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Old 11-07-2023, 11:07 AM   #98 (permalink)
bwilson4web
Engineering first
 
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Join Date: Mar 2009
Location: Huntsville, AL
Posts: 843

17 i3-REx - '14 BMW i3-REx
Last 3: 45.67 mpg (US)

Blue Bob's - '19 Tesla Std Rng Plus
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I appreciate the reports you've accumulated. About two years ago, the video author did a YouTube video about EV wheel size vs efficiency:
https://youtu.be/NYvKxsYFqO8?si=Rwh6LX41z47XUgfG&t=382

Here is another analysis with an EV emphasis on efficiency impact:
https://youtu.be/8pM9o2Ifcro?si=oc7e1923zbc2_X1Q

A former bicyclist (1970s), I had direct mechanical input to the size of the tires. Fatter, wider tires required significantly more force to move but they could deal with soft and rough terrain. In contrast, narrow, high-pressure tires, 100 psi, were almost effortless on pavement compared to fatter, wider, lower pressure, 50 psi tires. Even today, my BMW i3 has taller, narrower tires than my Tesla Model 3.

There is a lot of 'tire marketing' versus 'tire testing'. Worse, tire models within a brand can (and do) easily disappear or get changed. That part is maddening.

I monitor both tire pressure and temperature. The temperature seems to correlate with rolling resistance, higher temperature, higher rolling drag.

Speculation, we could put different tires on the non-driven wheels and after alignment, observe temperature on the road at the same tire pressure. The cooler tire would be the more efficient. Get a second, efficient one and the less efficient tire goes into storage, returned, or sold.

Bob Wilson
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2019 Tesla Model 3 Std. Range Plus - 215 mi EV
2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade
Retired engineer, Huntsville, AL
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