What are you referring to with one piece carbon fiber. The new Xcurve frame still has the same 4 carbon fiber composite stays, but the stays are triangular in shape instead of round. The Krux frame also has 4 carbon staysIf your looking at the new frame x-curve it’s only going to be a couple ounces (9 oz). The new frame is made with a one piece carbon fiber rather than the two piece in the OG. I would second the xcurve is way better for comfort.