Metal roof rather than glass on the Cybertruck

[firsttruck]

How much metal is really required here? Why not just adhere a thin sheet of metal (like the thickness of aluminum foil) to the already existing glass?

The issue is not to have a metal veneer for looks.

The glass roof makes the vehicle more expensive to fabricate and takes more time to make

glass roof will cost owners more over the life of the vehicles
( Yes, not every owner will have a direct repair incident but over all vehicles there will be higher costs. The place most owners will see this is that insurance has to be higher to cover the higher costs)

glass roof vehicle are harder to mount accessories and other equipment on.
Things like antennas, light bars, special police/fire/emergency equipment, racks.
Can you drill a hole in glass roof without cracking the $1,000 glass roof ?
Can you drill hole in armor glass roof?
Is there special process to drill a hole in glass roof?
Will you trust the installer to drill without cracking your glass roof? How do you get the installer to pay for replacement if roof cracks?
Will most installer not even offer installation on glass roof because they do not want to be liable.
There are already installers & mechanics that refuse to work on Teslas.

Glass roofs have more seams that can leak water. If you search Internet you find many incidents of leaky roofs.
( Yes, metal roofs can leak too. The problem is that glass roof have more seams than standard metal roofs).

What about if a medium size rock falls from high cliff, bridge, overpass, building and cracks the armor glass roof.
A cracked glass roof absolutely will need to be replaced.
The same rock incident would dent a 3mm cold-rolled stainless steel. The owner could safely decide not to get the dent fixed.

Radio antennas for transmitters do not work well on glass roofs.

Business owners of Cybertruck should not have to pay more for Cybertruck because of glass roof.
About 25% of vehicles are used by businesses. There are probably a lot of non-business owners that also would like to save $1,000 on Cybertruck and save on insurance.
Truck owners that do not need a transparent roof or just believe that money ($1,000) could be better used on other things should not have to subsidize those that want such an expensive ($1,000) luxury item.

Advertisement

 

[MEDICALJMP]

The issue is not to have a metal veneer for looks.

The glass roof makes the vehicle more expensive to fabricate and takes more time to make

glass roof will cost owners more over the life of the vehicles
( Yes, not every owner will have a direct repair incident but over all vehicles there will be higher costs. The place most owners will see this is that insurance has to be higher to cover the higher costs)

glass roof vehicle are harder to mount accessories and other equipment on.
Things like antennas, light bars, special police/fire/emergency equipment, racks.
Can you drill a hole in glass roof without cracking the $1,000 glass roof ?
Can you drill hole in armor glass roof?
Is there special process to drill a hole in glass roof?
Will you trust the installer to drill without cracking your glass roof? How do you get the installer to pay for replacement if roof cracks?
Will most installer not even offer installation on glass roof because they do not want to be liable.
There are already installers & mechanics that refuse to work on Teslas.

Glass roofs have more seams that can leak water. If you search Internet you find many incidents of leaky roofs.
( Yes, metal roofs can leak too. The problem is that glass roof have more seams than standard metal roofs).

What about if a medium size rock falls from high cliff, bridge, overpass, building and cracks the armor glass roof.
A cracked glass roof absolutely will need to be replaced.
The same rock incident would dent a 3mm cold-rolled stainless steel. The owner could safely decide not to get the dent fixed.

Radio antennas for transmitters do not work well on glass roofs.

Business owners of Cybertruck should not have to pay more for Cybertruck because of glass roof.
About 25% of vehicles are used by businesses. There are probably a lot of non-business owners that also would like to save $1,000 on Cybertruck and save on insurance.
Truck owners that do not need a transparent roof or just believe that money ($1,000) could be better used on other things should not have to subsidize those that want such an expensive ($1,000) luxury item.

The Rivian sounds like a better choice for you. I don’t see Tesla changing to a steel roof due to weight, structural issues.

 

[firsttruck]

I don’t see Tesla changing to a ,teal roof due to weight, structural issues.

What weight issue is there in having 3mm cold-rolled stainless steel roof?

Do you know how much the armor glass roof weighs?

What structural issues?

The Rivian sounds like a better choice for you.

Cybertruck will be a great work truck. Rivian R1T with 4.5' bed is a toy truck used for play.

Rivian does not have:
3mm cold-rolled stainless steel
no paint low maintenance body
cool angular polygon design
6.5' bed with tailgate closed
secure bed vault storage
armor glass windshield & side windows
FSD ( Rivian R1T has nothing even close to Tesla FSD)
payload 3,500 lbs (Rivian only 1,750 lbs)
towing 14,000 lbs
air suspension
Electric outlets 120/240V in truck bed for powering tools
Air compressor for powering tools
Seating for 6 passengers
option for solar panels ** real self-charging EV
longest range - Cybertruck 560mi ($69,000 Rivian R1T 300 mi)
price - Cybertruck with all the standard features plus FSD is much better value

Tesla Cybertruck Vs Rivian R1T: Infographic and Comparison
By: EVANNEX
Jul 18, 2020
https://insideevs.com/features/434634/tesla-cybertruck-rivian-r1t-comparison-infographic/

 

[TechOps]

What weight issue is there in having 3mm cold-rolled stainless steel roof?

Do you know how much the armor glass roof weighs?

What structural issues?




Cybertruck will be a great work truck. Rivian R1T with 4.5' bed is a toy truck used for play.

Rivian does not have:
3mm cold-rolled stainless steel
no paint low maintenance body
cool angular polygon design
6.5' bed with tailgate closed
secure bed vault storage
armor glass windshield & side windows
FSD ( Rivian R1T has nothing even close to Tesla FSD)
payload 3,500 lbs (Rivian only 1,750 lbs)
towing 14,000 lbs
air suspension
Electric outlets 120/240V in truck bed for powering tools
Air compressor for powering tools
Seating for 6 passengers
longest range - Cybertruck 560mi ($69,000 Rivian R1T 300 mi)
price - Cybertruck with all the standard features plus FSD is much better value

Tesla Cybertruck Vs Rivian R1T: Infographic and Comparison
By: EVANNEX
Jul 18, 2020
https://insideevs.com/features/434634/tesla-cybertruck-rivian-r1t-comparison-infographic/

I don't want a metal roof, I want a glass one. If you want a metal roof, buy a different truck. The Cybertruck doesn't come with one, either standard or as an option.

 

[firsttruck]

If it's not a glass roof it would make a lot of sense to have solar panels instead. Structurally it would still be made out of a sheet of SS probably

Yes, Tesla factory OPTION, switching glass roof for durable high performance solar panel in hole where glass roof was, integrated & flush-mounted with exoskeleton so no extra drag.

The space might be large enough to get 850W to 950W and hour.

If Tesla can figure out how to do solar on the tonneau cover that might be another 850W

The total would be level-1 charging rate. On sunny summer day charge 100kwh pack up to 30 miles a day.

This would be another gaming changer. Real self-charging.
More than battery range of new Jeep X4e PHEV ( 25 mi ).
Stomp all over the fake self-charging Toyota PHEV.

 

[firsttruck]

Well I would highly debate that. Pickup trucks are the best selling vehicles in America.

Actually that is not correct. The headlines you see say "light trucks" are the best selling.
most SUVs are classified as light trucks.
SUVs outsell pickups by almost double.

go to texas, they are more prevalent than cars.

I live part time in Texas. Even in Texas today, new vehicle sales are dominated by these "light truck classified" SUVs.

you think all the trucks driving around the highways and cities are farm/contractor/fleets, no. like i said probably 10%

Yes it is a lot more than 10%.
Fleet sales alone are 20-25%. There are tons of non-fleet business buyers so total is probably 30%.

Then on top of that there are probably many regular buyers who do not care about a glass roof and want a cheaper Cybertruck. Ford F-150 MSRP starts at $29,000 but with dealer discounts the real price is lower. There are a lot of people that just can not pay Cybertruck $39,000 + $1,200 destination fee.

Pickup trucks are the most gas hogs on the road. If we want a sustainable future we need Cybertruck to be more affordable.

Full metal roof Cybertruck can be fabricated faster ( more trucks made per day) and just that alone would make Cybertruck cheaper. Tesla is going to have a huge backlog of orders. Faster production gets more BEV trucks on the road.

 

[firsttruck]

No. Because they are already planning on a glass cabin. So adding a different cabin configuration would be the added cost.

I said before I have spent years working in steel metal fabrication companies.

Sorry, but a different cabin significantly increases costs is NOT true for the Cybertruck.

The reason for the increased cost with traditional curved vehicle designs is because each body panel (11 or more) requires expensive stamping presses and dies.
I agree with Sandy Munro when he said in product design & fabrication, curves cost money.

Tesla even stated that one of the primary goals of the Cybertruck design was eliminating the need for stamping presses and dies usually used to make exterior body panels. Sandy Munro said the same thing. This hugely reduces the CAPEX for Cybertruck.

Also because there are no stamping presses & dies for exterior panels, Tesla could make the cheaper full metal roof style Cybertruck for less money and sell for cheaper than $39K & also sell glass roof version for $39K. Tesla could also make more metal roof Cybertrucks per day than glass roof model.

 

[firsttruck]

glass is actually stronger than a metal roof?

As I said before not all glass is stronger than all metals

In product design, the word stronger is not a simple specification.

Stronger in what way?
tensile?
resists compression?
durable
ductile
hardness?

Hardness is a measure of how easily a material can be scratched or indented. Hard materials are often also very brittle - this means they have a low resistance to impact

If you are doing something to the CT that will cause the (incredibly strong) frame to flex to the extent that it could crack glass in the roof, you have a much bigger problem than the roof.

I never said anything concerning flex.

My initial points were
1. reducing Cybertruck fabrication cost
2. reducing lifetime maintenance (damaged, water leaks).
3. reducing insurance costs
4. reducing cost of install equipment & accessories on roof.
5. reducing cost of install equipment & accessories car ceiling (under roof).
6. problems antennas for two-way radios.

The main example I gave was a rock or brick falling on the roof and cracking the glass.
Armor glass is not indestructible just like the Titanic was not unsinkable.

Armour glass has three stages
1. impact level where item just bounces off and no damage to glass.
2. higher impact level where item bounces off but the glass is severely cracked.
3. even higher impact level where item goes through glass and glass is severely cracked.

Stages 2 & 3 will require this very expensive glass to be replaced.

Tesla talked about objects impacting the glass.
Some items crack the crack armor glass but only dents 3mm cold-rolled stainless steel.
There will be similar situation with rocks & bricks where some impacts will be hard enough to crack the armor glass but would only dent the metal roof. The cracked expensive armor glass must while a rock/brick dented metal roof could continue the rest of it's like without repair.

 

[Dids]

Sorry but the way radio works is pretty much defined by physics. The best place for a mobile two-way radio antenna is the center of the roof. It is the highest spot which matters for line of sight communications and it provides the best ground plane. Off center locations affect the direction of the strongest signal and we need omni coverage. I therefore join those who would like the option of a metal roof. I may still buy a Cyber Truck, but every vehicle I've purchased for the last 40+ years has had to accommodate comm gear as a journalist, SAR person and amateur radio operator. This has meant multiple antennas and radios. This hardly matters to most people, but it does matter to me and the F150 with the 40/20/40 seat allows me to yank the middle seat and install a console for comm gear.

This is by no means disparaging the glass roof. It is actually pretty cool, but I would be nervous about cutting holes in it.!

Have you considered using starlink? If glass roof is transparent to starlink it might be beneficial since the antenna is rather large and might do better inside the vehicle.
Actually Elon said at an investor day that lower bandwidth 20-30mb antenna could be smaller

 

[Crissa]

As I said before not all glass is stronger than all metal...

Yes, but the glass they're using is harder than all metal that can be used for this use.

And as we've pointed out:
1) The default is glass. So metal isn't cheaper.
2) Metal requires different structure, so may not actually be cheaper.
3) The metal that you want is actually heavier.
4) Wanting it to shrug off damage means even more structure!
5) Very few trucks use short-wave radios that need large ground planes. There are other ways to do this, too.
6) There are already mounting points on the Cybertruck. A metal roof does not make them 'easier'.

-Crissa

 

[firsttruck]

Yes, but the glass they're using is harder than all metal that can be used for this use.

Harder usually means more difficult to scratch or cut.
Harder is not the same as impact resistance.
Many harder materials are brittle.

Tesla already demoed that Tesla armor glass can crack where the same impact would not have severely damaged 3mm cold-rolled stainless steel.

1) The default is glass. So metal isn't cheaper.

The info I have seen show aluminum oxynitride glass is more expensive.

$10-$15 per sq in.

I am sure Tesla has reduced cost but the raw material cost will not be cheaper than 3mm cold-rolled stainless steel.

Even if metal was option (not default), metal would still be cheaper. (see net item)

2) Metal requires different structure, so may not actually be cheaper.

Metal does not require a different structure. Tesla could just put a metal piece where the glass roof was.

The point is that a full designed metal roof is less complex to make than a glass roof design.
Full design metal roof has much fewer seams that water could leak through.
Full design metal roof is faster in fabrication and assembly so Tesla can make more Cybertrucks in a day.

So Tesla would save millions of dollars when make 100s of thousands of trucks.
Just like there are times when eliminating one 5 cent screw can result in millions saved.

Metal roof is cheaper long term for customer and easy for customer to use and install thousands of accessories on market.

3) The metal that you want is actually heavier.

I see no evidence of metal being heavier.
Armor glass is heavier than equivalent level of protection using metal.
The aluminum oxynitride is less weight that previous armor glass but it is still heaver than steel.

If aluminum oxynitride glass was so strong, so cheap and so light weight they would have made more of the vehicle out of armour glass instead of 3mm cold-rolled stainless steel.

4) Wanting it to shrug off damage means even more structure!

No, wanting to shrug off damage does NOT ALWAYS mean even more structure!

3mm cold-rolled stainless steel needs less structure than armor glass roof.

5) Very few trucks use short-wave radios that need large ground planes. There are other ways to do this, too.

There are millions of trucks that use short-wave radios.

There is existing use short-wave radios infrastructure. If Cybertruck does not work well with that structure many fleets and businesses will not buy. This is a huge market.
Many independent truckers have clients that use short-wave radios and the trucker needs to work within the client's network. You rarely get to tell the client to throw out their infrastructure.

6) There are already mounting points on the Cybertruck. A metal roof does not make them 'easier'.

The mount points that appear to be available are not enough.
There are no mount points where the glass is. There are many example of equipment and accessories that need to be installed where the glass is.

Many installations need holes too of different sizes and placements.

Tesla can not put mount points and holes to cover everyone.

And NO, adding a rack is not good enough. EVs have to avoid extra drag.
Tesla spends lots of time and money eking out 1% saving here and another there...
Drag is not so critical with ICE vehicles. So between the extra costs of rack and the drag created by rack you do not want a rack unless you are already going to carry a bulky or heavy item.

 

[Tim.Luchenko]

Nah, it's Armor Glass just like the rest of the vehicle. What could possibly go wrong?

Did you forget the Unveil event? When Elon Musk broke 2 side windows? They were ARMORED! I personally do not trust armored glass as much as I can trust the steel roof!

 

[T3slaDad]

Did you forget the Unveil event? When Elon Musk broke 2 side windows? They were ARMORED! I personally do not trust armored glass as much as I can trust the steel roof!

To be fair, the media blew up that part of the event stating the windows failed, when in reality they worked as armored glass is designed to do.

You ever shoot a bullet at bullet proof glass before? Spoiler, it shatters to absorb the impact, the bullet doesn't just bounce off. Oh, and it successfully stops the bullet, which is the intended purpose. Normal glass would shatter slightly, but the bullet would cruise on through almost like nothing happened.

People often misconstrue armored glass to be indestructible glass, which it's not. The glass is stronger, yes, BUT it also needs to shatter at some point to absorb the impact and PREVENT PENETRATION.

But hey, the media loves penetration so yeah ?

 

[firsttruck]

To be fair, the media blew up that part of the event stating the windows failed, when in reality they worked as armored glass is designed to do.

You ever shoot a bullet at bullet proof glass before? Spoiler, it shatters to absorb the impact, the bullet doesn't just bounce off. Oh, and it successfully stops the bullet, which is the intended purpose. Normal glass would shatter slightly, but the bullet would cruise on through almost like nothing happened.

People often misconstrue armored glass to be indestructible glass, which it's not. The glass is stronger, yes, BUT it also needs to shatter at some point to absorb the impact and PREVENT PENETRATION.

Agreed.

Stronger in the sense that item did not go through not always that the armor glass will be undamaged.

Hopefully none of us are faced with bullets but there are plenty of incidents where rocks, bricks, other debris falls on a truck roof. If the roof is armor glass it will probably protect us but some times it will leave the owner or insurance company will a very big bill. Even if the insurance pays it will still cost society more. 3mm cold-rolled stainless steel will more often leave no bill.

The design rule is if you "NEED" a transparent panel window in a location sure use armor glass.
But is there is NO "NEED" do not make a hole in wall or roof.

Just like heating a house, a window almost always results in a lot more heat loss that the wall. ( there is an exception if there is a possibility of enough solar gain to offset the extra losses).
If the scene through a proposed window is of a brick wall maybe it is better to leave the wall window free and just put a LCD "window" (ie TV) or artwork where the window would have been.

 

[Crissa]

Harder usually means more difficult to scratch or cut.
Harder is not the same as impact resistance.
Many harder materials are brittle.

Yes.

Tesla already demoed that Tesla armor glass can crack where the same impact would not have severely damaged 3mm cold-rolled stainless steel.

...But no.
The side panel was able to take more impact because it has a heavy metal structure that can flex further. It flexed so far that it broke the edge of the glass!

If you make that a roof panel, you need all those sides to work together to handle the increased load that it will transmit.

Otherwise, your fancy metal roof will just total all your windows and perhaps the frame of the truck - when a glass panel would have just broken and absorbed some of the energy as it flexed and then didn't flex back.

The info I have seen show aluminum oxynitride glass is more expensive.

Yes.

But you're asking for more welding, more folding, more engineering, and a stronger passenger cage to withstand the translated loads. That is more expensive.

Metal does not require a different structure. Tesla could just put a metal piece where the glass roof was.

No.

Again, every material choice has to take into account transferred loads and how it's attached.

The point is that a full designed metal roof is less complex to make than a glass roof design.

Yes.

If that were their initial design. Which it is not.

Full design metal roof is faster in fabrication and assembly so Tesla can make more Cybertrucks in a day.

No evidence for that. A glass roof is a single panel that glues in place. That is very, very simple. Simpler than the folds, welds, and structure required to support a metal roof.

I see no evidence of metal being heavier.

A) 305 stainless steel is 7.99 g/cm^3 while ALON is 3.696 g/cm^3
B) When you use a stronger material, you have to provide structure for transferred loads.

If aluminum oxynitride glass was so strong, so cheap and so light weight they would have made more of the vehicle out of armour glass instead of 3mm cold-rolled stainless steel.

No.

I'm repeating myself, since ALON can't be welded or folded and isn't great at transverse loads. Again, every material choice has to take into account transferred loads into the structure, and how it's attached.

No, wanting to shrug off damage does NOT ALWAYS mean even more structure!

That is literally what that means. All that kinetic energy has to go somewhere!

There are millions of trucks that use short-wave radios.

No.

There are an estimated 15.5 million trucks in the US. Less than one in twenty has a shortwave radio permanently attached.

And NO, adding a rack is not good enough. EVs have to avoid extra drag.

If you wanted to avoid drag, you would not be mounting to the roof. Or you would mount as little as possible, hence using the roof rack mounts. They only need to be as above the glass as they need to flex in service.

Since the roof rack mounts are behind the bow shock of the vehicle, anything low mounted there will have a lower drag cost. Surface attached turbulence you can take advantage of (think the dimples on a golf ball).

It's okay that you want a steel roof. But it won't be cheaper until they're making hundreds of thousands of that option.

The suggestion of a thin steel composite panel to replace the glass is a good one - it could mount exactly as the glass does and shrug off quartz shards all day.

The suggestion of using a roof-rack isn't bad, as that can be any shape, even a grid that provides rock protection and/or mounting points.

You aren't getting a Cybertruck without a glass cabin. You want a Bollinger for that. And that's okay.

-Crissa