Gravity EPA docs are here.

[hmp10]

Also the Performance wheels are staggered so at least the rear is wider.

Do you mean on the Gravity? If so, all three wheel sets have both staggered widths and diameters.

 

[Elfin]

Do you mean on the Gravity? If so, all three wheel sets have both staggered widths and diameters.

No, I'm quoting the video posted which is about a Model 3 Performance.
A small correction, the OEM 20" PZ4 tires are all season but they are wider and much stickier than the OEM 18" tires (70-0 braking 163ft vs. 178ft skidpad .92g vs. .84g)

I think the same will hold true for the Gravity, if you put sticky tires on the 20/21 rims it will get similar efficiency and performance to the 22/23 tires.

 

[Knucklehead]

Super weird how he was more efficient on smaller wheels in the controlled environment test you wanted to see. It’s almost as if it’s magic.

I don't need to watch the OOS video to see that the smaller wheels appear more aerodynamic than the larger wheels. Do they have the same tires mounted? The only way to prove your point is to compare two wheels that have rims that are identical (except one is larger) and tires that are identical. It is almost impossible to do that comparison.

Tires that are the same brand and model but have a smaller sidewall will have different rolling resistance. It is even possible the tire compound is different betweent he two sizes due to load requirements, which also impacts rolling resistance. And then there are the rims: I have yet to see a OEM (Tesla or otherwise) make identical rims in two different sizes. You can find that in after-market rims, so you could do a test by comparing two identical aftermarket rims in two different sizes. That is not what OOS did, right?

If you did that test, everything exactly the same except wheel size, what would be the results? I suspect the smaller wheel would win because it would be more aerodynamic. A larger sidewall means lower rotational resistance. But if the rim is super aerodynamic, the difference could be so small that it is unmeasurable. OOS did not do this test. Did they?

Why do you fail to understand that wheel size is not the variable that matters?

There are three variables that matter: aerodynamics, rolling resistance and weight. That is it. Of course, those variables are loosely correlated with wheel size. A smaller wheel is likely to be lighter and more aerodynamic. But a smaller wheel with the wrong tire can be worse because of rolling resistance. And you can have a very aerodynamic rim that is larger than a smaller one with poor aerodynamics. And a larger wheel that is lighter than a smaller wheel. Rivian has clearly demonstrated that wheel size is not a relevant factor related to efficiency.

Wheel size isn't what matters at all. Focus on what does, and then you can understand why the EPA results for the 21/22 vs. the 22/23 wheels are so similar. It makes sense to me.

 

[Elfin]

Focus on what does, and then you can understand why the EPA results for the 21/22 vs. the 22/23 wheels are so similar.

I agree with most of what you said but the 21/22 and 22/23 data is fake. There is a 0% chance that all three coefficients are exactly the same to 4 digits (F0 F1 F2 in post #19).

 

[TahoeMichael]

I agree with most of what you said but the 21/22 and 22/23 data is fake. There is a 0% chance that all three coefficients are exactly the same to 4 digits (F0 F1 F2 in post #19).

I have some (long out of date) experience with homologating motorcycles in the USA. There's a lot of interesting data produced during the process, but the rules are both a bit arcane and also leave lots of room for interpretation for what's required in the testing. When I was involved, the process required an engineer who also had a law degree. The data tends to be interesting, but also doesn't do a good job of telling vehicle owners what they'd really like to know about a vehicle. I don't know how the regulations have changed in the last 30 years, but it certainly used to be true that one didn't have to separately test every variation.