Direct 18" vs. 20" wheel comparison for efficiency

[mpgxsvcd]

I have a 25 mile loop that I do controlled efficiency testing on. I have done extensive testing with the 20" Uberturbine wheels and the stock Pirelli PZ4 tires vs. the 18" T Sportline wheels I have but that was always with different tires. Yesterday, I was finally able to test 18" wheels vs. 20" wheels with the exact same model tire and equivalent tire dimensions on the same car.

I did the test with the 18x8.5 T Sportline TS5 wheels and the 235/45/18 Hankook iON EVO AS tires. Then I also was able to do the same test with the new 20x9.0 T Sportline TSA-5 wheels and the 235/35/20 Hankook iON EVO AS tires. Both wheels, tires, and TPMS sensors weighed 46.8 lbs. The 20 inch wheels weigh a lb or two more than the 18" wheels but the 20" tires are a lb or two lighter than the 18" tires. That makes both of them have the exact same combined weight.

My 18" tires had about 3,000 miles on them while the 20" tires had about 3 miles on them.

I test the 20" wheels twice because you can run them with or without Aero inserts. I wanted to see how much of a difference the Aero covers made too.

Here are my results:

1. 18" TS5 wheels = 199 wh/mi @ 59.9 mph average speed.

2. 20" TSA-5 wheels without Aero inserts = 222 wh/mi @ 59.9 mph average speed.

3. 20" TSA-5 wheels with Aero inserts = 194 wh/mi @ 59.9 mph average speed.

As you can see the 20" wheels were significantly less efficient even with the same tires but without the Aero inserts. Once I put the Aero inserts in I was able to achieve my second best efficiency in this test ever. My best efficiency in the test ever was 191 wh/mi with a 2022 Model 3 RWD on very worn stock 18" Michelin efficiency tires with the Aero hubcaps. Getting within 3 wh/mi of that result with 20" wheels on a Model 3 Performance is outstanding.

These Hankook iON EVO AS tires are the real deal for efficiency. They are light years better than anything else I have tested.

For reference the 20" Uberturbine wheels and PZ4 tires did 247 wh/mi at 59.9 mph average speed.

 

[DrChaos]

This is consistent with an academic test I saw. In a nutshell, the aero efficiency was strongly correlated with how much of the overall wheel + tire area was covered (better) vs uncovered (worse).

So when people compare 18" to 20" tires the main difference in efficiency is because in an 18" wheel, of course 100% of the tire area is covered. For aero its not about the tire, it's about the wheel. For tire it's the internal construction and materials on rolling resistance which is a consideration at lower speed efficiency.

So yes, a totally covered "pizza dish" wheel is the most efficient---like that on the early BMW i3. And people hate them. And it's not good for brake cooling.

For whatever reason the fashion in looks is to largest diameter and most open wheels, which of course is worst for efficiency and ride quality. It's really frustrating when manufacturers put all their top of the line EVs to be forced to have less efficient larger wheels.

Can't get top BMW i4 or Tesla 3P or Hyundai/Kia upper or perf models in the lower wheel sizes available otherwise.

 

[mpgxsvcd]

This is consistent with an academic test I saw. In a nutshell, the aero efficiency was strongly correlated with how much of the overall wheel + tire area was covered (better) vs uncovered (worse).

So when people compare 18" to 20" tires the main difference in efficiency is because in an 18" wheel, of course 100% of the tire area is covered. For aero its not about the tire, it's about the wheel. For tire it's the internal construction and materials on rolling resistance which is a consideration at lower speed efficiency.

So yes, a totally covered "pizza dish" wheel is the most efficient---like that on the early BMW i3. And people hate them. And it's not good for brake cooling.

For whatever reason the fashion in looks is to largest diameter and most open wheels, which of course is worst for efficiency and ride quality. It's really frustrating when manufacturers put all their top of the line EVs to be forced to have less efficient larger wheels.

Can't get top BMW i4 or Tesla 3P or Hyundai/Kia upper or perf models in the lower wheel sizes available otherwise.

I definitely noticed a ride quality difference between the 18" T Sportline Wheels and the 20" T Sportline Wheels. It really is jarring with the 20" wheels but they look so great and they really are incredibly efficient.

The 18" open faced wheels are a good compromise. They can't quite match the 20" Aero wheels in efficiency but their efficiency is still outstanding. However, the improved ride quality, road hazard protection, lower cost tires, and better brake cooling properties make the 18s still an outstanding value. I am having a hard time deciding which set I will sell with the old Model 3 when it is time to sell it.

 

[DrChaos]

I definitely noticed a ride quality difference between the 18" T Sportline Wheels and the 20" T Sportline Wheels. It really is jarring with the 20" wheels but they look so great and they really are incredibly efficient.

The 18" open faced wheels are a good compromise. They can't quite match the 20" Aero wheels in efficiency but their efficiency is still outstanding. However, the improved ride quality, road hazard protection, lower cost tires, and better brake cooling properties make the 18s still an outstanding value. I am having a hard time deciding which set I will sell with the old Model 3 when it is time to sell it.

I really want a "Touring" version of the 3P--- comfort tires and wheels with all the other upgrades.

I now understand why the oldies used to get Buicks. Dad has old Benz sedans. Maybe I'm turning into them.

 

[mpgxsvcd]

I really want a "Touring" version of the 3P--- comfort tires and wheels with all the other upgrades.

I now understand why the oldies used to get Buicks. Dad has old Benz sedans. Maybe I'm turning into them.

That is my goal as well. I need to be able to make a 330 mile round trip without charging but I also want to be able to track the car and get max performance. I think having a set of Aero wheels with the Hankook tires will give me the range I need especially with a zero degradation car and then the stock wheels and tires should be sufficient for the track especially if I don't daily drive on them.

 

[milesr3]

I need to be able to make a 330 mile round trip without charging but I also want to be able to track the car and get max performance.

Coincidentally I just completed a 4-day trip with Hankook iON evo summer tyres on Überturbines. I did 276 miles on 62kWh (83% battery).

Over the last 830 miles on Hankooks I’ve averaged 225Wh/mi.

 

[gottagofast]

I wonder how the stock uber wheels would have done compared to your 3rd party wheels

Closer to the aero covers or closer to without aero covers

 

[sdiver68]

I really want a "Touring" version of the 3P--- comfort tires and wheels with all the other upgrades.

I now understand why the oldies used to get Buicks. Dad has old Benz sedans. Maybe I'm turning into them.

Something different from an M3P with aftermarket 18" wheels and touring tires?

 

[Lindenwood]

Super helpful comparison! Making me rethink my daily 285s…. (Very Slightly ).

 

[dsgerbc]

them while the 20" tires had about 3 miles on them.

Retest at 200-300 miles or later if you want your results to mean anything.
New unscrubbed tires overstate efficiency.

I once observed like <250Wh/mile on new unscrubbed RT660s (200 treadwear tire) on the way to an autocross event, and like 350 on the way back.
Regular tires won't have as big of a difference, but it will likely be enough to matter.

 

[gottagofast]

Retest at 200-300 miles or later if you want your results to mean anything.
New unscrubbed tires overstate efficiency.

I once observed like <250Wh/mile on new unscrubbed RT660s (200 treadwear tire) on the way to an autocross event, and like 350 on the way back.
Regular tires won't have as big of a difference, but it will likely be enough to matter.

My model 3 tires efficiency have improved with more use, pilot sport summer tires

 

[mpgxsvcd]

Retest at 200-300 miles or later if you want your results to mean anything.
New unscrubbed tires overstate efficiency.

I once observed like <250Wh/mile on new unscrubbed RT660s (200 treadwear tire) on the way to an autocross event, and like 350 on the way back.
Regular tires won't have as big of a difference, but it will likely be enough to matter.

Efficiency improves with wear. I have always got my worst efficiency with brand new tires.

 

[dsgerbc]

Efficiency improves with wear. I have always got my worst efficiency with brand new tires.

I guess you're right in general. Looked through a book I had bookmarked (page 500). Maybe the super-soft rubber is somewhat different, since I've now observed suspiciously low energy consumption on brand spanking new autox tires for the first 20-30 miles at least twice now.

 

[Clarinette]

I have a 25 mile loop that I do controlled efficiency testing on. I have done extensive testing with the 20" Uberturbine wheels and the stock Pirelli PZ4 tires vs. the 18" T Sportline wheels I have but that was always with different tires. Yesterday, I was finally able to test 18" wheels vs. 20" wheels with the exact same model tire and equivalent tire dimensions on the same car.

I did the test with the 18x8.5 T Sportline TS5 wheels and the 235/45/18 Hankook iON EVO AS tires. Then I also was able to do the same test with the new 20x9.0 T Sportline TSA-5 wheels and the 235/35/20 Hankook iON EVO AS tires. Both wheels, tires, and TPMS sensors weighed 46.8 lbs. The 20 inch wheels weigh a lb or two more than the 18" wheels but the 20" tires are a lb or two lighter than the 18" tires. That makes both of them have the exact same combined weight.

My 18" tires had about 3,000 miles on them while the 20" tires had about 3 miles on them.

I test the 20" wheels twice because you can run them with or without Aero inserts. I wanted to see how much of a difference the Aero covers made too.

Here are my results:

1. 18" TS5 wheels = 199 wh/mi @ 59.9 mph average speed.

2. 20" TSA-5 wheels without Aero inserts = 222 wh/mi @ 59.9 mph average speed.

3. 20" TSA-5 wheels with Aero inserts = 194 wh/mi @ 59.9 mph average speed.

As you can see the 20" wheels were significantly less efficient even with the same tires but without the Aero inserts. Once I put the Aero inserts in I was able to achieve my second best efficiency in this test ever. My best efficiency in the test ever was 191 wh/mi with a 2022 Model 3 RWD on very worn stock 18" Michelin efficiency tires with the Aero hubcaps. Getting within 3 wh/mi of that result with 20" wheels on a Model 3 Performance is outstanding.

These Hankook iON EVO AS tires are the real deal for efficiency. They are light years better than anything else I have tested.

For reference the 20" Uberturbine wheels and PZ4 tires did 247 wh/mi at 59.9 mph average speed.

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Hey,

Thanks a lot for this precious information. As I am contemplating replacing my 5-year-old M3P with a new M3, I am debating with myself 1) which car to adopt: the M3LR or the M3P and 2) which set of wheels to adopt.

I feel that I don't necessarily want to get the 20" wheels as they can get damaged easily. So I am wondering about 18 or 19.

- Would it be possible to do a similar test with the Tesla 19" wheels?
- Do you think that the huge range difference between M3LR and M3P (here, WLTP numbers in km, I'm in Europe)

LR 19​	629​
LR 18​	678​
P 20​	528​

is due to the wheels?
- Is it even possible to put 18"or 19" wheels on a M3P? or will the brakes be too big to accommodate them?

Thanks in advance for all the light you can shed on this. I would love to get answers from Tesla, but they tend to be very arrogant and won't bother to respond to me...

 

[mpgxsvcd]

Hey,

Thanks a lot for this precious information. As I am contemplating replacing my 5-year-old M3P with a new M3, I am debating with myself 1) which car to adopt: the M3LR or the M3P and 2) which set of wheels to adopt.

I feel that I don't necessarily want to get the 20" wheels as they can get damaged easily. So I am wondering about 18 or 19.

- Would it be possible to do a similar test with the Tesla 19" wheels?
- Do you think that the huge range difference between M3LR and M3P (here, WLTP numbers in km, I'm in Europe)

LR 19​	629​
LR 18​	678​
P 20​	528​

is due to the wheels?
- Is it even possible to put 18"or 19" wheels on a M3P? or will the brakes be too big to accommodate them?

Thanks in advance for all the light you can shed on this. I would love to get answers from Tesla, but they tend to be very arrogant and won't bother to respond to me...

18” T Sportline wheels among other brands will definitely fit the old Model 3 Performance. However, I am not sure if they will fit the new Model 3 Performance. I will be able to test this when I get mine though.

I don’t have 19s so I can’t test that. If 18s fit then those will typically be more efficient unless the wheel design is not aerodynamic.

 

[Chucko]

I have a 2023 M3P. I ran the OEM tires for about 8000 miles and then had an encounter with a pothole that necessitated a tire change to DWS06+ as that was all that was in stock in my local area at the time. The DWS06+ were noisier and harsher riding than the OEM Pirelli's and after some thought and research I decided to go to 18" wheels (Konig Ampliform 18x8.5 ET35) and corresponding Hankook ION EVO AS tires in order to improve the ride quality and efficiency. I track everything using Teslafi.com so I was able to generate the below information regarding efficiency. The green under status shows the tires currently active on my M3P. My driving style is what I would call "average". I don't hypermile nor do I drive much in a spirited fashion. Most trips are a mix of city/freeway driving of around 15-20 miles.

 

[DrChaos]

Something different from an M3P with aftermarket 18" wheels and touring tires?

Yeah, something $3500 less, and factory tuned for the tires.

 

[MaartenD]

So yes, a totally covered "pizza dish" wheel is the most efficient---like that on the early BMW i3. And people hate them. And it's not good for brake cooling.

The most stylish rims Mercedes ever made were called the gullideckel because they resembled manhole covers.
And is brake cooling an issue with EVs?

 

[danpass]

I was initially disappointed to find that my 2024 MYP came with Hankook ION EVO AS vs Michelin Pilot Sport AS

but those Hankooks are very quiet on the highway.

In 3400 miles I’m at 296 wh/mi (might be 295). A lot of highway miles, did a road trip from FL to NY and back

 

[tivoboy]

Can anyone comment on the HK ION EVO AS for wet performance, or just regular performance.. I’m not talking tracking or track day at LS, but want to have some good grip and water venting capability.

Might just do four new HK since they seem to be measurable higher efficiency, and offload my two rear OEM tires that have 3K miles on them.