10 ms·

Any impact that damages any part of the massive cast unibody. Compared to stamped metal, a cast metal part is brittle under impact and is far more likely to cra

Any impact that damages any part of the massive cast unibody. Compared to stamped metal, a cast metal part is brittle under impact and is far more likely to crack rather than deforming. That can be good for safety ratings - in a collision the cast metal will crack, absorbing and dispersing the impact. However, when most of the car's structure is a single piece of cast metal there is no viable way to replace just the cracked piece. Yes, you can cut and weld it, in theory. But aluminum is difficult to weld and cast metals are extremely difficult to weld. Repairing cast aluminum is a highly specialized skill that is unusual even among professional metalworkers.

skullone 3y ago
Unibody cars are already totaled out for frame damage pretty often. It can be very hard to properly repair structural and safety elements of a modern unibody. Not to say you won't see it on the road, but it will be a salvage/reconstructed title that won't carrying comprehensive insurance ever again.
- pixl97 3y ago
  Yea, I can't imagine getting all the safety systems working again in a modern car after a crash. In older cars it was easy to chop them in two and weld them together however you wanted. But these days with the concepts where the engine compartment and trunk are crush zones and the passenger compartment is rigid so they occupants don't get crushed, there is a ton of non visible damage in even minor impacts.
- codeTired 3y ago
  In order to get a salvage title the car needs to be totaled. Insurance doesn’t care if there is frame damage. It only cares how much the car is worth, how much it’s going to cost to fix and how much it’s worth at an auction in its current state. They run the numbers and decide if they are fixing or totaling the car. There is a reason tesla is expensive to insure.
  - skullone 3y ago
    It's also liability. If insurance determines frame damage, they're inclined to often total it and settle with you. You ain't getting that car unless you buy it back. I know this since I've worked in insurance, they don't want to be liable if the car doesn't perform to manufacturers specifications while driving or another accident. Initial repair/value cost is a determining factor yes, but doubly so future liability. Take it to their preferred shop, repair is inadequate, fails to perform while driving = they're liable for way more than initially.
bryanlarsen 3y ago
But that's not minor damage, it's the sort of damage that will bend the frame on a normal vehicle. While it's possible to repair a car with a bent frame, they're typically written off. And if they are repaired, they're rarely the same car as they were before the accident.
- klodolph 3y ago
  n=1 but I’ve been in collisions with unibody cars, and they were not written off just because the frame was bent. They were repaired. Granted, these were fender benders. Not serious collisions.
  - pixl97 3y ago
    Then one would assume that the cast components would not have been broken either. The crumple zones in modern cars hide a lot of serious damage in a minor appearing accident. My sister in law was hit a few months ago and I was able to drive the car home with what just appeared to be a missing tail light and had to tie down the trunk. When the auto shop looked at it they could see serious warping and bends at welds all over places in the unibody that would cost more to repair than the car is worth.
  - CharlesW 3y ago
    > n=1 but I’ve been in collisions with unibody cars, and they were not written off just because the frame was bent. You might've missed this earlier comment by @unregistereddev: "Compared to stamped metal, a cast metal part is brittle under impact and is far more likely to crack rather than deforming." In Tesla's case specifically, this isn't just hypothetical: https://www.thedrive.com/news/tesla-model-y-owner-finds-scary-cracks-in-gigacast-front-end https://www.thedrive.com/news/tesla-model-y-owner-finds-scar...
- unregistereddev 3y ago
  Not necessarily. The unibody "frame" is a much smaller piece than what Tesla has combined into a single component. For example, dropping and replacing a bent subframe (the part that typically holds the front suspension) will cost 2-3 thousand dollars on a normal vehicle - but damaging the same component in this Tesla design requires replacing the whole "gigacasting".
xenadu02 3y ago
People weld cast metal parts all the time. Same for aluminum. The process is just less familiar... aluminum wire is softer than steel so you can't just load it into the MIG and go - you usually want a wire feed gun that puts the spool directly on the back of the MIG gun. And you would usually use Argon shield gas (rather than C25 or C100 for stuff like mild steel). Tesla's gigacasting cars are roughly as repairable as any other modern car. Lower speed collisions can sometimes be repaired. The repair may not leave it as structurally sound or with the same collision resistance. The older the car gets the more likely it is to be totaled even in such a lower speed collision because these kinds of repairs are labor intensive. Medium and high speed collisions are always a full loss event. That's a deliberate design decision to sacrifice the car (eg crumple zones) to protect the passengers. Insurance totaling out Teslas is to some degree an early adopter problem. Parts are less available, service centers with experience may not exist in your area, third party service manuals haven't been published, etc. These things make the cars more expensive to repair. All of these issues are rapidly improving but it should be obvious that they aren't a 100 year old car maker so their network of spare parts and repair shops will smart out smaller.

skullone 3y ago

Unibody cars are already totaled out for frame damage pretty often. It can be very hard to properly repair structural and safety elements of a modern unibody. Not to say you won't see it on the road, but it will be a salvage/reconstructed title that won't carrying comprehensive insurance ever again.

pixl97 3y ago
Yea, I can't imagine getting all the safety systems working again in a modern car after a crash. In older cars it was easy to chop them in two and weld them together however you wanted. But these days with the concepts where the engine compartment and trunk are crush zones and the passenger compartment is rigid so they occupants don't get crushed, there is a ton of non visible damage in even minor impacts.
codeTired 3y ago
In order to get a salvage title the car needs to be totaled. Insurance doesn’t care if there is frame damage. It only cares how much the car is worth, how much it’s going to cost to fix and how much it’s worth at an auction in its current state. They run the numbers and decide if they are fixing or totaling the car. There is a reason tesla is expensive to insure.
- skullone 3y ago
  It's also liability. If insurance determines frame damage, they're inclined to often total it and settle with you. You ain't getting that car unless you buy it back. I know this since I've worked in insurance, they don't want to be liable if the car doesn't perform to manufacturers specifications while driving or another accident. Initial repair/value cost is a determining factor yes, but doubly so future liability. Take it to their preferred shop, repair is inadequate, fails to perform while driving = they're liable for way more than initially.

bryanlarsen 3y ago

But that's not minor damage, it's the sort of damage that will bend the frame on a normal vehicle. While it's possible to repair a car with a bent frame, they're typically written off. And if they are repaired, they're rarely the same car as they were before the accident.

klodolph 3y ago
n=1 but I’ve been in collisions with unibody cars, and they were not written off just because the frame was bent. They were repaired. Granted, these were fender benders. Not serious collisions.
- pixl97 3y ago
  Then one would assume that the cast components would not have been broken either. The crumple zones in modern cars hide a lot of serious damage in a minor appearing accident. My sister in law was hit a few months ago and I was able to drive the car home with what just appeared to be a missing tail light and had to tie down the trunk. When the auto shop looked at it they could see serious warping and bends at welds all over places in the unibody that would cost more to repair than the car is worth.
- CharlesW 3y ago
  > n=1 but I’ve been in collisions with unibody cars, and they were not written off just because the frame was bent. You might've missed this earlier comment by @unregistereddev: "Compared to stamped metal, a cast metal part is brittle under impact and is far more likely to crack rather than deforming." In Tesla's case specifically, this isn't just hypothetical: https://www.thedrive.com/news/tesla-model-y-owner-finds-scary-cracks-in-gigacast-front-end https://www.thedrive.com/news/tesla-model-y-owner-finds-scar...
unregistereddev 3y ago
Not necessarily. The unibody "frame" is a much smaller piece than what Tesla has combined into a single component. For example, dropping and replacing a bent subframe (the part that typically holds the front suspension) will cost 2-3 thousand dollars on a normal vehicle - but damaging the same component in this Tesla design requires replacing the whole "gigacasting".

xenadu02 3y ago

People weld cast metal parts all the time. Same for aluminum. The process is just less familiar... aluminum wire is softer than steel so you can't just load it into the MIG and go - you usually want a wire feed gun that puts the spool directly on the back of the MIG gun. And you would usually use Argon shield gas (rather than C25 or C100 for stuff like mild steel). Tesla's gigacasting cars are roughly as repairable as any other modern car. Lower speed collisions can sometimes be repaired. The repair may not leave it as structurally sound or with the same collision resistance. The older the car gets the more likely it is to be totaled even in such a lower speed collision because these kinds of repairs are labor intensive. Medium and high speed collisions are always a full loss event. That's a deliberate design decision to sacrifice the car (eg crumple zones) to protect the passengers. Insurance totaling out Teslas is to some degree an early adopter problem. Parts are less available, service centers with experience may not exist in your area, third party service manuals haven't been published, etc. These things make the cars more expensive to repair. All of these issues are rapidly improving but it should be obvious that they aren't a 100 year old car maker so their network of spare parts and repair shops will smart out smaller.