[lisper]

I understand they're in sniper mode, and I understand why the Model S is the size it is. What I don't understand is why the Model X (http://www.teslamotors.com/modelx) is the size it is. They're going to have two seven-passenger vehicles and zero four-passenger vehicles. That doesn't seem like the right way to diversify.

[MikeCapone]

The Model X is built on top of the Model S platform. That's probably why.

Making it smaller would probably require a lot more complex engineering and tradeoffs when it comes to the powertrain/batteries/etc.

It's actually very smart because they are leveraging all the work they have done for the Model S and getting another model out of it. Elon Musk has said in interviews that the Model S was actually over 90% new parts, which made it very complex to design and get the supply chain going. If the Model X has a significantly lower number of new parts, that'll make a big difference to the bottom line and time to market.

[lisper]

Ah. Well, I suppose that makes a certain amount of sense. But it does leave me wondering how hard it can be to shorten the wheel base. The battery pack already comes in different sizes so they must have that figured out. There's no drive shaft or transmission. It's hard for me to imagine that making the platform shorter is that much harder than designing a whole new body.

[kbenson]

It probably requires re-tooling their assembly line. One of the main purposes of the Model S is to scale the assembly system.

[jnw2]

Elon has five children. Getting Elon + 5 children into a Tesla is a key goal, and presumably his smallest child is going to outgrow the optional rear facing seats in the Model S at some point...