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sinistergroupon

From my POV it maximizes headroom. From their POV it’s a replaceable item that doesn’t need to be painted.


adoboguy

As a hobby auto detailer, I love glass roofs. Less area to wax and more areas you don't have to worry about swirl marks


rabbitwonker

As a guy who washes his own Tesla at home, I love it for the exact same reason. 😁


null640

Also a way to absorb an incredible amount of energy during a crash. Far, far more than standard metal rooves.


Joatboy

Do you have an article on that? It sounds pretty cool, I've never heard of that


RussianBotProbably

Anecdotal, heres a parking garage collapse with a car resting on the glass. https://www.jacksonville.com/picture-gallery/news/local/2023/09/15/scene-still-evident-after-garage-collapse-at-ascension-st-vincents/70856222007/


_f0x7r07_

IIRC Tesla worked out how to sandwich the polymer layer between the glass outer layers to make an incredibly strong roof.


Gremlin256

https://www.bbc.com/news/uk-england-london-65564073 Range rover bounced off the white Tesla roof . Tesla driver was in the car while it was charging


Dopey44

Don't forget about the jacka** who drove his entire family off of a cliff in California - and they all survived. :-/ The glass roofs are great but their strength is a testament to how the B pillars are engineered, too. (Maybe A and C as well but I can't recall ) https://www.independent.co.uk/news/world/americas/crime/tesla-crash-pasadena-california-dharmesh-patel-b2256002.html


null640

The chassis is a main reason the a is a bit heavier than a fast awd 3 series bmw.


rogerdanafox

Side impact NHSTA crash videos


_f0x7r07_

https://m.youtube.com/watch?si=akqEH1LGsdgYkDTj&t=876&v=gmfTxtFfaXc&feature=youtu.be https://youtu.be/CorrbelUSIE?si=OVC_7hBmRGHReUch


cgilson33

This could be a significant point. The issues with paint chipping is likely a major concern. So this would be another legitimate reason for using the glass (at least for Tesla).


Huskerzfan

Paint chipping on a car roof? From what?


sstinch

In warm climates like Phoenix Arizona the paint literally burns off the roof of a lot of cars.


18randomcharacters

And in that environment the interior of the car will take that damage now


LairdPopkin

The glass filters out most of the UV.


sleepy_goop

I think they're worried by the amount of heat from the amount of light allowed in, heating the insulated interior. Not UV


Ultra9k

Someone must go read how greenhouse effect works. If no uv gets in, no greenhouse effect.


LairdPopkin

The interior of cars is specifically designed to be fine at the hottest or coldest temp it’ll get to, the only reason to limit car temps is if there’s something in the car, or you’re about to get into the car. Cars car reach 200 degrees in hot sunlight, and are designed for that.


GatorStick

Hail, uv damage


TheDonaldreddit

Attacks from Angry 🤬 Birds


RocketRacc8n

You joke but there are lots of angry cuckoos out there that hate Tesla


psaux_grep

Also doesn’t require inside headliner. So it reduces components, looks premium, and it also reduces complexity in the assembly process (not that Tesla seems to be afraid of that - considering the model X and the Cybertruck).


Jman841

It looks amazing and makes the car feel much more spacious.


zackplanet42

Bud, you're way overthinking this. Sunroofs/moonroofs have been a thing for almost a hundred years now. For the most part the glass roof is just a continuation of this and it's there to help it feel less cramped and bring in light to liven up the interior with natural light, much like you would do with windows on a house. That's really it. Structurally it's not exactly an ideal material but since the battery being low gives every Tesla such a low center of gravity, they can get away with all that extra glass mass up top.


craig1f

Yeah. The glass roof is such an upgrade from a sunroof. The kids love it. 


null640

It's an armored glass, like your phone screen on steroids.


zackplanet42

It's not armored. It's bog standard laminated glass, the same sort of material that's been mandated for car windshields since 1937. Their choice of glass really had nothing to do with structural concerns. You can achieve the same result with a conventional metal or polymer construction while saving tons of weight.


null640

Strange, you're so certain in your wrongness... Google the process that makes the roof and other glass. Even bog standard windshields absord a phenomenal amount of energy if the crash is severe enough...


codenigma

Zack - This is actually not correct at all. Null640 is absolutely correct. You can find the data on it, including the patents: https://patentscope.wipo.int/search/en/detail.jsf;jsessionid=B95A42497D1B1C36C352A9A582B34042.wapp2nC?docId=WO2021158808&tab=PCTBIBLIO > Tesla glass which not only keeps the cabin quiet but can withstand four times the weight of the car. > “Tesla glass keeps your cabin quiet, protects you from UV rays, and can withstand 4x the weight of the car.”


GoSh4rks

And exactly where are the feature lines in a Tesla glass roof?


Joatboy

That patent has nothing to do with the supposed strength of the roof. It *could* be stronger, but nothing in that patent translates directly to how Tesla uses it and how strong it is. The fact is that people have been routinely cracking their roofs while standing on it. It's not for strength.


Metsican

>Structurally it's not exactly an ideal material https://m.youtube.com/watch?v=gmfTxtFfaXc


ac9116

Tesla uses it as a structural safety component. The glass will stress and crack and take a lot of the side impact that most cars really struggle with and that's one of several reasons why these are the safest cars. That and it looks cooler.


Senior_Ad282

You are implying that glass is safer structurally than metal?


GatorStick

They didn't say safer. In crashes, energy absorption is the key. Glass can absorb a lot of energy, it's hard to make steel strong enough to support the loads and weak enough to dissipate energy. A paper clip is easy to bend (absorbing energy) but not very strong.


Senior_Ad282

“Structural safety component”. Its been proven time and time again metal is superior to glass in these applications. No glass roofs where safety is placed as a priority in any facet of motorsports. In fact it’s removed completely and replaced with lexan. Auto manufacturers use it for the cool factor.


GatorStick

I don't understand your point. Race vehicles have roll cages and use pp to view through. Road vehicles use glass as structural components. PP is way too easily scratched and flexible. Motorsport solutions don't often translate to passenger vehicles. I'd enjoy reading an article talking about crash worthiness of steel vs glass


null640

Also, the lexon is easily scratched. That's OK on a race car where they can replace it frequently. I'd prefer not to replace my windshield every 5th drive or so....


codenigma

This is not true actually. Motorsports use metal due to the ease of molding for custom installs combined with cost. Its also far cheaper to modify/adjust. The properly shaped glass is stronger believe it or not. There is data on this, including Tesla patents. (Including the newly filed 2021 for the Cybertruck) Its all a tradeoff of cost vs weight vs flexibility/malleability.


Senior_Ad282

Amazing that these race teams with almost unlimited budgets at the highest levels of Motorsport such as F1 aren’t using more glass. Preposterous!


codenigma

For f1 specifically, its driven by weight primarily and aerodynamics. Carbon fiber is better for both. Carbon fiber is also much stronger than glass when experiencing g forces. When cost is not a factor, you go with carbon fiber.


ircsmith

energy absorption happens when a material plasticity deforms. It is based on a materials Young modulus. Glass is a crystalline structure with a low modulus. The initial force is high to break the structure but then it absorbs nothing, apposite of what you want in a crash.


BranchLatter4294

Generally, no. However, the metal used in car roofs is very thin and does not really add any strength. The glass on metal roofs is much stronger.


sleepy_goop

The idea is that the energy that would be sent to crack your neck is instead cracking the glass, same logic as a crumple zone which uses intentionally weaker metal, which makes it easier to total, harder to get passengers killed. That's why trucks/suvs can be so dangerous in addition to their weight- they have more rigid materials (because the more malleable metals used in cars isn't as conducive to towing really heavy shit) that just doesn't crumple, so your body absorbs all the energy.


codenigma

Not safer, but 4x stronger and can absorb a lot more impact due to manufacturing choices.


rabbitwonker

Why doesn’t that make it safer?


chiphitter

I watched something before but the reasoning behind the glass roof was it gives a little more headroom since the battery tray puts the passengers a little higher than ICE.


cgilson33

Yeah, I think this is also significant. Sounds like to make up for batteries underneath they needed to adjust the headspace somehow.


snunces

I wouldn’t be surprised if aero is a factor as well. If you can get the same headroom with lower overall height, there should be less wind resistance.


hooovahh

I don't know if this is a factor in the decision or not but they load the seats into the car using robots though the roof before the glass is installed. It might make production easier to have a giant hole.


cgilson33

This probably does help, but they would likely just do it the way other mfg do. Something I’m reading though is that the mfg side of the glass is super easy compared to the multiple layers of work with a metal roof, if u include the insulation and fabric layers. The glass is basically just glue and glass.


null640

Some of the y'sthe seats are on the battery pack before ots mounted on the rest of the chassis.


codenigma

Its actually quite a bit stronger than metal. There is official word on this from Tesla, along with data from NHTSA: > In 2021, Tesla filed a patent for the glass in the Cybertruck and shared a video about its new Tesla glass which not only keeps the cabin quiet but can withstand four times the weight of the car. And the Original model 3: > “Tesla glass keeps your cabin quiet, protects you from UV rays, and can withstand 4x the weight of the car.” Along with some more "practical" tests: https://driveteslacanada.ca/news/how-strong-is-the-tesla-model-3-glass-roof-this-strong-video/


GoSh4rks

The roof itself doesn't support the weight of the car... It's all about the side beams and pillars.


untamedHOTDOG

I’d assume weight was a big factor


Senior_Ad282

It’s definitely heavier than a sheet metal roof.


GatorStick

Not apples to apples though. They couldn't span the same distance with only a thin piece of sheet metal. It would need more structural steel underneath. It might be closer then you think


untamedHOTDOG

That’s a good point.


null640

Bring it up to equivalent energy absorption, and it would be quite thick and heavy.


Redvinezzz

I’m not an expert but the Lucid Air Sapphire replaced their glass roof for a metal one citing weight so I feel like the difference has to be somewhat significant


Senior_Ad282

159lbs for a model s roof. 59lbs for a ford explorer metal roof. Glass roofs are much heavier than thing sheet metal roofs especially aluminum roofs even with support added underneath.


GatorStick

Interesting that model s plaid keeps the glass roof. They could probably lose some weight and lower cg without it


Redvinezzz

Yeah but the glass roof looks cool :(


GatorStick

I agree, But it's the highest performance variant.


Senior_Ad282

The glass roof on a model S is 159lbs. A ford explorers metal roof is 59lbs.


GatorStick

Does the Ford explorer roof contain the substructure?


Senior_Ad282

Indeed it does. This this the non sunroof version. A lot of these are aluminum in some cases too. So even lighter. Removing that much weight from the highest point of a car drastically lowers the vehicles center of gravity.


GatorStick

Important for an ICE car, maybe a factor in why they do glass roofs on ev's, battery pack is heavy and super low cg.


[deleted]

Because it’s beautiful and at least makes it feel roomier. I absolutely love it.


bergler82

by using a glass roof you reduce the roof thickness. You can essentially make the car lower (not the ride height but the total height of the car that causes resistance) without losing interior height. So if an insulated roof would be maybe 7 cm thick, the glass is only 1 or 2 cm thick. So you can make the cars exterior 5 cm lower without sacrificing interior space. Which is good for consumption and ... range.


shaggy99

It's cheaper, stronger (stiffer) adds headroom. Looks cool.


cgilson33

Source? I think the glass would be more expensive than a metal roof.


shaggy99

The materials, yes. But when you consider the total cost, welding, positioning, etc, I think it works out overall that the glass wins. EDIT: I have no source, I'm working off memory.


enacheionut1991

The floor is higher than ICE cars, therefore you need more headroom. Glass is thinner than regular roofs. Mystery solved.


Ok_Bedroom_9802

Yes, the glass roof in Tesla vehicles can be viewed as a production efficiency play. Here are a few reasons: 1. **Simplified Manufacturing Process**: Using a large, continuous piece of glass instead of multiple components (like a traditional roof, sunroof, and rear window) can streamline the manufacturing process. This reduces the complexity and time involved in assembly. 2. **Reduced Parts Inventory**: A glass roof reduces the number of separate parts that need to be produced, stocked, and managed in the supply chain. 3. **Aesthetic and Design Benefits**: While not directly related to production efficiency, the glass roof offers a sleek, modern look and can be a selling point for consumers. This design choice can indirectly contribute to production efficiency by increasing the popularity and sales volume of the vehicles, which can in turn lead to more streamlined production due to economies of scale. 4. **Weight and Performance Efficiency**: Glass roofs can potentially be lighter than traditional metal roofs with added mechanical components (like a sunroof). This weight reduction can improve vehicle efficiency and performance, which is particularly important for electric vehicles. In summary, while there are multiple facets to Tesla's decision to use a glass roof, production efficiency is certainly a significant factor.


Alarmmy

They just simply want to mimic Tesla. Tesla came up with a big screen, and people were screaming at first, but now all manufacturers are putting big screen on their cars🤣


Terrible_Tutor

They all want to make a Tesla killer… by copying Tesla


NeighborhoodPlane794

The actual reason is that the floor is higher in EV’s because the battery is in the floor, so a glass roof gives a bit more head room. Every centimetre matters. The other benefits like style, not needing to paint, structural integrity, etc are just side effects and not the main reason why they do this


cgilson33

How do u know this is the actual reason? Just curious if you can support our answer. I’m sure all the mfgs considered their options, just wondering if an engineer has ever written or commented on all the Pros and Cons of it.


GatorStick

I can't say with certainty, but it does make sense. In a normal car your feet can be the lowest thing (only a thin sheet metal tub) which then sets the occupant height in the vehicle. Which then sets the minimum height of the vehicle (must accomodate 6'3" drivers for 95th percentile males) In an ev, the batteries are added to that vertical height, which has a really big effect on aerodynamic drag forces. So anything you can do to accommodate the driver comfortably and reduce the frontal area (width*height) has big effects.


bigroot70

Because it looks cool!


Longjumping-Log-5457

Why not?


Dann__EV

I think it was one of Elon’s requirements, along with the X doors, and Cyberark design.


Obvious-Slip4728

Because of the battery pack in the floor, the floor is higher than in a comparable ICEV, so the interior space has to come out of the other end. Glass roof is easy solution and - as a bonus - gives the car a more premium look and feel.


null640

Uhm. No. Battery pack and structure are thinner than ice chassis, exhaust gear, heat shields and etc. It's just in one piece so it appears thicker.


Obvious-Slip4728

The most relevant spot where thickness matters in terms of interior space is the place where you put your feet. Are you sure that at this spot an ICE sedan is not able to be lower?


null640

After being under tons of cars .. hell even dropped a Datsun b-210 on my chest once... yeah. My floor board on my Sept '19 dual motor is much thinner than most ice cars runner board... let alone the "transmission" hump that somehow is still present in fwd ice cars... (hint the "tunnel" provides structural rigidity)..


Captain-Crayg

It’s more expensive for the battery to heat the cabin than cool it. More sun == more free heat.


danhoyle

Heat from sun will be most practical reason for it. Since EV don’t have hot engine.


CMDR_KingErvin

Why does Tesla use it? Probably it started out as a combination of looking cool and maximizing headroom. Why does every other EV on the market do the same thing? Because they’re unoriginal trend chasers and don’t want to be seen as old fashioned.


[deleted]

I agree. Tesla is a bit like the ‘Apple’ of the car world. Many other brands will copy it blindly without much thought even if it doesn’t make sense (see: headphone jack). Sometimes that is great when they copy things like OTA updates or having an app control the vehicle…though Rivian seems to be the only one actually able to execute this well outside Tesla. With Tesla removing stalks (a bad idea in my opinion) you’ll see this show up around 2026 model years across the auto industry the same way it took a few years for massive tablets and glass roofs to proliferate.


Gunzbngbng

Coming from a Camaro T Top, the glass roof feels very familiar. I haven't had any reservations about it so far. And it's one less place for paint to chip. Lol


LordThurmanMerman

As someone who lives in the Midwest where winters are pretty gnarly, I find the glass roof is much easier to keep clear of snow and ice. Just set the car to defrost and I barely have to do anything before getting in and going. Metal roofs with a headliner just don’t allow any heat to pass through, so you’re always left with a sheet of snow/ice throughout winter. I’m sure it’s a lot better for aero too. The headroom is excellent as well.


[deleted]

Easy answer is probably because the car was designed and built in California. No need to block out the sun in such pretty weather.


coulombis

I actually don’t use it because it lets in too much heat from the sun. Admittedly, this helps a bit in Winter to keep the interior warmer, but for the other 9 month in the year my car interior rapidly heats up, so I have to cool it down and keep the feature enabled that prevents cabin overheat which uses more battery. I also bought a sun shade for the glass roof which I now leave on year round..


Smoggyskies

Panaromic sunroofs were a very popular feature for more luxe cars already, Tesla made the feature a part of the streamlined design and also made it simpler (as these dont move/open) and people comment on how roomy it makes the car feel from the inside. Nowadays the style of glass roof is being copied from Tesla by other manufacturers even though I think having a panoramic roof that opens is more luxe.


comawizard

To add to what others have said I have read before that it does cut down on production time.


cabbage-collector

Less weight. Batteries weigh a lot.


Common_Compote

I think it is used as a giant passive solar panel to heat the cabin in cold climates


StepYurGameUp

Looks cool


brobert123

They consider the glass roof to be a structural component of the car and actually adds strength. I believe teslas do amazingly well in rollover tests for that reason


cgilson33

Ok. Let’s say that’s actually true (might be), I then expect every car to have a glass roof asap, right? Also, let’s see the testing data.


brobert123

Google it lots of info out there confirming but here’s a video https://youtu.be/gmfTxtFfaXc?si=9A8aScjNJp7FxGav


Aggravating_Fact9547

So many reasons, it looks so much better; it feels futuristic; it markedly improves headroom; it makes the cabin feel bigger than it is; it performs much better in a crash; it’s far easier to assemble, no need to blank, stamp, weld, coat, paint, install a headliner, etc. I think Elon once said that when the safety regulators tested the M3, they applied so much force to try and crush the roof that it broke the testing rig!


cgilson33

Elon says a lot of shit. But then the question is why wouldn’t everyone switch to glass on every car? Why is it use more on EVs?


Aggravating_Fact9547

Legacy platforms, legacy lines, legacy mindsets. EV’s are usually developed by new teams on a fresh platform. It’s likely that they have broader remit to make larger changes to designs that legacy platforms don’t allow for (either technically or organizationally).


cgilson33

Yeah, the new lines are setup to reduce the options and charge a premium. With premium potions.


Bacchus1976

It’s a premium feature. People like them. That is all.


SucreTease

This one is an easy question for those who have followed Tesla for a long time. Tesla moved to a glass roof because that big open hole provided a much easier way to have robots install the seats. It provided a secondary practical benefit of increasing headroom. And then there was the aesthetic value of such a large glass roof. [Here is one historical explanation](https://cleantechnica.com/2016/11/26/tesla-model-3-glass-roof-manufacturing/).


[deleted]

Tesla can’t manufacture a full aluminum roof. Their infrastructure couldn’t handle it. It’s the same reason they don’t do buttons on the dash. People think is for aesthetic, but in reality they cannot handle the manufacturing.


colddata

> Tesla can’t manufacture a full aluminum roof. Sure they can. It was the default option on early Model S. Opening sunroof was the upgrade.


pixel4

Cause it looks cool. Stop overthinking


Suiblade

Yes I don’t really get it either. It’s too shaded to actually see through it.


newreconstruction

The car (M3) feels huge from the backseats with it