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20’s vs 22’s and energy efficiency

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I have been debating for a long time if lightweight 22” rims will be as big a penalty in efficiency as the Tesla turbines. And wider tires vs 245’s

There is a lot of information on this forum stating up to 20% hit.
I came across this article performed by velonews looking at the energy efficiency of bicycle tires. Different widths and inflation pressures.

Their conclusion if I read properly is that a light weight I sprung mass with a low profile wide tire will have the lowest rolling resistance.
Also I came across another article that basically stated that above 40 mph the aerodynamic drag eclipses the rolling resistance, so it might only be a hit if most of your driving is below 40 mph.

(I hope the image uploads)
 
I hope I can answer this question in 6 months time when summer arrives and I swap our current 20s for 22s.

My suspicion is your right on long trips it shouldn't matter that much, but shorter start/stop trips the 22s will show much worse range.

However range only really matter when doing road trips, so the real life impact of worse consumption for short trips is negligible.

I'll do a post on this when I've done my wheel swap and some road trips.
 
So I have both - I use my 22's in the summer and my 20's in the winter.

I have tracked my usage via TeslaFi and to be frank, it is difficult to extract specific conclusions as speed, temperature (heat/AC usage also), elevation changes and other factors all contribute to the #'s.

In winter, on my 20's, I regularly see high 400's/low 500's (heater) on my 20's vs the summer where I will see 300's with my 22's (A/C).

My point is, I really think ultimately the # is negligible when it comes to overall cost for a $150k car. For instance:

May 2018 (20's):

# Of Drives Total Miles Wh/Mile Efficiency kWh Used Avg Temp Total Cost Time Spent Driving
116 1104.64 545 Wh/Mile 58.78 % 602.51 kWh 72.97 F $ 75.34 73 Hours 9 Minutes

vs August (22's)

98 1842.59 406 Wh/Mile 79.08 % 748.48 kWh 84.77 F $ 93.57 37 Hours 51 Minutes

Obviously more highway in August than in May, but MUCH lower on the 22's than the 20's.

Too many factors to extrapolate quality data. Just get the 22's and enjoy - they look much better than the 20's and they handle 10x better too!
 
Technically, I believe the 20” should be slightly more efficient driving stop&go on local roads, and the 22” should be slightly more efficient on the freeway because of rolling momentum.
Is there a noticeable difference in enjoying the car on a everyday basis? I doubt it. Haven’t tested the two myself and so I’m not certain. But, I’m fine with my 22” just the way they are. They just look better.
 
I have been debating for a long time if lightweight 22” rims will be as big a penalty in efficiency as the Tesla turbines. And wider tires vs 245’s

There is a lot of information on this forum stating up to 20% hit.
I came across this article performed by velonews looking at the energy efficiency of bicycle tires. Different widths and inflation pressures.

Their conclusion if I read properly is that a light weight I sprung mass with a low profile wide tire will have the lowest rolling resistance.
Also I came across another article that basically stated that above 40 mph the aerodynamic drag eclipses the rolling resistance, so it might only be a hit if most of your driving is below 40 mph.

(I hope the image uploads)

There's a lot of factors going on here. On the highway, the spacing between a 22" turbine spoke and a 20" turbine spoke is significantly different as well. Most don't realize it, but there is very little space available on a 20" turbine and it acts very much like an aero cover. Thus on local you lose efficiency via unsprung weight; but on the highway you still lose via aerodynmic drag. Not to mention in both situations the tire is stickier and wider; which increases friction.

Lowest I've gotten was a 8% increase on my 22's over my 20's.
 
There's a lot of factors going on here. On the highway, the spacing between a 22" turbine spoke and a 20" turbine spoke is significantly different as well. Most don't realize it, but there is very little space available on a 20" turbine and it acts very much like an aero cover. Thus on local you lose efficiency via unsprung weight; but on the highway you still lose via aerodynmic drag. Not to mention in both situations the tire is stickier and wider; which increases friction.

Lowest I've gotten was a 8% increase on my 22's over my 20's.

So wait-- are you saying that you get *more* efficiency / mileage from 22" wheels?