How to Calculate the Conversion of Pressure Measurements

Keeping the tires of our motorcycle with the right pressure is essential to ride safely. Riding with damaged tires is one of the main causes of accidents, so it is important to know how to take good care of our tires and keep them in good condition while riding. Today we are going to talk about tire pressure, what it is, what it affects, and above all, how to understand the different ways of measuring it in order to always keep it at the correct level.

The pressure in the tire is the result of enclosing a certain amount of air in the space available for it, that is, an inner tube in the case of tires that have one (TT or tube-type tires) or in the space between tire and rim if they do not have an inner tube (TL or tubeless tires).

When the pressure increases, the air particles hit the inner walls of the rubber because they have less space, and this is what causes the tire to swell. However, when temperatures vary, this process becomes more complex. Air, like all gases, changes as a function of temperature, expanding when hot and contracting when cold. If we extrapolate this to what we are interested in, the motorcycle, it leads us to the need to measure the pressure of our tires well, frequently, and very attentive to the manufacturer’s recommendations.

Equivalences between PSI, BAR and kPa

There are several units to measure the pressure of our tires. Although the most common is the PSI (pounds per square inch), it can also be common to find the BARS (BAR) and kPa (kilopascals). This will depend mainly on the manufacturer of the motorcycle, which is who will indicate the recommended pressure, so it is important to know the three, know how to interpret them and know how to switch from one to another correctly. Here is an example of what you can find:

Example of a KTM user book


  • 1 PSI = 0,06895 BAR and 6,8948 kPa
  • 1 BAR = 14,50377 PSI and 100 kPa
  • 1 kPa =  0,01 BAR and 0,145038 PSI

Moving on to practice, we will give an example imagining that the user’s manual of our motorcycle indicates the recommended pressure in PSI, but we have to measure in BAR. If the user’s manual indicates that the recommended pressure is 29 PSI, we must multiply this amount by 0.06895, i.e. 29×0.06895=2. Therefore, the pressure of our tire should be 2 BAR.

It is very important to take these measurements into account, since it is possible that at the gas station or in our own pressure gauge there is only one unit of measurement.

Another option is to use an online calculator that can be found in any internet search engine, but it is important to confirm the result by comparing it with other online calculators. In this way we will be sure that the result is correct.

Finally, we could not finish without reminding you that it is essential to regularly check the pressure of our motorcycle tires. Obviously, this depends on the use we give to the bike, but we should try to do it every two weeks at the most. And always, always, follow the motorcycle manufacturer’s recommendations and inflate the tires to the pressure indicated in the user’s manual, whether it is BAR, PSI or kPa.