TyreReviews.com has published data from German magazine, Auto Motor und Sport, test of low RR and UHP tires. It's a comprehensive test of tires we can't buy, but... "The magazine tested the rolling resistance of the tyres, which is a machine test, and the energy consumption in the real world using the Kia EV6." GT-Line trim.
Yippee! That's data we can use!
A direct comparison of machine data and real world data, using the car we all prefer! Data is plotted above for 9 of 10 tires because one of the Falken tires didn't fit. RR units are 1/1000. I extrapolated at the high end because 0.006 is about the lowest RR tire I've seen, while twice that's not uncommon. I also looked at more complex curve fits, but none gave a real R-squared increase.
Bottom line?
0.001 of RR reduction is worth 0.21 mi/kWh of efficiency increase, about 5%.
They included a Continental Kia EV6 GT-line OE tire; its mid-pack at 0.0074. There's 5% to be had!
