Carbon Fiber Underbody spotted?

cvalue13

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I posted this buried in a long thread elsewhere, but with no nibbles/discussion there I on second thought decided I’d tease it out here - as it seems a potentially interesting (confusing?) separate topic:

From investor day, an IG account posted among other things this underbody shot (taken from the front of the vehicle looking back):

Tesla Cybertruck Carbon Fiber Underbody spotted? 0602F49E-CFC3-4B84-81CA-C57736F82382


Towards the front of the truck visible here, there’s a large, plastic, aero extension of the bumper terminating at about the suspension interplay with the underbody.

But just beyond that a new piece of a material picks up, and appears to extend the bulk of the underbody pan (presumably to wherever the back bumper terminates. It is, in effect, the CT’s underbody pan.

I’ve zoomed in and enhanced the photo:

Tesla Cybertruck Carbon Fiber Underbody spotted? 7ACAB074-9DEC-483E-89D7-6729B5AD0BBB


If I weren’t so surprised to find myself thinking that looks like carbon fiber, I’d just assume it’s carbon fiber.

And if it’s not carbon fiber, I’m not sure what else could have this appearance and consistency in geometric pattern, annd even the smoothness of relief and in the turns at the edges. It would be a helluva thing to scribe any metal with such a geometric pattern, especially for a part unseen.

Any thoughts on why this isn’t/couldn’t be a carbon fiber underbody pan?

And if it’s not carbon fiber, what could it be instead?

Basically, for me the oddity comes down to:

• I’d assume for roughness of vehicle the underpan would be a hardened metal of some sort, but I can’t square that with the appearance of this underpan

• I’d otherwise assume by appearance this is carbon fiber, but that would seem a helluva odd choice of a material for a truck purported for off-road use (and otherwise with a 3mm stainless steel body)

*furrows brow scratches head*
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Crissa

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It could also be an artifact of the glossy material reflecting the pulse width modified brightness of the accent lighting, too.

The under-panel does need to be something very tough.

-Crissa
 

TyPope

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I would chalk this up to either a lighting trick or a cover to hide a 2170 battery pack as they haven't started stamping Cybertruck battery packs yet and supposedly, the battery pack will be the bottom of the Cybertruck. What we SHOULD be seeing is the battery pack bottom. Tesla won't be using carbon fiber for production as it has to be baked, is more labor/energy intense to manufacture and they'll already have a steady supply of 3mm Stainless steel in the building.

I fully suspect the final product will be stainless steel. I wouldn't be surprised if the pack has a more substantial steel than the 3mm steel but I wouldn't bet on it. It'll be tough, whatever it is.
 

CyberBC

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The reflections on the undersides of the latest pics look like stainless to me.
 


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cvalue13

cvalue13

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It could also be an artifact of the glossy material reflecting the pulse width modified brightness of the accent lighting, too.

The reflections on the undersides of the latest pics look like stainless to me.
Not stating any authority and instead just co-noodling:

I considered these possibilities and in studying the photo come down to the contrary (but lightly held) view:

First, if I color correct the photo nearly delete the colorization effects of the red lighting, the color qualities of the pan in question becomes more familiarly colored like CF:

Tesla Cybertruck Carbon Fiber Underbody spotted? 762CF130-FE20-43B3-808A-52EF0D381BBE


Second, as far as the striations being some effect of the lighting, given the multiple lights and locations, I’d expect such effect to become duplicative or distorted as it reaches back towards the light sets on the far/passenger side of the vehicle - but (here again photo adjusting for emphasis) the striarion appear to run consistently back the length of the piece:
Tesla Cybertruck Carbon Fiber Underbody spotted? 5E76EF15-3619-43DE-BA09-AE45A48C9B2A


All that said, in studying the photo a third possibility popped out: there are not two pieces here (the plastic front bumper into a carbon fiber full body underpan), but instead three:

• plastic from the bumper underbody (~above the yellow line)

• carbon fiber plate, roughly over the front suspension/motor equipment (~between the yellow and blue lines)

• another material (SS?) for the area between suspension/motor equipment/wheel wells (beyond the blue line) - if you look just “past” the the blue line you can see a seam that appears to run the width of the body and toward the back of the vehicle. And just ‘above’ the blue line, on the purported CF piece, there are two large divots for what in this view would be the attachment points of this middle CF piece, just near the back edge of its extension

Tesla Cybertruck Carbon Fiber Underbody spotted? 12B5BC00-00FF-4F8B-984A-541486C4139A


So to my eye and on this read of there being three distinct pan pieces here, again only as a matter of co-noodling, I take this to be a middle CF pan that rinds the width of the vehicle, roughly correlating with the area of the front drivetrain. This view would mean that beyond this CF piece is essentially the middle pan of the body, in an unknown material, correlating with the area of the battery pack.

PS: see what appears to be a punch-out of the panel in question, seemingly on a feature that would cause the punch out to direct airflow up and around the drivetrain area of the truck.

On that view, this carbon fiber piece functions in part to not retain heat (given CF properties), in contrast to what may occur if encapsulating the drivetrain in a denser SS plate

Tesla Cybertruck Carbon Fiber Underbody spotted? 698BEB1F-E2DA-4F29-A1D6-AD2F333DA4EF
 
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cvalue13

cvalue13

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A different angle of the investor day inside truck (distinct from the Franz truck on investor day):

Tesla Cybertruck Carbon Fiber Underbody spotted? 16B1F096-AF01-475F-8197-C97CEF1C7563


It does appear to confirm three distinct pieces, the plastic bumper, meeting a second piece over the front drivetrain / suspension area, then a third piece behind that consistent with the portion of the truck between the front/back wheelwells

Tesla Cybertruck Carbon Fiber Underbody spotted? 27E630EB-04CE-4555-81F6-4E502CE1AD6B


Tesla Cybertruck Carbon Fiber Underbody spotted? 76D2D627-28C4-4182-85D4-93FCA5DCD53E


in the photo above, note the distinct transition of tones and materials/sheen where the bumper meets the “second piece” (yellow arrow), where the second piece meets the third (green arrow), and then that third piece appearing to be the rather uniform, metallic, battery pack pan with framing for lowering/raising the pack

personally, I wouldn’t bet my life on it, but I’m inclined to say that “second piece” is carbon fiber, molded for airflow around, a dissipating heat from, the motor/drivetrain components. I’d also bet there’s a mirrored piece in the back of the truck, past the battery pack.

note also the second piece’s air scoops earlier shown

Tesla Cybertruck Carbon Fiber Underbody spotted? BEA506F7-E47C-46B3-8D46-911A8C3EC116
 

Crissa

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I do not think you'd scoop air in tiny little bits. They're probably bolt points. The structural pack takes alot of them.

-Crissa
 


WHIZZARD OF OZ

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I posted this buried in a long thread elsewhere, but with no nibbles/discussion there I on second thought decided I’d tease it out here - as it seems a potentially interesting (confusing?) separate topic:

From investor day, an IG account posted among other things this underbody shot (taken from the front of the vehicle looking back):

0602F49E-CFC3-4B84-81CA-C57736F82382.jpeg


Towards the front of the truck visible here, there’s a large, plastic, aero extension of the bumper terminating at about the suspension interplay with the underbody.

But just beyond that a new piece of a material picks up, and appears to extend the bulk of the underbody pan (presumably to wherever the back bumper terminates. It is, in effect, the CT’s underbody pan.

I’ve zoomed in and enhanced the photo:

7ACAB074-9DEC-483E-89D7-6729B5AD0BBB.jpeg


If I weren’t so surprised to find myself thinking that looks like carbon fiber, I’d just assume it’s carbon fiber.

And if it’s not carbon fiber, I’m not sure what else could have this appearance and consistency in geometric pattern, annd even the smoothness of relief and in the turns at the edges. It would be a helluva thing to scribe any metal with such a geometric pattern, especially for a part unseen.

Any thoughts on why this isn’t/couldn’t be a carbon fiber underbody pan?

And if it’s not carbon fiber, what could it be instead?

Basically, for me the oddity comes down to:

• I’d assume for roughness of vehicle the underpan would be a hardened metal of some sort, but I can’t square that with the appearance of this underpan

• I’d otherwise assume by appearance this is carbon fiber, but that would seem a helluva odd choice of a material for a truck purported for off-road use (and otherwise with a 3mm stainless steel body)

*furrows brow scratches head*
You're onto something!
Reminds me of the BMW i3 bodywork.
Has to be light and BAD ASS
( Unlike i3 )
 
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cvalue13

cvalue13

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I do not think you'd scoop air in tiny little bits. They're probably bolt points. The structural pack takes alot of them.

-Crissa
Maybe you’d not scoop out air in tiny bits, maybe you would.

but best I can tell, these are not bolt points (see yellow in question, vs blue bolt point comparison)
Tesla Cybertruck Carbon Fiber Underbody spotted? 39664B7F-1912-4891-84A8-A3473C752E32


Whatever they are, they are cut-outs

And they do appear to be ‘facing’ the right direction, and along an aero channel, that would suggest they were cut out to direct air. (While causing minimal disruption to the flow under the body)

wouldn’t take much air flow there to allow air to ‘clear’ heat between motors and this panel

Separately noting in those cut outs how thin the material appears to be, whether CF or not

Tesla Cybertruck Carbon Fiber Underbody spotted? BCA48C84-FFAB-4A3A-9A61-4DE28C9E7DA6
 
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cvalue13

cvalue13

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It's also a prototype, so they may have chosen a material that was easier to cast in sheets without heavy machinery.

-Crissa
I don’t know anything about how involved it is to design and form carbon fiber in one-off pieces.

But if a goal of this piece is to dissipate heat from the motor etc, then carbon fiber would prob be a go-to material for production

In that case, it would be a decision point between prioritizing heat dissipation, vs prioritizing a off-road protection from obstacles.

On a Rivian, there’s an optional $1,700 shield for off-road performance. It’s standard underbody is set up much like the conjecture for the CT above, but with a separate plastic piece over the motor/suspension area and metal only over the batter. The upgrade turns the plastic piece over motor to I think a composite piece and otherwise thickens the metal in other spots.

I could definitely see Tesla following a different but better approach, where instead of plastic they use CF on the standard version, but have optionality for additional underbody protection.

Importantly, that and similar optionaliry elsewhere would allow Tesla to arrive at EPA milage ratings for a lighter truck, leaving heavier upgrades to options (and so off the EPA radar).

So @Ogre will have to choose: range or brawn

Brings to mind, I’d love to see Tesla do a completely stupid “hypermilage” addition that goes nuts with carbon fiber and other weight reductions changes to arrive at a truck for the people who like to compare their range sizes
 

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Creating one off's carbon pieces for prototypes wouldn't not be difficult at all. CNC negative/positive molds, lay out vacuum.

Production would be a different thing, and probably too costly.
 

Ogre

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The reason Tesla went with Stainless, came from SpaceX. SpaceX was originally going to use a carbon fiber process to make Starship, but after a lot of experimentation settled on stainless. Carbon fiber was lighter, but they needed more heat shielding so ended up being heavier.

But Tesla’s materials engineers very likely still have the benefits of all of that research from SpaceX’s carbon fiber trials. Maybe SpaceX found less expensive ways to make CF? And/ or perhaps ways to make tougher CF?

From what I know about carbon fiber, it makes little sense for Tesla to use on Cybertruck production. The cost and relatively slow production process alone seems prohibitive. I’m more inclined to think this is some kind of injection formed composite (plastic) material just due to price and speed to produce alone. Or maybe it’s a one-off-piece for low volume beta production.
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