This bicycle is built out of aluminum, features a carbon fiber frame, and is infused with the Domane class spirit; the ...
It's 75 pounds with some 10-15 pounds in weight savings over a comparable aluminum frame, per Roberson. Part of that is explained by the Hero being a big bike capable of carrying riders of all sizes.
Aluminum frame manufacturing puts out almost the same carbon emissions as carbon fiber? Trek's setting out to change that.