Sometimes we agonize over our wheel selection since they have the potential to make such a huge performance difference. In fact, wheels are probably the single most important component when it comes to parts selection for your bike. Luckily, the HED Jet 4 Clincher Wheels are a great compromise. It's light enough for hills, aero for flats, and stiff for sprinting.
Here, compromise isn't a backhanded compliment. All wheels are compromises. Aerodynamic qualities are important. Weight is important. Stiffness is important. Ultimately, you have to decide what's most important to you, and for the most part, the depth of the rim is the deciding factor. The deeper the wheel, the faster it is at higher speeds. But added depth translates into added weight. How much weight is too much?
The Jet 4 Clinchers are for people who want aero as well as light weight. The Jet 4 rims are 45mm deep, which is about double the depth of the HED Belgian series but half the depth of their Jet 9. The weight is in the ballpark of traditional 32-spoke box-section clinchers, the "standard" wheels that many train on, but their aerodynamic properties are far superior.
HED has found that the Jet 4 slices 50-90 grams of aerodynamic drag off a conventional wheelset. That's a minimum of a 25-40 second savings in a 40k time trial, or 5-8 watts every second you ride. Those “...the Jet 4 wheels combine slick aero shaping for fast riding with more comfort and more control...” 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). The rims on the Jet 4 Wheelset are 23mm wide when most rims are around 19mm, and it makes a big difference. The reason for the greater width is to match the tires that most folks use on their race bikes -- 23mm. A 23mm rim paired with a 23mm tire changes the tire's footprint. It grips better in a straight line, it grips better in turns because the tire has a straighter sidewall and deforms a bit less at a given pressure. A 23mm tire on a 23mm rim also has lower rolling resistance. HED sent the wheels to Continental Tires for testing. Conti's engineers shrugged their shoulders and figured there was no difference, but they put them in their testing jig and ran the tests anyways. As it turns out, Hed's C2 rim design offers 18% less rolling resistance than typical narrower rims. And because of the smoother transitions from tire tread, to sidewall, to rim, and finally to the trailing edge of the rim, the airflow is less disturbed. The result is a more laminar air flow and a lower aerodynamic drag. It might have seemed crazy at first blush, but the industry is following. Yes, it's a good idea to run 23mm or wider tires on any of HED's C2 wheels.
The C2 rim has a 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 sports Sapim CX-Ray stainless steel spokes, the fastest spokes in the biz. The front wheel sports 18 spokes in a radial pattern, and the rear has 24 spokes laced 2-cross so it transmits all of your driving torque when you mash the pedals.
While the rear hub may appear a bit pedestrian, the FR Sonic front hub is super cool and super light. It has a carbon fiber center section, and its minimalist shape is as aero as they get. 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 Wheels are available with either a Campagnolo or a Shimano/SRAM compatible freehub body. The wheels come with HED's steel-shafted alloy skewers, and valve extenders. HED does not recommend this wheel for people weighing over 190lbs.