Cybertruck Aerodynamics / Drag Coefficient Cd analysis by computational fluid dynamics expert

[Woodrick]

It does to me. I probably wouldn't remove the mirrors, but I would look to put low rolling resistance all seasons on.

Everyone has their priorities.

How many 300+ mile trips have you made in the Mach-E? How long have you had it?

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[Knucklehead]

How many 300+ mile trips have you made in the Mach-E? How long have you had it?

My office is 143 miles from my house. I go there 2-3 times per month. When my parents were still alive I drove to their homes fairly regularly - 240 miles one way. My MME gets about 220 miles of range at the speed I drive on the highway when the weather is good.

When the weather isn't good, I get maybe 180. And that is 100% to 0%, which nobody does. I have public charged many, many times and it sucks. I cannot wait to get access to the SC network and take up two spaces charging my MME.

I have had my MME for two years. I am a first time BEV owner. I love the car, but hate public charging with a passion because it is so horrible. Especially when stupid car companies offer "free" charging. Free charging is the worst idea ever because free loaders clog the chargers rather than charge at home.

Now you got me started. Thanks.

So anyway, range is king because 20 miles might mean I don't have to fight to find a place to charge, or I don't have to charge as long.

 

[Glenn]

That's why it's so funny to see the UnPlugged Performance CT accessories - don't get me wrong I'll get some of them (Sway Bar Disconnect, maybe brakes and rock sliders, etc)...but doing the lift kit, rims/tires that are wider/fender flares, bumpers, etc and an already sporty range is going to plummet....

Speaking of brakes, where they going to use a new setup? I remember hearing something but have not since, there brakes were to be the next level up as far as quality, almost brake by wire ( If I remember correct ) Anyone here anything about Brakes? Again, not sure, might have been for one of the sedans.

 

[Woodrick]

My office is 143 miles from my house. I go there 2-3 times per month. When my parents were still alive I drove to their homes fairly regularly - 240 miles one way. My MME gets about 220 miles of range at the speed I drive on the highway when the weather is good.

When the weather isn't good, I get maybe 180. And that is 100% to 0%, which nobody does. I have public charged many, many times and it sucks. I cannot wait to get access to the SC network and take up two spaces charging my MME.

I have had my MME for two years. I am a first time BEV owner. I love the car, but hate public charging with a passion because it is so horrible. Especially when stupid car companies offer "free" charging. Free charging is the worst idea ever because free loaders clog the chargers rather than charge at home.

Now you got me started. Thanks.

So anyway, range is king because 20 miles might mean I don't have to fight to find a place to charge, or I don't have to charge as long.

Okay, awesome history.
I believe that for you, you will find a complete difference in the Supercharge network vs the CCS network. It really is night and day.
The smallest Supercharger site has 6-8 pedestals, the largest, well over 50. And while you may have had some of the plug and play experience with the Blue Oval network, it is 100% that way on the Supercharger network. Just grab that plug that is a quarter of the size of the CCS plug, hit the button on top to open the charge port and plug in.
Superchargers density along Interstates is usually well less than every 50 miles, there are a few 100 mile stretches left around, but probably more 20-mile stretches than 100-mile stretches.

Why do I say that? Because it tends to give you a lot of flexibility in when to stop.

And while this may sound counterintuitive, while road tripping, the fastest way to travel is to stay on the optimum side of the battery curve. That suggests that if you arrive at about 5% and then charge to about 50%, the time at the charger will be minimized. And that is easily 20 minutes to an hour less.

So, on the 500-mile trip, stopping 4 times is going to be faster than the 2-3 times that you are probably doing.

Since you have been charging from DC Fast Chargers for some time, I suspect that you've noticed that the battery charges the first 20% really fast and the last 20% may take 3-4+ times longer. In Tesla batteries, if you are plugged into a 250kW V3 pedestal, you'll take on over 1,000mph up to about 15-20% and that will take just a few minutes. It starts slowing from 250kW at 15% to only 150kW at 35%. And at around 70% it starts dropping below 50kWh. As you may have noticed, charging from 0-50% takes less time than 50-80% and 80-100% takes longer than 0-80%

And with all this in mind, an additional 30 miles of range won't make a difference in the time that it takes to get there. And it doesn't impact the distance that you can go. I just travelled 2500 miles on a trip in December. So, range isn't a problem.

Tesla sells the RWD Model Y that comes with a smaller battery and only about 250 miles of range. It's not restricted to where it goes. And except for 1,000+ mile trips, it doesn't have to stop more often.

 

[Beyond]

Such I wonder how much efficiency and added range if there is an after-market wheel-well cover for highways and freeways and removable for off road driving.

Interesting idea but I wonder if wheel well covers would work with the rear wheel steering, especially since Tesla is going to roll out greater angles as they evolve the software.

 

[Beyond]

Speaking of brakes, where they going to use a new setup? I remember hearing something but have not since, there brakes were to be the next level up as far as quality, almost brake by wire ( If I remember correct ) Anyone here anything about Brakes? Again, not sure, might have been for one of the sedans.

Munro has talked about it a bit. There are systems in existence. As far as real world practicality for a lot of us: I go for days without using the brake pedal except to shift into gear from park. I do try to use it now and then to keep the rotors from rusting. So perhaps not much of an issue for many.

 

[Glenn]

Munro has talked about it a bit. There are systems in existence. As far as real world practicality for a lot of us: I go for days without using the brake pedal except to shift into gear from park. I do try to use it now and then to keep the rotors from rusting. So perhaps not much of an issue for many.

I love my regen, and would love it if it went all the way to stop and hold I was in my wife,s car this weekend, ICE no regen, it stinks going to another car when you drive a Tesla every day with regen.

 

[HaulingAss]

@Gigahorse doesn't listen, so I've given up trying to explain things to him.

The numbers that I just saw posted for the mirrors are very similar to those of the wheel covers on the Model 3 (and others). They are also less than that of many other tires used as options by other drivers.
Why do I mention it, because most drivers really don't care about those range differences. Only a daily basis, it means that you vehicle will stop charging a few minutes different. On a trip, 10 miles of range isn't going to make much difference either.

It's going to similar to the difference between the All-Weathers and the All-Terrain tires. You'll probably see some new Tesla drivers ripping off the ATs as soon as possible to get their range increased. But those who have driven Teslas will just live with them. 20 miles range just doesn't make a difference.

I don't really agree with this for one simple reason, all impacts to range are additive. By ignoring each negative impact as insignificant, you end up with a product that has less capability.

TLDR;

Don't get me wrong, I agree that in normal day-to-day use, 300 plus miles of range is not needed. However, that begs the question why Tesla spends the money to give it 300-340 miles of EPA range (depending upon the configuration). Using the same reasoning, Tesla could have said since range doesn't matter, as long as you have enough, we will save 10% on the most expensive part of the vehicle, the battery, by making it 10% smaller. That would give it 270-306 miles of EPA range, more than enough for typical use. Then they could do it again, since their data shows even that is more range than typically needed. Then the Cybertruck would have 243-275 miles of EPA range, which is more than enough for daily range.

You see what's happening here? The fact is, the range is specified to handle situations in which more range would be faster or more convenient. As the range is shortened, the owner has no choice but to use increasingly less optimum amounts of the battery. That is to say, the owner must now discharge to a lower amount of miles remaining, where options become increasingly limited if things don't go as expected, and they must also charge to increasingly higher states of charge where the charging speed slows more the closer 100% SOC is approached.

To my sensibilities, I'm paying for that 123 kWh battery and I want it to provide the most functionality possible. Sure, if my use case values All-Terrain tires more than ultimate range, I'll still run All-Terrain tires but I'm not going to throw range/efficiency away because "I have enough" without a very good reason. Before you know it, I'm running low tire pressure for a smoother ride, I have racks on top "just in case I need them", I took off the wheel covers because I like the look a little better without them, I fly an American flag off the A-pillar because I'm patriotic, I leave the tonneau cover open because I don't like looking at cameras, I run wider tires because they look cooler, I put bigger mirrors (AKA "elephant ears") on because I want to see more of the road behind me, I carry three spares with me so I will still have a spare if two of them go flat on the same road hazard, I run a big top-box on the rack in case I find a garage sale with a good deal, and I never cruise below 80 mph, because it makes me feel more powerful to drive fast.

None of these non-optimizations are necessarily deal killers on their own, but the cumulative impacts would be atrocious. And the more the owner needs to push the available range of the battery, the worse the charging gets.

Never under-estimate the value of optimizing range and efficiency for increasing the user experience in those edge cases where it matters. Sure, some use cases have such little need for big range, the added inefficiency still might not matter, except perhaps to the extent that more battery cycling causes shorter vehicle lifespan. Instead of 25 years, it might only last 22 years. Maybe you will be dead by then and it won't matter.

I keep our Model 3's optimized for range and efficiency and on long, fast road trips it opens up new options. Sometimes I can skip two Superchargers instead of one, while still remaining in the sweet part of the charge curve. Or, if I want to venture off onto a slower but more scenic route, away from existing Superchargers, I have more options available to me. I love my Aero covers because I love fast driving on wide open backroads.

One of the reasons I love the Tesla design ethos is because I get a special kind of pleasure from driving highly optimized vehicles. That's why I have three Model 3s and zero Model Y's. Very occassionally, when I have a need to transport a lot of bulky items, I wish I had more space so I didn't need to pack my gear in such an optimized manner, but it's worth it to me to be able to drive a vehicle with more optimized aero the rest of the time, I can go further and faster on less.

Tesla worked hard on all their vehicles to optimize range on every little thing, from reducing parasitic brake and bearing drag, to lightening of components, to reducing heating and cooling consumption, to increasing drive motor and regen braking efficiency, to optimizing aero. Because they know these improvements allow them to save on battery costs by specifying a smaller battery that can achieve the same functionality. That's to say the car can cost less, and/or do more with less if they focus on every small incremental gain. Most of these gains have little downside and provide a capable platform from which different use cases can start from. Sure, if you need to travel miles of slippery and muddy steep roads, run All-Terrain tires, if you are Joe Autocross, put some sticker rubber on there. But at least you are strarting with an optimized platform. Every de-optimization is cumulative and should be a conscious choice to achieve YOUR personal goals. But don't discount the range hit entirely or you will end up with a car you may not love anymore.

My Aero covers are often not on my car when using it in normal day-to-day use scenarios because my average speeds are typically pretty low. But you can bet your banana I put them on before I leave on a multi-day trip, even though my Performance Model 3 has free Supercharging for life. One time I forgot to put them on and I regretted it. The car was no longer slicing through the air at 90 mph. I slowed down, not because I needed to, but because it wasn't as fun, it felt like I was hitting the wall and pushing a lot of air, and I didn't want to get into the slow part of the charging curve or stop excessively. Yes, Aero wheel covers make a huge difference on a Model 3 at speeds above 90 mph.

I probably won't drive the Cybertruck at sustained speeds of 90 mph because that's not what Cybertruck is optimized for and it won't give me the same pleasure I get from the fast cruising of my Model 3 Performance on the wide open and little travelled backroads of Washington, Oregon, Montana, Idaho and other Western States. Part of the pleasure is how fast and efficient my Model 3 P can go on so little energy, even though charging is free for me. I can feel the lack of drag relative to other, less aero cars. That slipperiness just feels good to me.

If I did have a need to take the Cybertruck on a roadtrip, for example for exploring more rugged backroads that the Model 3 is not optimized for, then I would take more pleasure at cruising along at a more relaxed and efficient pace, seeing the scenery and discovering new things. Different tools for different use cases. The one thing both use cases have in common is they both benefit from being more efficient. The Cybertruck will be great for connecting little travelled rural country roads from state to state at speeds between 45 and 55 mph, enjoying the scenery and smooth quiet ride. Pro-tip: This kind of travel on sometimes coarse chip seal surfaces is what really benefits in a big way from airing the tires up by up to 10%. Aero still matters but it is much less important.

Not everyone needs to take the same pleasure in efficiency to benefit from keeping their ride as efficient and as convenient as their use case allows. Just know that all non-optimal decisions are additive, there are no free lunches. This is how you avoid the "EV hell" that ignorant people find themselves in and share on-line as if it is inherent in all EVs. For day-to-day use cases efficiency might seem like it doesn't matter much. But who doesn't like to explore off the beaten path? Sometimes all you need is a destination charger at the end of each day to charge back up to 90%-100%.

 

[CyberTruckeeTheOne]

@HaulingAss

Love your write up. With my use case for Cybertruck, that's how I'll be driving it in America's by ways and backroads. And Northern Europe too if I find a cheaper way to ship it.

To think, in my past life, I was the former who have not found a car in front of me I don't want to overtake. Once, a surprised Lambo on I-15 on my daughter's Toyota Yaris (best car in weight-to-power ratio in my book).

 

[Woodrick]

I don't really agree with this for one simple reason, all impacts to range are additive. By ignoring each negative impact as insignificant, you end up with a product that has less capability.

TLDR;

Don't get me wrong, I agree that in normal day-to-day use, 300 plus miles of range is not needed. However, that begs the question why Tesla spends the money to give it 300-340 miles of EPA range (depending upon the configuration). Using the same reasoning, Tesla could have said since range doesn't matter, as long as you have enough, we will save 10% on the most expensive part of the vehicle, the battery, by making it 10% smaller. That would give it 270-306 miles of EPA range, more than enough for typical use. Then they could do it again, since their data shows even that is more range than typically needed. Then the Cybertruck would have 243-275 miles of EPA range, which is more than enough for daily range.

The answer to your question is stupidly simple, not because it is really simple, it's because it is stupid (kind of)

The 300 has become one of those "expected" numbers. The press and the industry has settled in on it. If a vehicle has less than 300, many often make a big deal of it. If it is over 300, then it's not news.

That can be seen in the RWD models, range below 300, but not a huge uptick in sales.

Yes, as I said, kind of stupid.

I believe that Elon has mentioned this a few times.

The 300+ range when degraded for age, when in winter, when at 80% daily charges, when not wanting to go below 20% still provide a more than adequate range that people feel comfortable with. And even if you are daily charging to 50%, it's well above the US daily driving average.

300-mile range has just become a magic number.

 

[Woodrick]

I don't really agree with this for one simple reason, all impacts to range are additive.

Never under-estimate the value of optimizing range and efficiency for increasing the user experience in those edge cases where it matters. Sure, some use cases have such little need for big range, the added inefficiency still might not matter, except perhaps to the extent that more battery cycling causes shorter vehicle lifespan. Instead of 25 years, it might only last 22 years. Maybe you will be dead by then and it won't matter.

I keep our Model 3's optimized for range and efficiency and on long, fast road trips it opens up new options. Sometimes I can skip two Superchargers instead of one, while still remaining in the sweet part of the charge curve. Or, if I want to venture off onto a slower but more scenic route, away from existing Superchargers, I have more options available to me. I love my Aero covers because I love fast driving on wide open backroads.

I don't disagree with you at all, cumulative impacts are deadly. That's why Tesla puts so much time into every little piece. If you don't put that time in, you get a Hummer EV, you have to add extra battery to get over your poor design.

The reason that I bring up the fact that every little bit doesn't necessarily matter, is to get some of the people with huge range anxieties something to pause and think about. Charging from 20-80% isn't the best way to travel. Travelling from 20-100% is the worst way to travel. EV road tripping is a different paradigm.

And I pride myself on skipping Superchargers, but still staying on the good side of the battery curve. It adds a little fun to a drive.

My biggest point is that range isn't the biggest factor in an EV. Just like it isn't the biggest factor in ICE vehicles.
On trips, especially Interstates, there aren't gas stations everywhere, commonly they are about 10 miles apart, at the exits. But you don't worry about it. (unless you happen to see that you are low) For EVs, the charging locations aren't quite that close, but in most locations, it's about 50 miles. And we're to the point where, as you mentioned, we skip the majority of locations, stopping only for those most convenient to us.

 

[HaulingAss]

The answer to your question is stupidly simple, not because it is really simple, it's because it is stupid (kind of)

The 300 has become one of those "expected" numbers. The press and the industry has settled in on it. If a vehicle has less than 300, many often make a big deal of it. If it is over 300, then it's not news.

That can be seen in the RWD models, range below 300, but not a huge uptick in sales.

Yes, as I said, kind of stupid.

I believe that Elon has mentioned this a few times.

The 300+ range when degraded for age, when in winter, when at 80% daily charges, when not wanting to go below 20% still provide a more than adequate range that people feel comfortable with. And even if you are daily charging to 50%, it's well above the US daily driving average.

300-mile range has just become a magic number.

I've never been to Georgia so maybe I should ask what you consider "winter weather" in Georgia? Or what constitutes a big mountain pass? How about a big mountain pass in winter weather on a dead-end highway to the mountains, with icy roads and no trucks sanding or de-icing and no houses or cell service for miles?

Last weekend I left on what is normally a 90-mile trip to my rural ski cabin where I have a 48-amp Tesla Wall Connector on a pedestal in the driveway. I started the trip at the 57% SOC it was at when I was ready to depart. 90 miles, piece of cake, right? It was very cold when I left home, about 15 degrees F, but it kept getting colder and I had a stiff NE headwind. The temperature eventually got down to 3 degrees. About half-way there, the WSDOT had erected a sign that said the State Highway was closed about 8 miles ahead. This is a rural area with mountains and rivers, so the highway is the only direct road through. I learned later a tree had fallen over in the arctic blast and had taken down some high-tension lines with it. The detour made me backtrack about 25 miles and eventually took me within a couple miles of Canada, after making an impromptu dinner stop to figure out whether the highway would open up that evening (it would not). During dinner it was 7 degrees F and the car was cold-soaked after dinner, requiring a multi-kilowatt blast from the heater and full seat heat to make the cabin habitable. Realizing I didn't have a lot of margin for error in the freezing weather with a stiff NE wind I backtracked at conservative speeds and took a more northerly route, on even more rural roads that wind through the tall foothills. Many of these roads I had not been on for years and some of the steeper, tighter ones were coated in a layer of ice making them treacherous. There were no streetlights, zero traffic, and the night was as dark as ink. I knew I could make it with range to spare, but perhaps not if one more thing went wrong, like another tree over the road, or even if slid off the shoulder of the road and needed to search out another motorist from a rural mountain home to yank me back on the road. Most people would not want to drive on such a slippery and steep, twisty road.

To make a long story short, nothing else went against me, so yes, I ended up with range to spare, about 12%. But I didn't like the idea of having such a low state of charge on such a cold night in such a remote location. The point here is a person from Georgia cannot say what is adequate range for a person with a different use case and a bit more reserve comes in very handy when things go awry. This was a relatively short trip, and it would have only taken one more thing to go against me for me to be in an unhappy place. There was no cell service for most of the second half of the route. To be clear, I've been in similar rural situations in gas cars and trucks, in frigid weather running below 1/8 tank due to unforseen circumstances and it is no more pleasant.

Sure, on well populated Interstates, travelling by Supercharger, and in more mild weather, I don't feel like I need a very big buffer to deal with contingencies. But not every use case is like that or free from a confluence of unexpected events that conspire against you.

 

[Woodrick]

I've never been to Georgia so maybe I should ask what you consider "winter weather" in Georgia? Or what constitutes a big mountain pass? How about a big mountain pass in winter weather on a dead-end highway to the mountains, with icy roads and no trucks sanding or de-icing and no houses or cell service for miles?

I have been to 49 states and am familiar with many of the US mountain ranges and how desolate they can be. I've even made the drive from Anchorage to Fairbanks in September in 2003, when the roads weren't paved, cellphones didn't cover most of the route and there was 350 miles of only seeing a handful of vehicles. I was in a rental ICE and knew that if I went off the road, I could have been 100 miles further from civilization than you were. Oh, the route went within a few miles of the highest peak in North America.

When I'm saying range isn't everything. That doesn't include the edge cases that you bring up. Because for every edge case, there's one that's worse. So if the truck had 700 mile range, someone will bring up a cabin in Northern Alaska that the truck just won't be able to reach.
I mean, what if your cabin was 130 miles? You wouldn't have been able to make it.

But reality is that situations like your cabin are rare. That's obvious, because the roads that you were using weren't heavily travelled, there wasn't a lot of infrastructure.
Sure there are a number of people complaining about situations where the truck doesn't have enough range, but I lay odds, that's less than 5% of the prospective buyers.

Would I like a 1,000 mile battery that charges in 15 minutes and costs $20k? Sure. But it just doesn't exist yet. So we have to do what we can with what we have.

In Georgia we are hitting about 15 tomorrow and out highest peak is 3500 ft. I regularly go over the Smokies at 5500 feet, but no we don't have Ranier, I have skied at 13,000 ft though.

My point? Let's get real and solve the situations that we can.

And in your case, if you had run into snow and become stuck, the Model S may have kept you from freezing longer than an ICE vehicle may have (without the chance of carbon monoxide poisoning).

 

[HaulingAss]

When I'm saying range isn't everything.

But I didn't say range was "everything". I simply said it's a good idea to not unnecessarily handicap your range by saying minus 5% here, 5% there, doesn't matter. You paid for those batteries, make the most of them. They will last longer if your car isn't wasting it uneccessarily while driving down the highway.

 

[Woodrick]

But I didn't say range was "everything". I simply said it's a good idea to not unnecessarily handicap your range by saying minus 5% here, 5% there, doesn't matter. You paid for those batteries, make the most of them. They will last longer if your car isn't wasting it uneccessarily while driving down the highway.

But as you said, I do want to make the most of it. I'd rather drive 75mph. I don't like the look of the aero caps. I like to leave the roof mounts on.
I will often accept less range in exchange for something else.

And that's what Tesla had to decide with the Cybertruck. They could have given it 500 miles @ 75 mph range. It would raise the base price of the vehicle significantly, and remove some storage or increase the size so that it doesn't fit in many garages.

I'm guessing that you may have been able to lighten your luggage some on your fateful trip, but it was your trade-off that it wouldn't make that big of a difference.

If you want to talk handicap, I believe that you mentioned that you started at 57% SoC. You intentionally handicapped your trip, by a large number. You decided that 90 miles was no big deal.

I mean was it smart to start a trip at less than max at 5 degrees? Many would not have done that in their ICE.

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