How many atmospheres are there in a road bike

How much pressure should a bicycle tire have? (10 to 29 inches)

An important topic for many cyclists, as we often see people riding flat wheels on the streets.

Two factors depend on the air pressure in the tire.

  • How fast will you roll (the more pressure, the faster);
  • How well your rubber will hold the surface (the less pressure, the larger the contact patch and grip).
  • However, if you DO NOT inflate the tire, then when you increase the grip, you also get a better chance of getting a puncture or a situation where the tire “breaks” in a corner and may even be disassembled. True, for the latter situation, you will need to make a lot of effort. Incorrect wear, you will also be accompanied by.
  • If you pump a tire, there is also a greater risk of puncture and improper tire tread wear.

many, atmospheres, there, road

The higher the rider’s weight, the more you should swing. Rough guideline so that when rolling the tire does NOT break through to the rim.

Our pressure recommendations.

Pressure is measured in the following units:

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  • Psi. pound-force per square inch. pound-force per square inch;
  • BAR. bars, usually equated to measurement in atmospheres;
  • Pa. pascal.

We give numbers in atmospheres. If you have a pump with a monometer, there is usually a duplicate scale for pressure in PSI.

  • The pressure in the tires of mountain, city, children’s bicycles is 2. 4 atmospheres;
  • Hybrid (Mountain Type) Tire Pressure. 3-4 atmospheres;
  • Road bike tire pressure. 5-9 atmospheres.

Also on many tires, pressure recommendations can often be found. You can choose your exact pressure figure for different types of soil only as a result of personal tests. Just take the pump with you on the go.

How to check the current pressure?

With experience, you will be able to check the pressure. just squeezing the tire with your fingers, although this is a rough option.

Tips for choosing tires (spoiler of a new article)

Logic for the size of the area of ​​the contact patch with the ground and the speed also works when choosing tires.

  • The wider the tires, the less roll (the way the tire rolls from one pedal rotation) and the better the tire will bite into the pavement.
  • The more developed the tread (high studs), the more grip and, again, less speed.

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.

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.

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.

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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.

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

How much to pump in tires in winter

If you ride a bike in cold weather, then it must be borne in mind that the pressure drops a little in the cold, 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.

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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

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?

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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

Road Bike Tire Pressure Calculator

Description of the method implemented in the calculator Tire pressure (highway).

Calculator. on a separate page, accessible directly from the menu, here.

Abstract considerations about tire pressure. in a separate note. The general conclusion of this note: on a real road with grainy asphalt and all sorts of irregularities and pits, the wheels should not be too inflated.

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It’s about clinchers and the amateur level of highway riding.

Until 2006, the main approach was to pump to the maximum within reasonable limits, because it rolls better and pricks less. 70% of amateurs still adhere to this. In 2006, California amateur Frank Berto discovered that there is a limit beyond which it makes no sense to swing, the roll does not improve. He empirically found that the limit is determined by the tire sagging of 15% under the weight of the equipped bike plus the rider. Frank Berto investigated tires of different widths (in the garage, using a jack) and plotted the dependence of the tire pressure on the weight on the wheel.

Illustration of 15% drop and experimental data by Frank Berto

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The formula aroused doubts (why 15%, etc.), it was rechecked, sometimes the pressure threshold was slightly raised, but on the whole they agreed that it worked. You shouldn’t pump higher, lower. they called it a comfort zone.

The formula does not take into account the width of the rim, the stiffness of the tires and, most importantly, the condition of the road. In addition, it is customary in the network to set the pressure difference between the wheels at 10 psi, and the formula gives 20-30. The formula does not at all take into account the approach of tire manufacturers, who indicate the range of min., Below which the tire loses its properties, mainly anti-puncture, and max., Above which it cannot be pumped. The network mind recommends not paying attention to this. the real minimum is determined by snake bites, the maximum is the strength of the rim walls.

In general, the formula gives an upper limit, above which it makes no sense to swing on real asphalt. Irregularities in the road that go through the tire, any bounce from the road. lead to braking. In general, the very feeling of a good roll-off in a road bike, when the road is felt as a fifth point in all details and it seems that turning the pedals immediately turns into movement is subjective and does not correspond to measurements.

The summation of network and personal experience led to an algorithm that is implemented in the calculator.

From the curb weight and tire width according to the Frank Berto method, the initial data on wheel pressures are determined, based on the weight distribution between the wheels 45/55%.

Add 8 psi to the resulting front wheel pressure.

The resulting values ​​are multiplied by about 0.95 (with a slight inverse relationship. for a lower weight coefficient. more).

The result makes it possible to avoid snake bites, achieve maximum comfort and keep the roll.