New answers tagged design
Sariel's assembly video shows that he ends up not using those 6 studs for the car assembly but wait! if you scroll down into the comments: he explains that the pieces are used for the B-model:
There are all kinds of situations where the front and rear axle may not rotate at the same speed. Imagine for example a bicycle taking a turn while remaining vertical. When viewed from the top (using a planar projection), the bicycle rotates around a point that's at the intersection between lines perpendicular to each wheel. Here's an ASCII-art illustration ...
Well, the center diff allows the front and rear axles to turn at different speeds, which is useful to put less stress on drivetrain parts that are constantly moving around. However, for a Lego model it is probably not required, since it most likely would not move at speeds required to necessitate one. Building one in would add realism, but you would need to ...
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