Still the one.
In terms of race pedigree, you'd be hard pressed to find a rim that enjoys more time on the podiums of Europe than Campagnolo's iconic Bora rims. With the Bora One 50 Wheelset, Campagnolo brings this proven rim design into the self-sponsored racer's range by mating it to Ultra Smooth Bearing (USB) hubs instead of the Bora Ultra's Ceramic Ultimate Level Technology (CULT) hubs. While this does result in a pair of differences in the hubs, the Bora One 50 Wheelset is still the one that's reliable and fast enough that certain members of Europcar opted to ride it during a race as trying as Roubaix.
The first difference between the hubs is that the USB hub body is alloy instead of CULT's carbon, for a slight sacrifice in weight (50 grams, claimed) and stiffness. Second, USB includes the inimitable smoothness of ceramic bearings but without the benefit of CULT's Cronitect races. Despite this concession, the USB system is still a claimed 50% smoother than steel, which is the industry standard.
The rims laced to these hubs benefit from the new width of 24.2 millimeters, up from the previous 20 millimeters. This wider rim is general across the Bora line, and it brings improvements in handling and cornering, lower rolling resistance, and a smoother ride. It also nets better lateral stiffness and — in a counter-intuitive twist — actually improves aerodynamics. The width also saves weight by letting Campagnolo build a more structurally sound rim with less material, and it means you can mount bigger tires, up to 27 millimeters, for a tubular ride that's more plush and durable than ever.
Like its Ultra counterpart, the Bora One 50 also features Campy's new 3Diamant braking surface, which addresses some of the key braking issues we've had with carbon rims in the past. Campagnolo literally uses diamonds to hone the brake track to near perfection, removing a microscopic layer of imperfections and resin so that the pads connect straight to a strip of slightly textured carbon. This reduces the time it takes for the brake pads to grab the rim and it all but eliminates the usual breaking-in period for carbon brake strips, increasing stopping power by 40% in wet conditions and 20% when it's dry. It also removes any surface imperfections in the wheel for a pulse-free ride.
Campagnolo finishes off the Bora One 50s with a few more thoughtful details. The oversized rear flange nets additional stiffness for power transfer that takes advantage of the rims' aerodynamic profile and smooth bearings. The included quick releases have also been redesigned with an eye toward weightloss and aerodynamics. Returning features include the signature G3 spoke pattern, which absorbs road noise and improves power transfer, and rim balancing that offsets the nominal imbalance caused by the valve stem hole and associated hardware. Campy constructs and lays-up all of the carbon for the Boras in Vicenza, and every piece is X-rayed to scan for imperfections.
This iteration of the Campagnolo Bora One 50 Wheelset is compatible with tubular tires only, though Campagnolo has announced a clincher version due out in spring, 2015.