self made aero wheels

[The Duke]

Looking forward to some real numbers.
I see the TESLA/EPA tests posted all over. Too bad so many actually buy this crap as a solid aerodynamics test for us. As said in the Electrik article "Some of the tests were performed on a dyno machine and at 50 mph (80 km/h). In real-world conditions and at higher highway speeds, other factors like wind resistance set in and reduce the importance of the rolling resistance, which is what is accounted for in those tests." The EPA tests on a dyno. Wheel size vs rolling resistance should be relevant, but wheel aerodynamics is not tested like real life.
Not sure how many of you drive on dynos or at 50 mph, but I don't. Getting off the dyno changes the aerodynamics as you now have air moving around the car and can totally negate wheel aerodynamics. I want my range to be the best at 80 MPH.

I asked a streamliner bike owner running Speed Week one time about wheels and he said "doesn't matter, the air never hits them." He ran spoked rims at 180 MPH.

If you care, here is more info.
Passenger Car Fuel Economy, EPA and Road

 

[Evogreen]

Just got some numbers for covering 19" slipstream wheels. I saw just over 4% improvement at 110km/h.

 

[CalBlue 85D]

If Tesla could get an extra 13.5 miles out of a battery, don't you think they would offer the option themselves? What's the downside if you can make a measurable difference in range just by offering a different wheel cover? If so, why don't they.....

 

[MP3Mike]

If Tesla could get an extra 13.5 miles out of a battery, don't you think they would offer the option themselves? What's the downside if you can make a measurable difference in range just by offering a different wheel cover? If so, why don't they.....

They do, just only on the Model 3 currently. They used to offer the Aero wheels, but they were "ugly" and almost nobody bought them.

 

[The Duke]

Could you post your actual runs with full information? Just saying 4% does not say much. I was hoping for multiple tests of wheel cover on loop, wheel cover off loop for multiple iterations. 4% is a very small amount to measure on public roads.

I tried some tests when I changed rotors and wheels, but gave up as they were all within 5%. Ride quality is subjectively much better. In the end I just have to justify the change with theoretical arguments.

 

[scottm]

I think there's also a similar case to be made here, without too many scientific measures... knowing you're probably saving maybe 5% efficiency is cool, seems reasonable, and just be happy with that!

Instincts alone suggest it can't be worse. Sure, driving the car differently, wind direction shifts, ambient temperature, state of charge, etc.. all factor in but who cares? 4% on a bad trip 8% on an excellent one... it's all good!

 

[Evogreen]

Could you post your actual runs with full information? Just saying 4% does not say much. I was hoping for multiple tests of wheel cover on loop, wheel cover off loop for multiple iterations. 4% is a very small amount to measure on public roads.

I tried some tests when I changed rotors and wheels, but gave up as they were all within 5%. Ride quality is subjectively much better. In the end I just have to justify the change with theoretical arguments.

It's not new information that covering your wheel will give you better efficiency, however it will vary depending on the size of the wheel. How i did the testing was to do a route with the covers on and then do the same route on the same day with the covers off and then compare the wh/km to figure out the % improvement. I drove from my house to a location 90km away, noted the energy use then drove back home and again noted the energy use again. I was careful to have the car already warmed by a previous trip and I used the same accessories (hvac, radio, etc) on each trip.

 

[jeff mccabe]

It's not new information that covering your wheel will give you better efficiency, however it will vary depending on the size of the wheel. How i did the testing was to do a route with the covers on and then do the same route on the same day with the covers off and then compare the wh/km to figure out the % improvement. I drove from my house to a location 90km away, noted the energy use then drove back home and again noted the energy use again. I was careful to have the car already warmed by a previous trip and I used the same accessories (hvac, radio, etc) on each trip.

Your route has to be round trip, in order to cancel out wind and elevation changes.
When I test, I do my loop with device on the car, then another loop without, then to confirm any improvement , I do it again with the device reinstalled . Oh course same day doing this.

 

[Evogreen]

Your route has to be round trip, in order to cancel out wind and elevation changes.
When I test, I do my loop with device on the car, then another loop without, then to confirm any improvement , I do it again with the device reinstalled . Oh course same day doing this.

It was a round trip. I went to a location noted the energy use then drove back and noted again. Once with them on and once with them off, giving me 4 data points. not just 2.

 

[jeff mccabe]

It was a round trip. I went to a location noted the energy use then drove back and noted again. Once with them on and once with them off, giving me 4 data points. not just 2.

Good work

 

[Bluechip]

It needs to be a blind test too. If you know which wheels you are using it may influence your driving style even if you are careful. Seriously, 5% would be well within a reasonable margin of error.

 

[Evogreen]

My tests fell within reason as to what result i expected. I set the cruise control at a certain speed and never adjust anything unless i have to. I have done 4 separate tests now and I would bet my results are correct plus minus a half a percent.

 

[Evogreen]

Tesla would not put aero covers on the model 3 and briefly sell aero rims for no reason. The reason they sold them was because they provide higher efficiency.

 

[David99]

Is that just rubber dots between the disk and the rim? My disks have the same mounting method. Custom lug nuts allow the disks to be mounted on them and the disk only touches the rim at the very edge. The problem I found after driving with them for many thousands of miles is that the forces on the rims are quite significant. The rim flexes and the disks flex differently. Both in normal driving and more so when driving fast and thew wind forces push and pull on the disks. You get a lot of movement between the rims and disks. A lot of dirt gets caught there as well. The disks also create sounds which I wasn't a big fan of. After all my tests I'm not convinced of the disk concept any more. I think a truly closed (or almost closed) rim would be the best solution.

 

[Evogreen]

Yes they are rubber bumpers that keep the clear disk from touching the rim. My disks do not mount in the exact same manner as yours. I do not use custom lug nuts. They are the stock lug nuts. There is no permanent modification required to mount my disks. There is no noise from my disks. I have done a few thousand kilometres with these installed and there are no marks from scratching. They do hold the dirt and brake dust in, but that can be cleaned off.

 

[Evogreen]

Is that just rubber dots between the disk and the rim? My disks have the same mounting method. Custom lug nuts allow the disks to be mounted on them and the disk only touches the rim at the very edge. The problem I found after driving with them for many thousands of miles is that the forces on the rims are quite significant. The rim flexes and the disks flex differently. Both in normal driving and more so when driving fast and thew wind forces push and pull on the disks. You get a lot of movement between the rims and disks. A lot of dirt gets caught there as well. The disks also create sounds which I wasn't a big fan of. After all my tests I'm not convinced of the disk concept any more. I think a truly closed (or almost closed) rim would be the best solution.

See previous post.

Also I used some of your older posts to give me ideas on how to create my version of the cover, so I thank you for putting up your information on your covers.

 

[Stiction]

What a great idea to use clear plastic! I like it.
Question: How about supercharging? Wouldn't you need to remove the left front so the cooling fan can get the air out?

 

[David99]

What a great idea to use clear plastic! I like it.
Question: How about supercharging? Wouldn't you need to remove the left front so the cooling fan can get the air out?

No problem with supercharging. The air is blown onto the tire and it flows to the sides from there. It does not go through the rim. Disks don't affect the cooling.

 

[CalBlue 85D]

They do, just only on the Model 3 currently. They used to offer the Aero wheels, but they were "ugly" and almost nobody bought them.

My bad, I was not aware of the old aero wheels. I've occasionally seen those on older cars, but I had no idea that Tesla sold them as aero wheels. They certainly didn't look as good as the disc style wheels or covers do.

 

[MarkDFW]

The dots are clear plastic bumpers so the rim does not get scratched, the material is polycarbonate. The design is flat and i wanted it to be clear so as to not hide the nice rims and painted brake calipers. In my opinion the opaque disks are not good looking. The clear cover comes off with 5 small bolts, so it's easy to take them on and off for cleaning and checking air pressure. No balance issues and I have gone up 150 km/h with them on.View attachment 258447 View attachment 258447 View attachment 258448 View attachment 258449 View attachment 258447 View attachment 258448 View attachment 258449 View attachment 258450 View attachment 258451 View attachment 258452

@Evogreen ive been toying around with trying a “pizza pan” approach with my Model x 60 for road trips to gain some range back. I think your design is beautiful. However looking for something safe yet more cost effective.

It came to mind that the truly special part of your install is the adapter on the lugnuts. So you are not “drilling into the wheel” like the OP example. The acrylic is nice ... but to save some money have you considered using your “adapter” to attach simple/easy/cheap pizza pans to it? Any reason why you could not do this and avoid making the acrylic overlay (you would lose the looks of course)?

Perhaps it is the adapter/connector that is the expensive part for you to make? How did you make it if you don’t mind us asking?

Thanks! Cool idea for sure!!