The model Y, as delivered today, already has a very large casting in the rear: There are many sources out there describing it, and how it simplifies model Y ass

The model Y, as delivered today, already has a very large casting in the rear: There are many sources out there describing it, and how it simplifies model Y assembly compared to the otherwise rather similar model 3. What they are describing here is to go further with a process they are already doing very advanced work on in production cars. They might have problems. They can fail altogether. Maybe it turns out to be a bad idea anyway, but I do not expect Tesla engineering to be just naive at this. As for why Fremont is the last place to get the changes, it seems to me that there are simpler reasons: That factory is the main source for Teslas on the road today, and it operates more or less at capacity. Adding a new process would slow it down, at least temporarily. The Berlin and Texas factories, AFAIK, have yet to start operation, so they are good places to try something new, given that Tesla is selling the cars about as fast as they can make them. This is how a lot of the industry does things: Make your new facilities have the latest and greatest, and only retrofit the old ones when it makes economic sense to dismantle the older process. No matter what the theoretical savings might be for a new casting vs so much soldering and assembly, the old process is making cars, today, so decommissioning it is not as good a value proposition as just not even trying the old process in a new facility.