Recently, because of an incident with a friend's car, I started monitoring my tire pressures regularly, and I'd like to understand if the encountered behavior is normal.
I started checking tire pressure daily (through the built-in sensors), on the cold tires, as well as 'hot' (after a 30+ minute fast drive). The daily values are consistent, and slowly lower over time. What I found is that I continually lose some pressure over the months, about identical on each tire.
Question: Is a loss of 1.5 - 2.0 psi per month normal? (that's 0.10 - 0.14 bar)
I am comfortable to pressurize the tires to about 3 psi over the recommended pressure (cold), but not to let them get under the recommended value.
With that, I would need to 'top them off' every three months at least.
Is that normal? Or do I have an issue (in all four tires?)