Elon: with a lot of work we can get cybertruck cd down to 0.30

[CoyoteJim]

I haven’t seen anything about what the lowest would be or at what speed, but that would have to be factored into the modeling.

Found a reference to 4” travel between low and high position (12”-16”) attributed to Tesla here:

A very serious cfd effort on Cybertruck : teslamotors

Included in a discussion about this study:

Cybertruck Simulation: Deal or Dud? | GoEngineer

 

[JBee]

Thanks for the links. Yeah it should have 4" (100mm) or adjustment. This probably will help, but is not as much as I expected. This also falls in line with the dimensions of my CAD model as that is also the extent of travel that the wheel arches will allow. With the suspension down it still has 11" (288mm) of ground clearance which is a fair bit still, especially for drag. But I'm uncertain as to if its intentional that it doesn't go further down because it doesn't help, or theres something else at work which makes it better with more clearance. The clearance when down is still better than most standard 4x4, and won't have any issues despite the long wheel base. When down its only about 1750mm of the ground to the top of the roof, which is quite low, and lower than a MX in fact.

 

[DarthPierce]

I thought he said up or down 4" which I would interpret as 16" (High, offroad) 12" (Standard) 8" (Very low, highway, loading)

 

[CoyoteJim]

I thought he said up or down 4" which I would interpret as 16" (High, offroad) 12" (Standard) 8" (Very low, highway, loading)

This link is to two Motortrend articles - the first one references 14 inches of travel and 6 inches of air-ride adjustability, although they refer to the lowest position as “kneel” which may refer to the “load mode” rather than a driving mode. The second article talks about which motors are used in the drivetrain and horsepower/torque figures - 690 hp and 824 lb-ft for the DM, 800 hp and 1000 lb-ft for the TM.

Can the Tesla Cybertruck Go Off-Roading? Limits and Liabilities for Tesla's Electric Pickup - Motor Trend

 

[MarcusMaximus]

I thought he said up or down 4" which I would interpret as 16" (High, offroad) 12" (Standard) 8" (Very low, highway, loading)

This was my memory, as well.

 

[JBee]

Huh I somehow missed that Motortrend article, even though they were the first ones I read when the CT came out.

They talk about 14" of travel which is considerable and will keep the wheels nicely on the ground in most terrain. With 16" of clearance that means it should be physically able to get down to just 2". It might only allow users to do 6" of adjustment but that would only be a software limitation. 4" up and 4" down would be quite a feat to keep the geometry working for driving, but their slim differentials actually would allow that sort of long arm suspension. No sidesteps required to get in either, and none to rip off too.

That means we might get a low rider after all for highway use. We might even get a retractable skirt up front redirect air around the vehicle instead of under. That might be how they get the Cd down and the range up. After all in the grand scheme of things for manufacturing costs, I'd think it would be much cheaper to get the body more aerodynamic than add battery capacity.

 

[ohmman]

Moderator note: 110 off topic posts (!!!) moved to Should EVs have efficiency standards?.

Thank you to @JBee for continually trying to keep it on topic. And no thank you to the member who kept trying to get it back off.

 

[CoyoteJim]

We might even get a retractable skirt up front redirect air around the vehicle instead of under.

Cybertruck Giulia Quadrifoglio

The Giulia Quadrifoglio has a drag coefficient of Cd=0.32. So the CT "with extreme effort" could end up with a better cd than the Giulia. That's funny. Part of that is because they want more traction so they're forcing it down, I suppose.

 

[JBee]

Cybertruck Giulia Quadrifoglio

The Giulia Quadrifoglio has a drag coefficient of Cd=0.32. So the CT "with extreme effort" could end up with a better cd than the Giulia. That's funny. Part of that is because they want more traction so they're forcing it down, I suppose.

That is pretty cool. A lot can be done with a few active slats, aero is typically fairly dynamic and quite dependent on velocity so being able to move flows on demand helps a fair bit. I suppose you could even do silly things with the vault cover to create some extra braking force (at the risk of loosing the contents).

The thing I'm still wondering is if the high tailgate was intentional to help trailer aero or "just" the way the geometry ended up. Because another way to improve the aero would be to have a pullout telescopic tailgate that also extends the bed to 8FT. It could also only come out at speed where the extra length is not an inconvenience for parking etc. Something like the back of this:

A lot of this is dependent on it's actual effectiveness, but every bit of improved aero is battery capacity it doesn't have to carry, or be paid for in production. It does increase it's sensitivity to non-aero trailers though. No brute force approach with EV's I suppose, unlike their ICE counterparts.

Another trick would be to use vortex generators (vanes) to control airflow, similar to how they're using the two angles on the front to get airflow around the sides, and also around the A-pillars to create the under pressure behind the rood apex. At some point though you need to abandon solid surface aero, and go full vortex toroidal like smoke rings, and get that air behind you with minimal fuss:

BTW Thanks @ohmman for the thread maintenance.