The two mile drive
can definitely be enough to increase temperatures, especially if the tires are too low since the additional flexing will cause them to warm up faster.
I'm gonna lay out a theory. It might be complete BS, but I'm out of ideas.
- Tires are at 35psi. You drive to fill them, which warms them to 40psi.
- A mere 2psi is added to give 42psi. You drive away. (effectively now 37 psi cold)
- Temperature has dropped over the course of a week, reducing pressure.
- Tires are at 35psi. You drive to fill them, which warms them to 40psi.
- Another measly 2psi is added to give 42psi. You drive away. (effectively now 37 psi cold)
- Temperature has dropped EVEN MORE over the course of a week, reducing pressure.
- ... you get the idea.
So basically, I'm suggesting this
might be normal seasonal pressure differences and the average temperature fluctuations are lining up in such a way to play games with you, especially since only rather small amounts of air may be added at your fill-ups.
Regarding 42 vs. 45 PSI: I understand this was a change at some point. All used to be 45, now all are 42 (to my understanding). I also stumbled across the fact that XL rated tires (the tires used for the Model 3) are rated to handle their load at a
maximum of 42 psi. This may be why Tesla changed it, especially as they moved into more countries with the Model 3. A higher load rating seems to require moving to light truck (LT) tires. This would be problematic for a few reasons.