Quote:
Originally Posted by Vekke
I did also pressure testing in my electric ID3 at 100km/h speed with 195/55r20 Nokian Hakkapeliitta R2 winter tires. There optimal pressure was not higher than recommended. I found optimal pressure is around 2,5 bar.
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There are diminishing returns above a certain point, but I've never seen a tire have worse rolling resistance at a higher pressure *on a smooth surface.*
One thing to keep in mind is that pumping tires to higher pressure makes them larger. This is quite obvious to see when you go from 5psi to 15psi to 25 psi, but it is much harder to spot going from 40psi to 50psi.
In my testing, I observed no mpg gain going from 40psi to 50psi in my Prius. It wasn't worse, but it wasn't better. But when I marked the tires and measured how far they rolled, I discovered that at 50psi the tires rolled about 1% farther than at 40psi. So my 0mpg gain was actually a hidden 1% gain...
Not mine, but this shows the diminishing returns I've seen from higher psi:
