With every wheelset, there is some sort of compromise. If it's a super deep-dish, it will be expensive and it may not handle well in the wind. If it's a box rim, well, it'll be inexpensive, but most likely heavy. The HED Jet 4 Clincher Wheelset is designed to minimize compromises to give you a lightweight rim, with an aerodynamic advantage without having to refinance your home.
The Jet 4 rims are 46mm deep, which is about double the depth of the HED Belgium series (or most traditional hybrid v-section wheels), but half the depth of HED's flagship Jet 9. The weight is in the ballpark of traditional 32-spoke, box-section clinchers, which are the 'standard' wheels that many of us are on, but the aerodynamic properties of the Jet 4 are far superior.
HED has found that the Jet 4 slices 50-90 grams of aerodynamic drag off of a conventional wheelset. That's a minimum of a 25-40 second savings in a 40k time trial, or five to eight watts every second that you ride. Those savings are aerodynamic drag alone. There is also a reduction in the rolling resistance because of the Jet 4's 23mm wide C2 rims.
C2 stands for two Cs: Lower coefficient of rolling resistance (Crr) and better aerodynamics (Cda). Not without reason, the rims on the Jet 4 Wheelset are 23mm wide compared to the 19mm standard. This is to match widths with the tires that most use on their bikes -- 23mm. A 23mm rim paired with a 23mm tire changes the tire's footprint, resulting in more grip through straights and turns. This is because the tire has a straighter sidewall and deforms less at pressure. This design also produces a lower rolling resistance. In fact, when HED sent the wheels to Continental Tires for testing, the engineers shrugged their shoulders, figured there was no difference, but put them in the jig and ran the tests anyways. It turned out the 23mm width has 18% less rolling resistance. And because of the smoother tire shape, the transition air makes from the edge of the tread to the end of the rim is smoother, resulting in a more laminar air flow and less aerodynamic drag.
The C2 rim has a unidirectional carbon fiber fairing bonded to the rim. The fairing adds some strength to the structure, but it isn't where the spoke nipple actually rests. The spokes go through to the aluminum rim, and the spoke ports in the fairing are drilled, so, the spoke travels in a straight line from the hub to the rim. The Sapim hex-headed aluminum nipples are treated with a light thread-locking compound, and they're accessed from the outside of the rim. If you ever have a need to true the wheel, you can use a Park Tool SW-15 Y-wrench to do the job. The Jet 4 is laced Sapim CX-Ray stainless steel spokes, the fastest spokes in the business. The front wheel has 18 spokes in a radial pattern, and the rear has 24 spokes laced 2-cross to transmit all of your driving torque when you mash the pedals.
HED laced the rims to its FR Sonic hubs. they have a carbon fiber center section, and a minimalist shape that's as aero it gets. They run ABEC5 bearings on oversize aluminum axles, 12mm in front, 15mm in rear. The oversized axles are stiff, and with less deflection, the bearings run smoother and with less drag. One great aspect of the front hub is the wide spoke flange. Even with the low spoke count in the front wheel, the wider spoke angle creates the lateral stiffness you want for precise cornering.
The HED Jet 4 Clincher Wheelset is available in either Shimano/SRAM or Campagnolo freehub compatible versions. The wheels come with HED's titanium skewers, valve extenders, and rim strips. Please note that HED does not recommend this wheel for anyone exceeding 190lb.