Hacker News Reader

Comment by dweekly | Hacker News Reader

It's exciting, and at the same time it makes clear that even small accidents may cause a complete write off of the vehicle due to the unrepairability of cars manufactured with this technique.

View on HN

The cast is only the interiour frame. If that gets damaged, the car is a write-off anyway. The outer bodywork can be repaired of course.

I wonder if the Cybertruck fails in this regard.

We don't know much about the construction of the Cybertruck. But one would assume that the center part of the body gives the structural integrety, while the outer parts are the crash and crumple zones. This should make the Cybertruck repairable, especially as it is just steel and no aluminium involved.

It is disappointing that Tesla uses much of its engineering prowess to design products that are inherently difficult for owners or small shops to modify, maintain, or repair. Taken directly from Apple's playbook.

If Musk wants to have another glory moment, he should make people design modular couplings for parts

They are now in the insurance business and Musk has already stated this will drive them to produce cars that can be repaired more cheaply. I cited his statement on the earnings call elsewhere in this thread.

Musk says many things

It is a business + an insurance business. They are highly incentivized to drive down costs and have proven that constantly.

he says many things and his timelines are completely off but IMO he delivers

Apple didn't do it to prevent repair, but because you can build a better product by making things non-standard, closer fitting, single piece machined, etc.

Tesla is probably doing the same.

Remember a good number of repairs Tesla will end up paying for - through various warranty schemes - so they care about repairability too, just to a lesser extent than they care about product performance and cost.

You need to understand Elon to understand that. He talks ton about sustainability. But what he means by that, is sustaining lifestyle of rich people, while feeling good about themselves.

He's actively against public transport (which is by far most ecological), pursuing dreams of living on Mars (which is unpractical on so many levels, that if it'll be ever complete, it'll be trip of lifetime to fifthly rich people), building expensive toy cars (car that does 0-60 in less than 6s? who would even want that?) and many more.

How can two of Elons biggest projects be public transportation oriented while you claim he's against it?

Which ones?

Boring company, aka, private tunnels for Model 3/S/X (https://electrek.co/2020/07/20/elon-musk-boring-company-tesl...)? It's as much of a public transportation as Uber.

Hyperloop, aka vaporware?

> "Tesla uses much of its engineering prowess to design products that are inherently difficult for owners or small shops to modify, maintain, or repair."

Teslas (especially the Model 3 and Y) are not inherently difficult to repair. The problem is that Tesla's restrictive policies make it difficult for individuals to access the documentation and parts to do so.

The reduction in size/complexity at Tesla/Apple scale may actually be an overall benefit.

Thought experiment: Imagine that the overall material required is cut by 10-20% by tons of optimizations and reductions. That means the supply chain and associated energy/costs vanish. If you have a failure rate of less than that (probably much less) scrapping is likely still better.

Unibody would cut shell materials by 10-20% but there are many other car parts like interior, battery. So entire cut rate won't so high.

Also dropping a broken car and building a new car takes manufacturing costs.

I'm talking about every optimization that reduces repairability. While I'd prefer to be able to fix things, just producing and shipping a whole new unit to a small subset may be less wasteful overall (at that scale) than designing for repairability.

All of these things are tradeoffs. How much worse of a product would you accept in exchange for repairability?

I'm not even sure there's a tradeoff here, since bending a frame of any car is bad news whether or not its one piece.

Do mechanics typically replace large parts of the frame? I thought that if it was damaged, the car's scrapped anyways.

If say, the front is damaged, a front end from a donor car can be welded on

Salvage mechanics operating on salvage title cars do.

What mechanics do and what insurers pay for are orthogonal.

It's not unusual for mechanics to buy newly totaled cars at their salvage value as a convenient exit to the owner, and either rebuild the vehicle or part it out as a side hustle. A repaired salvage vehicle is eligible for a rebuilt title in some states.

Sure, body-on-frame cars (before the early 1960s) were easy to weld back into shape.

With unibody cars, that doesn't work anymore. Body shops have frame racks to pull steel cars back into shape. That works if the car isn't too bent and your standards aren't too high.

Aluminum unibodies don't respond well to bending so yes... If the frame is tweaked enough to screw up the wheel track, that's probably the end of the car. Maybe find a flood car with a good frame and swap everything over. This is true whether the car's body is a single casting or built up by welding 70 pieces together.

Insurance companies frequently “write off” cars with major damage that would cost more (or nearly) to repair. They generally don’t scrap them, but then sell them at salvage auctions. They are then bought and repaired by people/companies who specialize in fixing up salvage title vehicles. They are then resold (with a salvage title)...generally you should try to avoid anything with a salvage title as they tend to be fixed as cheaply as humanly possible in order to turn a profit.

Toyota replaced the entire frames on a bunch of Tacomas maybe ~10 years ago. So yeah, but obviously not a fun thing to do.

On the model 3/Y, the rear casting will only get damaged in most severe collisions.

We'll see. It makes doing salvage titles a lot easier if you can harvest one good frame casting and then pull from a bunch of other vehicles the other needed parts.

It is also an open question on what it would cost to make this casting as a repair part.

Agreed. Sounds like the Lotus Elise, where if the extruded/bonded aluminum chassis is damaged, the repair procedure is basically "remove everything from the chassis and swap it to a new chassis."

Reply on news.ycombinator.com