With its combination of HED's stable, bullet-shaped rim cross section and the sweet-spot aerodynamics of a 46mm depth, HED's Jet 4 Plus Black Carbon Disc Brake Wheelset may be the ideal racing wheels for any course. The durability of the aluminum spine/carbon fiber fairing construction and the convenience of clinchers expand the Jet 4's capabilities to include everyday use as a training wheelset, too. Whether racing, training, or sportiving, though, the undeniable quality of disc braking takes the original Jet 4's focus on safe, reliable stopping to whole new levels.
While the aluminum rim on Jet wheels originally addressed carbon's poor braking by providing an alloy track, the Jet 4s with disc brakes do away with rim braking altogether. Compared to even the braking surface on HED's Black models, the disc-equipped Black Disc wheels enjoy stopping power that modulates better, grabs with more consistency, and virtually ensures that the Jet 6s will never violently deform because they hit the glass transition temperature as a result of a long, hot descent.
While the new road disc technology may be responsible for stopping a cyclist on these wheels, their strongest selling point is definitely the boost they provide while they're going. As you'd expect from rims of this depth, the wheels love to hold speed after they're spun up. HED also knows that faster speeds require a heightened sense of control that's often at odds with aerodynamic rims, so it developed Stability Control Technology (SCT), which reduces lateral forces applied to the rims at 0-15 degrees of yaw. Combined with the relative stability of a sub-50mm fairing, the addition of SCT nets stability that doesn't quite rival a traditional aluminum box section but won't through you around like a true NACA air foil shape.
The rims' aerodynamic savings are compounded by a reduction in the rolling resistance because of the Jet 4's 25mm wide C2 rims. C2 rims increase the tire's volume and contact patch for lower rolling resistance, more grip in corners, and a more vertically-oriented side wall that is better able to deform around irregularities in the road surface — all of which translates to being able to run a lower PSI for increased comfort without sacrificing efficiency. The tire shape also means the transition air makes from the edge of the tread to the end of the rim is smoother, resulting in still less aerodynamic drag.