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LR MY 19" vs 20" efficiency measured

egaertner

Member
Feb 16, 2019
47
169
San Jose, CA
An often asked question is how do the 20" induction wheels impact efficiency compared to the 19" gemini wheels. I found a handful of anecdotal accounts of people driving long ranges with both wheels to compare, but no well controlled experiments.

To gather some better data I test drove two LR MYs back to back, one with each wheel size, aero caps on the 19". I took them 5 miles up and 5 miles back the same stretch of highway. 70mph autopilot the whole time, no vehicles in front to slow me down or draft behind. Both happened to have 42psi in the tires and 70mi of range left on their batteries at the start. I would have liked to do multiple runs to get a better average but test drive beggars can't be choosers.

19" MY: 335Wh/mi northbound, 251Wh/mi southbound, 293Wh/mi average
20" MY: 328Wh/mi northbound, 263Wh/mi southbound, 295.5Wh/mi average
Less than 1% difference

I also tested my M3 with 18" wheels, aero caps, roof rack, and brand new Pilot Sport All Season 4 tires (known to reduce range) as another datapoint.
18" M3: 315Wh/mi northbound, 269Wh/mi southbound, 292Wh/mi average

My biggest takeaway from this is that I suspect the 19" wheels without aero caps would have worse efficiency than the 20" wheels. There's surely some error in my data, but I doubt it's more than the known efficiency reduction of removing the aero caps.
 

jcanoe

Active Member
Oct 2, 2020
2,089
2,056
Maryland
Your results affirm something I recall reading. The Tesla Model Y 20" Induction wheels are designed for good aerodynamics, efficiency. The weight of the Model Y optional 20" Induction wheel (31.55lbs) is only slightly heavier (1.95lbs) than the Model Y standard 19" wheel (29.6lbs.) Not sure if the specified weight of the 19" wheel includes the Gemini wheel covers.
 
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iustin

Supporting Member
Feb 5, 2020
98
42
Switzerland
This is interesting. The difference is definitely less than what I'd expected.

@jcanoe - if what you say about wheel weight is true, maybe it explains why the 20" wheels also have less towing capacity? This is on page 73 of the current manual: with 4 or more passengers, 19" and 21" wheels support 3500lbs towing, whereas 20" only support 2300lbs (similar for tongue weight). So I'm thinking that bigger wheels at same size means a bit less strength or such?
 

jcanoe

Active Member
Oct 2, 2020
2,089
2,056
Maryland
This is interesting. The difference is definitely less than what I'd expected.

@jcanoe - if what you say about wheel weight is true, maybe it explains why the 20" wheels also have less towing capacity? This is on page 73 of the current manual: with 4 or more passengers, 19" and 21" wheels support 3500lbs towing, whereas 20" only support 2300lbs (similar for tongue weight). So I'm thinking that bigger wheels at same size means a bit less strength or such?
I thought that while it was initially stated in some of the Tesla Model Y documentation that the tow rating with the 20" wheels was less than the tow rating with the 19" wheels or the 21" wheels this was later updated. Now the tow rating (3500 lbs) is the same for all three Tesla wheel sizes. I could be wrong.
 

iustin

Supporting Member
Feb 5, 2020
98
42
Switzerland
I thought that while it was initially stated in some of the Tesla Model Y documentation that the tow rating with the 20" wheels was less than the tow rating with the 19" wheels or the 21" wheels this was later updated. Now the tow rating (3500 lbs) is the same for all three Tesla wheel sizes. I could be wrong.

I've just downloaded the manual and the quote I gave is from page 73 there. The difference is only with 4 persons or more, which is strange (shouldn't weight matter more than number of people?) For 3 people, yes it's all the same.
 

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