Originally Posted by roadbuzz
It's probably more about product differentiation than manufacturing cost. They want you to pay more for the lighter stuff, and making the product lines too similar eliminates reasons for upgrading.
Actually it does cost more, a few things are different. I don't know how much.
The spokes are very different and more complicated, with a spinning nipple as part of the spoke. The threaded hole in the inner rim is made by having the material so hot that it is in a molten state and a tap threads the hole and forms a collar at the same time. The tap has to come from the inside diameter out.
The rim is very different too.
The tooling is a lot more complicated and the parts are not standard parts.