LR MY 19" vs 20" efficiency measured

[egaertner]

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.

 

[patnshan]

Thanks for this. Great information!

 

[jcanoe]

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.

 

[iustin]

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]

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]

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.

 

[frankvb]

The 20" tires have 101 XL weight rating, while the 19" ones have 104 XL. That might explain the different tow ratings (or at least the max weight on the towing hook).

 

[dnswy]

The 20" tires have 101 XL weight rating, while the 19" ones have 104 XL. That might explain the different tow ratings (or at least the max weight on the towing hook).

Does it mean if I can find another set of 20" tires with 104 XL rating, I could tow 3500 lb with 4 or more people?

 

[frankvb]

Does it mean if I can find another set of 20" tires with 104 XL rating, I could tow 3500 lb with 4 or more people?

I don't see any reason why not, but I'm not an expert in this area so could easily have overlooked something.

 

[jcanoe]

It is not just the tires, the maximum load rating of the 20" Induction wheels have to be considered.

 

[Fourdoor]

When I was looking for optional tires I was surprised to learn that the stock tires on the 19" Gemini's are not listed when you click on "eco focused" tires. I wonder what efficiency difference you get in a MY equipped with the Gemini's and a true eco focused tire?

Keith

 

[jcanoe]

I have not read any reviews of tires for the Model Y with EcoFocus, EcoPlus etc. compared to conventional tires. I have experience with Michelin Energy Saver A/S Eco tires on two different vehicles (one was a plug-in hybrid Gen2 Chevrolet Volt.) While the Michelin Energy Saver tires were ~8% more efficient than non Eco tires the difference may not be worth it. The Michelin EnergySaver tire would hydroplane in the rain at speeds above 50 MPH, certainly by 60 MPH. The rubber compound used in Eco tires needs to be hard, so in cold weather grip is limited. The Energy Saver A/S was the worst tire I have ever driven in snow and one of the vehicles had AWD. Finally, Eco technology includes manufacturing the tire with a stiffer, thinner side wall. The purpose of the thinner sidewall is to recover as much energy as possible when the tire flexes as it rolls. The thin sidewall used in the tire's construction is its Achilles heel. Even with Kevlar fabric reinforcement the sidewalls of Eco tires such as the Michelin EnergySaver A/S tire are famously fragile. The least contact with a curb could damage the sidewall necessitating replacing the tire.

 

[Fourdoor]

I have not read any reviews of tires for the Model Y with EcoFocus, EcoPlus etc. compared to conventional tires. I have experience with Michelin Energy Saver A/S tires on two different vehicles (one was a plug-in hybrid Gen2 Chevrolet Volt.) While the Michelin Energy Saver tires were ~8% more efficient than non Eco tires the difference may not be worth it. The Michelin EnergySaver tire would hydroplane in the rain at speeds above 50 MPH, certainly by 60 MPH. The rubber compound used in Eco tires needs to be firm, so in cold weather grip is limited. The Energy Saver A/S was the worst tire I have ever driven in snow and one of the vehicles had AWD. Finally, Eco technology includes manufacturing the tire with a stiffer, thinner side wall. The purpose of the thinner sidewall is to recover as much energy as possible when the tire rolls. The thin sidewall used in the tire's construction is its Achilles heel. Even with Kevlar fabric reinforcement the sidewalls of Eco tires such as the Michelin EnergySaver A/S tire are famously fragile. The least contact with a curb could damage the sidewall necessitating replacing the tire.

Yup. These are the tires I have on my Bolt. Fantastic for range, horrible for performance. But they do make performance tires that are eco focused and I thought that with the MY LR they would have went with something like that to boost the range rating since it is not the "high performance" version of the MY. I am picking up a set of Gemini's with the stock tires early next month, and selling my Ubertirbine's so I will have an efficiency bench mark between those two... but no data to add for the 20" wheels.

Keith

 

[jcanoe]

The OE tires on the Chevy Bolt are Michelin Energy Saver A/S tires with Michelin SelfSeal technology. The SelfSeal technology is supposed to seal any punctures in the tread area up to 1/4". The SelfSeal technology add ~2 lbs to the weight of the tire, slightly lowering the tire's efficiency.

 

[jcanoe]

Model Y range loss with different wheel sizes (the range loss for the 20", 21" wheels versus the 19" wheels increases with speed):

Range loss with the different wheel options

 

[Crypto2k3]

Just came across this post that compares range loss between 19 and 20 inch wheels and thought I would share:

Tesla Model Y Real-World Range Loss With 20-Inch Wheels

Opting for a Tesla Modle Y with 20-inch factory Induction Wheels over the 19-inch Gemini factory wheels? Here's how much range you should expect to lose.

insideevs.com

TL;DR -

Tesla Canuck uses the TezLab app to capture the data from his range tests. He has the app running in both cars. Based on the test, the Model Y with 19-inch wheels proved to be about 7-percent more efficient than the Model Y with the 20s. In other words, the Model Y with the 20-inch wheels used 3.6 km (2.2 miles) more range than the Model Y with the smaller wheels.

Based on the information from the test, the Model Y with the smaller wheels should get about 36 km (22.4 miles) more range overall than the Model Y with the larger wheels.