Wheel Construction
Three piece wheels have a spoke section and two rim sections; an inner and an outer. Again, the rim portions are typically forged. The benefit of this construction is the ability to highly customize width & offset. By making the wheel modular, you can produce a much larger array of diameter/width/offset options with fewer manufactured components. This greater flexibility lets the manufacturer provide fitment for tricky situations (e.g., the need to build a wheel that fits over large brake components).
At least that's my understanding.



