Bar and psi are tire pressures. Measurement and conversion

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:41

All owners of wheeled vehicles - motorists, motorcyclists and cyclists - have to monitor tire pressure. For each type of transport there is a range of optimal pressures, which, among other things, can be recognized by the marking of rubber.

Most often you have to deal with units of bar or psi. Pressure in inches per square meter (psi) is used to label tires made in England and America. Ba r is a unit for measuring pressure, adopted in European countries, including ours. It is almost equivalent to a technical atmosphere.

Most modern pressure gauges have a dual scale, where you can immediately see the pressure in bar and in psi. There are also electronic pressure gauges for motorists, they select the desired display mode. But you have to do a handwritten conversion of psi to bar and vice versa quite often, since not every motorist has measuring instruments.

For a single calculation, it is enough to use the equality:

1 psi=0.069 bar

1 bar=14.504 psi

Three decimal places of precision is not normally required. In most sourcesyou will find that 1 bar ~ 15 psi. But the higher the pressure, the greater the error in the calculations according to this approximate equality. Therefore, multiplying by 14.5 is the best option.

You can also transfer pressure from bar to psi using special electronic pressure gauges, which are sold in shops for motorists. But if there is no such device, and the conversion of psi units to bar and vice versa needs to be carried out often, it makes sense to make a table. In garages, tables are used with value increments of 1 and 0.1 bar, or from 5 to 15 psi. And if you have access to the Internet, the easiest way to translate the value is with a search engine calculator.

Measurement errors

Tyre pressure is quite dependent on temperature, so the pressure gauge readings will differ in warm and cold seasons, even if the same amount of gas is pumped. The tire also heats up while driving, from friction with the road surface.

Measurements are usually carried out "cold", when the car has traveled no more than 3 km at low speed or has stood for at least 2 hours. When it was not possible to comply with the condition, it is necessary to subtract 0.3 bar ~ 4.5 psi from the readings received. The pressure measured in winter and summer can differ much more: for every 5 degrees Celsius drop in temperature, the reading decreases by 1 psi.

A car or motorcycle tire naturally loses about 1 psi each month (bike tire pressure drops by as much as 15 psi). Thus, with a gradual increaseaverage monthly temperature in the spring, pumping up car tires is often not necessary. And in autumn, and especially with a sharp cold snap, this is a guarantee of safety on the road.

It is sometimes difficult for a non-professional to determine the exact pressure, since an error almost always appears in mechanical devices. Now you can buy pressure gauges with "smart" microcircuits that correct for temperature. Whether it is worth buying a multifunctional device, trusting your intuition or the skill of a service station employee is up to you. The main thing is that the tire pressure is suitable for a comfortable and safe ride.