Last updated: 2024-04-14
How much air in bike tire?
How do I find the right bike tire air pressure?
What is the correct mountain bike tire pressure?
| Recommended tire pressure | ||
| Front tire: | ||
| Rear tire: | ||
The specified tire pressure is only a recommendation, it is based on the tire pressure table below. Adjust it to your driving habits and the road conditions.
For the rear tire, the tire pressure calculator adds 0.2 bar, because with common bicycle geometries there is slightly more load on the rear tire than on the front tire. Depending on the mounting location of the panniers – these are available for the front wheel as well as on the rear wheel – other values may be appropriate in individual cases.
The most important information is the tire pressure range approved by the tire manufacturer. This is usually printed on the tire casing and looks, for example, as follows:
The minimum or maximum tire pressure should not be under- or exceeded. In between, you can choose a tire pressure that is optimal for you; the following recommendations should help.
There are various tables with guideline values for the optimum air pressure on the Internet, fortunately most of them contain quite similar recommendations. The following is a tire pressure table from Wikipedia:
| Tire width | Tire pressure | |
|---|---|---|
| 20 mm | 9.0 bar | 131 psi |
| 23 mm | 8.0 bar | 116 psi |
| 25 mm | 7.0 bar | 102 psi |
| 28 mm | 6.0 bar | 87 psi |
| 32 mm | 5.0 bar | 73 psi |
| 35 mm | 4.5 bar | 65 psi |
| 37 mm | 4.5 bar | 65 psi |
| 40 mm | 4.0 bar | 58 psi |
| 44 mm | 3.5 bar | 51 psi |
| 47 mm | 3.5 bar | 51 psi |
| 50 mm | 3.0 bar | 44 psi |
| 54 mm | 2.5 bar | 36 psi |
| 56 mm | 2.2 bar | 32 psi |
| 60 mm | 2.0 bar | 29 psi |
As you can see nicely in this table, narrow bicycle tires require a high tire pressure and wide bicycle tires require a low tire pressure.
The tire pressure recommendation in the above table refers to 75 kg for the weight of the cyclist including load (items in the bike basket, bike bags, backpack).
For every 1 kg of extra weight, the tire pressure can be increased by about 1 %, and reduced accordingly for less weight.
The surface on which you drive is another important factor influencing the optimum tire pressure. In general, the harder and more uniform the surface, the higher the tire pressure can be. A higher tire pressure reduces the rolling resistance of the bicycle tire on the surface. This reduces the contact area with the ground and the tire has to do less flexing work.
For unpaved gravel, sand and forest tracks a low tire pressure is the better choice. The tire cushions small bumps better. In addition, the tires hug the ground more closely, creating a larger contact area and giving the tire greater traction (grip), as the following graphic illustrates.
In rain, snow and ice, you should also ride with less pressure, as this reduces the risk of slipping away.
The following overview summarizes the advantages of higher or lower tire pressure:
| Low tire pressure | High tire pressure |
|---|---|
|
|
You can find the optimum tire pressure for you by varying the tire pressure a little and taking a test drive each time.
Apart from the above-mentioned effects on ride comfort, the tire pressure should never be too low or too high. The following table gives an overview of the possible problems with incorrect air pressure in the bicycle tire, which will be explained in more detail below:
| Too low tire pressure | Too high tire pressure |
|---|---|
|
|
Underinflation causes increased walk work of the tire, which puts more stress on the tire's sidewalls and causes them to become brittle more quickly. This reduces the lifetime of the tire.
Likewise, bicycle tires with inner tubes can break down if, for example, a curb or a stone is driven over. In the process, the bicycle tube is clamped between the casing and the rim and punched through. Since the tubing is doubled over, this usually creates two side-by-side holes called a snake bite. Strong impacts can even deform the rim and thus damage it.
In curves, too low tire pressure can lead to worse driving stability, because the tire starts to "float", i.e. it moves a bit across the direction of travel. This worsens driving behavior and safety.
If the tire pressure is too low, the tire no longer sits so tightly on the rim that it can move longitudinally, especially when braking. This pulls the tube with it and leads to lateral stress on the air valve firmly screwed into the rim. After some time, this can lead to a crack on the valve or even valve rupture and the tube will leak.
Overinflation of the tire can cause expansion cracks in the rubber and bulge the tire, this reduces the lifetime of the tire.
Also, high tire pressure directly leads to worse damping of bumps, shocks are transmitted more directly to the frame and rider, especially if the bike does not have a suspension fork and rear suspension. The driver perceives this as increased vibrations.
The low elasticity of the bicycle tire at very high tire pressure leads to a small contact area of the tire with the ground, which means a lower grip on both smooth and uneven surfaces.
Above text is generally valid for all types of bicycles, but it is quite technical and explains many details. If you simply want to know the correct tire pressure for a specific bike, the following overview should help you to get a suitable recommendation as uncomplicated as possible.
For driving in the city and on mainly firm ground, 2.5 bar is a good starting point.
On mountain bikes, tire widths of 50 to 64 mm are normally installed, so the recommended tire pressure is in the range of 2 to 3 bar.
If you move on unpaved trails, you should lower the tire pressure a bit to get more grip. With tubeless tires, even lower tire pressures are possible because punctures are less likely to occur.
In the past, the tire width 23 mm was common on the road bike and was pumped up to 8 bar. Meanwhile, tire widths of 28 mm or even 32 mm are frequently seen. A tire pressure of 5 to 6 bar is suitable for these.
Tire widths of 37 to 52 mm are typically used here. The optimum tire pressure is therefore in the range of 2.5 to 4.5 bar and cannot be reduced to a single value.
It is best to use the tire pressure calculator or chart above to determine the correct bicycle air pressure.
For bicycles with electric motor, the correct tire pressure is basically based on the type of bicycle and its tire width, see the types of bicycles mentioned above.
Since e-bikes and pedelecs travel faster and are about 10 kg heavier due to the additional technology, they require about 10 % higher tire pressure. The tire pressure calculator above helps to find the correct tire pressure.
28-inch tires are the most common tire size on adult bicycles. However, since they are used on different types of bicycles (see above), the tire widths can be quite different and thus the correct bicycle tire inflation pressure.
The bicycle tire pressure calculator above helps to find the correct tire pressure.
To inflate the bicycle tires it is recommended to use a bicycle pump with pressure gauge, that is, with an indicator for the tire pressure.
A bicycle tire can lose up to 1 bar of tire pressure per month. Generally speaking, high pressure is lost more quickly than low pressure, i.e. tires with high tire pressure need to be pumped up more often.
So the tire pressure should be checked regularly, especially before longer bike rides.
If you press on the tire tread with your thumb, the tire feels hard from about 2 bar and you easily get the wrong impression that the tire is well inflated. This type of thumb test is therefore unsuitable in practice.
It works somewhat better to compress the bicycle tire on the lateral flanks instead of on top of the casing. Here, a low tire pressure can be detected more easily. However, even this method is not reliable.
In the long run, it is advisable to purchase an air pump with a pressure gauge to be able to determine the tire pressure precisely.
Short answer: No.
Longer answer: Air is a mixture of many different gases, with nitrogen being by far the largest component (about 78 %). A tire filled with pure nitrogen also loses pressure. In practice, therefore, it makes no difference whether a bicycle tire is filled with 100 % or with 78 % nitrogen. So you can safely save the money for a pure nitrogen filling.
