The Blackwell Research 50mm Carbon Clincher begs the question: Is a carbon-rimmed clincher better than an aluminum clincher?

The two biggest differences between carbon and aluminum rims are weight and braking performance.

Weight: Carbon clincher rims are lighter, but only slightly. Tubular carbon rims are so much lighter than aluminum clinchers because they are made with less material. But a carbon clincher is just as massive as an aluminum clincher. As a result, the weight savings is modest.

Braking: The BR 50mm Carbon Clincher has an embossed braking surface composed of “’lava dust’ and carbon fiber”. The braking surface is raised off the rim, presumably, because carbon fiber holds heat longer than aluminum. Extreme braking can generate a surprising amount of heat, which warms the tire. If the rim gets hot enough, tire pressure and can climb high enough to cause a very dangerous tube blow-out. Increasing the volume and surface area of the braking surface should decrease the chance of this happening.

Although Blackwell obviously put a lot of effort into keeping the rim cool, the Carbon Clincher simply doesn’t brake well. These wheels require specific brake shoes and pads, which are included with the wheels. The shoes were extraordinarily difficult for me to set up correctly, and I’m a bike mechanic by trade.

At first, the grip between the rim and pad was mediocre, but acceptable. After only a couple hundred miles, a slick black residue began to build on the brake pads. This residue further reduced stopping power and created a heinous howl while braking, which earned me countless dirty looks from other cyclists.

Aerodynamics: Without designing a revolutionary aerodynamic rim shape, Blackwell Research can only do as well as third best. The toroidal (widest at the middle, kind of like a football) rim shape has shown over and over to be the grand champion of aero rim designs. But here’s the catch: Zipp and HED share the toroidal rim patent, so they are the only companies that can use this very valuable shape. Until someone comes out with a new rim shape, all other wheel manufacturers will be competing for the title of third most aero wheel per rim depth. I don’t claim to know the specific aerodynamic characteristics of this wheel, but I highly doubt that they are superior to the offerings from Zipp and HED over wind angles from zero to 20 degrees.

VERDICT
Although the Carbon Clincher 50mms are very stiff and precise, the braking performance drastically diminishes ride quality. At 1550g, they are not a feather weight at the $1,740 price tag and 50mm depth. The stiff construction makes the 50s fun to rip around corners or winding up for a sprint, but they are not the best option for a tri race wheel (read: most aero) because they do not have the toroidal rim.

The Carbon Clincher 50s would make a great high-end everyday wheel, if you can tolerate the braking performance. All things considered, the best attribute of the Carbon Clincher 50s is the fashionable carbon rim on a clincher for less than $2K.

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Aaron Hersh is the Technical Liaison at Colorado Multisport in Boulder, Colorado. He has been competing in endurance sports for the last seven years. Hersh has a B.A. in Integrative Physiology from the University of Colorado, focusing on biomechanics.

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