Frame: For starters, the frame now features a descending gusset at the top tube/seat tube junction, something mildly reminiscent of the Cervelo P5. The Kamm Virtual Foil (KVF) Kammtail tubeset uses remains throughout the frame (the lopped-off "virtual" trailing edge "curves" along with windflow) but takes on a slightly changed shape with a 5:1 airfoil ratio.
The seat tube also fairs the rear wheel to a much greater degree than it did before, curving on radius with the rear wheel from bottom bracket to the seat stays.
In lieu of a vertically affixed wedge bolt that secured the seat post, the new Speed Concept appears to have horizontally loaded bolts that forward-load the post from the back of the frame.
The redesign results in a frame that Trek claims is 437 grams lighter than its predecessor.
Fork: The SC KVF carbon fiber fork will be available in two iterations: a deep 6:1 ratio aero tri version (which Trek says maintains air attachment without stall from 2.5 to 12.5 degrees of yaw), and a shallower, UCI-legal version for its ProTour teams like RadioShack.
Aero bars: This is a key engineering advance that is a first to market: a single tower that raises the base bar aloft for aero bar pad placement. The aero bar extensions themselves emanate from a singular, central bracket arm. The result is an aero bar without individual left and right pad brackets. The centralization of the affixment of aero bar to frame, Trek says, carves 30 percent of its frontal area.
Brakes: The front and rear brakes take on the same general function and design, down to the cover for the front brake. The biggest advance is the use the "Speed Fin" below the bottom bracket on triathlon bikes, which, on top of serving as a brake stiffener, the upside-down dorsal fin serves to act as a leading-edge fairing for the rear tire and wheel. UCI bikes will have option to install a brake stiffener absent the trailing fin.