-called “snake bites”. two adjacent breakdowns. Occurs when a sharp run over a curb, stone or bump. In this case, the tire is pressed against the rim, the chamber is clamped between the rim and the object that the wheel has hit, and breaks through in two places at once.

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Riding at low pressure can be dangerous for the rims, you can easily get a figure eight on the wheel. At low pressure, frequent punctures are possible, and when cornering, the tire can generally fly off the wheel, which is already life-threatening.

over, if the wheel is heavily pumped, then it can easily puncture the rim (from the side of the spokes). To protect the camera from this, use a special rim tape. This is a rubber or polymer strip that fits over the rim to prevent the spokes and sharp edges of the spoke holes from punching the tube. So a middle ground is needed. A sample of such a tape is shown in the figure on the right.

It is generally recommended to check the pressure before each ride (at least by touch). Remember that the nipple is not the only poison. The air etches a little through the rubber itself, albeit slowly. Because of this, every month, an inflated tire itself loses an average of one bar of pressure.

I would like to note one more point. When driving, the main load is on the rear wheel, while the front wheel is not so heavily loaded. Based on this, the pressure in the rear tire can be slightly higher than in the front. On average, about 10%.

Approximate values ​​by type of rubber

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

Classic cross-country treads with a width of 2-2.3 inches inflate to 3-4 BAR, depending on the track and habit, a lower value will make riding a strength training, and higher values ​​are simply not allowed by manufacturers, as they lead to a real “explosion” when peak load.

Extreme tires, whether downhill 2.3 wide tricky treads or BMX stunt models should be inflated medium, between high and low to have sufficient traction, and then subtly varied for each trick or downhill.

Bike Tech Tips: Be a Human Pressure Gauge

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.
fifty2.38-2.5935-38632.52-2.7237-40772.72-2.9340-43912.86-3.0642-451053.06-3.2745-481183.2-3.447-50

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.

What to pump up

Bicycle luggage requires maintenance and pumping very often. Even on the most “hardy” 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 bikes, 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:

  • 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 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 lack of their professional tool can play a bad joke in the event of an unexpected situation or when you deviate from the standard route.