[Fortune] Elon Musk's Tesla reportedly halts Cybertruck deliveries as owners complain of metal sides falling off

[u/ShirlLotJack]

https://fortune.com/2025/03/14/elon-musk-tesla-cybertruck-delivery-halt-owners-complain-of-metal-sides-falling-off/

[u/caffeine-junkie]

Or how aluminum does not have an endurance limit, meaning it will fail when put under enough stress cycles. So building things like the frame or other stress structures out of it, like with the cybertruck, can be a bad idea.

Also the adhesive is not only being used on dissimilar metals , the cybertruck also uses it to hold similar metals together until they can be fastened together.... instead of you know, welds.

[u/if-we-all-did-this → u/caffeine-junkie]

Kinda, but also not. I used to be the joining & sealing design engineer for Jaguar Land Rover. All our Jaguars are all aluminium body structures, and met all crash behaviour requirements with no steel in the body.

The bigger/heavier Land Rovers have the addition of a pair of very thick boron steel reinforcement plates to surpass the notoriously tricky "small offset impact" test.

Work with the manufacturers to select the optimal adhesives, carefully control their application, & the cleanliness of the substrates, and you've got a joint (between differing materials even) which is stronger, more robust, and (most importantly) more predictable than many other joining techniques.

Tesla's "move fast & break stuff" approach is incongruous to the meticulous & methodical approach required of material science & chemistry, underpinning automotive structural adhesives.

[u/Superbead → u/if-we-all-did-this]

The bigger/heavier Land Rovers have the addition of a pair of very thick boron steel reinforcement plates to surpass the notoriously tricky "small offset impact" test.

This is interesting.

1. Are these mounted in front of the front wheels in order to deflect the vehicle away from the impact?

2. Without meaning to be personally accusative—a lot of Reddit gushes about engineering saving lives with crumple zones and so forth, but it looks to me like most safety developments are fairly reluctant reactions to new test standards, rather than borne of benevolence. Had the small overlap test never been a thing, do you expect those plates would've been designed in anyway?

[u/if-we-all-did-this → u/Superbead]

You've hit on one of my major frustrations with the company, and part of the reason I left when I did.

The boron steel plates sit inside the front foot wells of the L663 defenders (which were the first models off the D7x platform, so I'm assuming they're carried over to the latest Rangr Rover & RRSport).

My problem is that this was a palliative action in response to the early crash footage of the defender (without the plates) doing the small offset crash. The camera was on the seat base looking forward, and when the car hit the block, it drove the road wheel back, bursting through the joins in the footwear and hitting he seat. Yup, tyre tread pattern on the seat bolster... where your legs are now painted.

This was fine, this is why we do the early prototype crashes, to learn, test, and validate our simulated impacts. What was not fine is thst these plates were (& I'm assuming still are?) ONLY fitted to US market defenders, where small offset is a legal requirement. At [iirc] ~£35 per car, the cost was deemed too much for UK/ROTW markets. So essentially JLR values their customer's legs as not worth £35... on a car making insane profit.

Part of me hopes that there is a class action at some point, and pressure them to do the right thing, however for that to come about, someone would need to crash one, loose their legs, and then the investigation show that [obviously] JLR knew about the issue, and didn't sort it for that market, and for a judge to not accept their defence of "accidents happen, we built the vehicle to meet all legal crash requirements".

[u/Superbead → u/if-we-all-did-this]

Wow, thanks. I appreciate the high-effort answer, and respect due for sticking to your principles. It sounds like high time the other big testing agencies brought in the small offset test as well. It'd be interesting to see the results. I remember when the IIHS introduced theirs, and the wheels entering the footwells seemed to be the biggest issue of all. I wonder if that would make a reappearance across the board in other markets.

On the subject, I remember when the IIHS began their passenger-side small offset tests, and at least one manufacturer (can't remember who) was caught with their pants down for having gamed the test driver's-side only. They'd added some kind of high-strength steel outrigger to only one side of the transverse structural element that spans the frame rails just behind the bumper. Talk about cheapskating.

[u/if-we-all-did-this → u/Superbead]

I can absolutely imagine them gaming the test, it's a common attitude I'd love to see evolve out of automotive design, but as we all saw from the emissions scandal with VW, we're a long way from there yet.

Interestingly, while VW were getting the flack, lots of manufacturers were guilty of similar. My favourite was BMW; we found that their Z4 engines would enter a different map (ecu goverened state of engine tune, fuel consumption, & emissions parameters) when the on board GPS knew it was near one of the two UK testing laboratories, then resort to its regular settings once far enough a way.

I've also head of harder tyres being used for the fuel consumption test vehicle thst are moulded to look exactly like the softer/cheaper/grippier tyres used on the actual production cars etc, meaning collusion between manufacturers & suppliers.

As for small offset, personally I think it should be across all markets. Smashing a car into a wall is great as a data point with minimal variables, but in the real world people either steer away from a solid impacting object, or strike posts, guard rails, trees, parked cars etc. Small offset is far more realistic, and drives continuous improvements.

Volvo are the only manufacturer in my expirience who really get ahead of safety requirements, and they design their chassis leg structures like an inverted V, or snow plow, so the vehicle deflects from the small offset impact, instead of trying to absorb on of that kinetic chaos. Simple, smart, and a contributing indicator as to why (as of ~5 years ago when I left) no passenger of a Volvo XC90 has ever been killed in an accident. Imagine if all manufacturers strove for that performance too?

[u/Not_FinancialAdvice → u/if-we-all-did-this]

Lotus also used a bonded aluminum chassis for many of their models and structural failure hasn't really been a thing.

[u/if-we-all-did-this → u/Not_FinancialAdvice]

Yup. Plus, most Lotus models are small production volumes, so crash requirements etc and different, or don't apply whatsoever.

Edit: I also love your name is "not financial advice" when talking about a Lotus!

[u/AutoModerator → u/if-we-all-did-this]

PUT YOUR HANDS UP if-we-all-did-this!!! POLICE ARE ENROUTE! PREPARE TO BE BOOKED FOR PROVIDING ILLEGAL FINANCIAL ADVICE!

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/Freefallisfun → u/if-we-all-did-this]

Cool. I’m interested what you think of epoxies. My company uses them as a “containment”, which then becomes how we do it. Thus, fuckin glue everywhere instead of making proper fastenings.

[u/if-we-all-did-this → u/Freefallisfun]

Epoxies can be great, but again it really depends on surface, Ra value of surface roughness, contaminants, temps, humidity, duty cycles, gap between surfaces (e.g. some adhesives are strongest at 0.3mm thick, and performance drops off significantly 1mm either side of that) etc etc.

Get it right, and get it right consistently, and you're all good.

Get it wrong, and you have a situation like on the F-Type.

F-Type was a small production 2 seater coupe, and one of the options was to swap the aluminium roof panel for a sexy AF carbon fibre roof panel.

This CF roof panel was bonded in place with a two part Epoxy, applied with a heated gun, but by hand (rather than robotised, due to the super low volumes). But the gun hat to be turned on and heated hours before use, and the Epoxy wasn't tested for contract cooling/heating cycles before use etc, so there were loads of variables to manage.

By hand application also meant inconsistencies, and CF is a pain to bond to anyway (I even worked on a project into the viability of plasma etching CF to give the Epoxy something to adhere to), so variable thickness, or an inconsistent bead meant an inconsistent performance.

We had one such CF roof fail on a car. Guy was driving at a fast but legal speed, roof flew off, very nearly decapitating a pedestrian. This rung alarm bells for us back at the factory as the incident occurred in Monocco... to a very high profile owner (football club owning levels of wealth), and him decapitating a pedestrian in such a tragic way would certainly have been international news.

So yeah, Epoxy can be great, but only if the system/lifetime level design for it's application & use are also great.

[u/EndlessB → u/if-we-all-did-this]

Fuck it’s cool when you read a comment on reddit from someone who actually seems to know what they are talking about

[u/marino1310 → u/caffeine-junkie]

The fact the frame is cast aluminum is even better. Cast aluminum is brittle and does not like to bend. It’s a good thing frames don’t have to deal with flexing or shock loads ever

[u/DirkWisely → u/caffeine-junkie]

We build fucking airplanes out of aluminum. I know you read a comment or watched a YouTube video and wanted to sound smart, but Jesus Christ.

[u/Ithrazel → u/caffeine-junkie]

Audi A8, Audi A2, Jaguar XJ were built for a long time with aluminium frames/chassis, not proven to be in any way problematic so far, just expensive to make.

[u/ChunkyHabeneroSalsa → u/Ithrazel]

Weren't corvettes also built with aluminum frames?

[u/squngy → u/caffeine-junkie]

The way those things are made, they will fall apart looong before the endurance limit of aluminium becomes an issue