Ric Hjertberg models his new carbon babies © Josh Liberles
by Josh Liberles
I had the chance to test out Mad Fiber’s tubular creations a few weeks ago at a shop demo in Portland, and got to follow up with the creators here at Interbike today. One look reveals that the company’s recently-released wheel offerings aren’t just another addition to the carbon hoop market. First off, the spokes are thin carbon blades, and they’re bonded to both the rim and the carbon shell that surrounds the hubs. In essence, each wheel is one structural unit, designed to take full advantage of the properties and possibilities of carbon fiber. And each of the spokes (12 front, 16 rear) is less than 1cm wide.
Ric Hjertberg took advantage of his Seattle-based company’s proximity to Boeing’s headquarters and enlisted the design help of Max Kismarton, who has designed several cutting-edge military vehicles. Together, they’ve developed a completely new way to build and tension a rim, according to Hjertberg.
“With wire-spoked wheels, the reason for the high level of tension is not for ride quality or performance; it gets the fatigue life to go way up,” said Hjertberg. “With our carbon process, we can fine-tune tension to be exactly where we want it. We’ve found the best performance and vibration absorption to happen at about half that tension, and we aren’t sacrificing durability.”
The rim and spoke: a complex layup bonded together into simple shapes © Josh Liberles
Unlike bladder molding, an expensive process which relies on costly tools and is prevalent throughout the bike industry, Mad Fiber relies on a high-pressure autoclave process, which Hjertberg likens to Formula 1 and aerospace applications. As a result, the five-ply carbon fiber laminate relies on a complex layup bonded together into simple shapes. The rims, spokes and hub shell are bonded together and are all structurally integrated.
While I’d never label a $2,600 wheelset as “reasonable,” they’re priced competitively with some of the carbon fiber industry leaders and, considering the rim depths of 60mm front / 66mm rear, they’re among the lightest models out there at 1085 grams. Add that to the fact that there’s a four-year warranty, a crash replacement policy and no rider weight limit, and it’s clear that these guys are confident in their work.
Because of the wheel’s interconnectedness, it’s hard to break out rim weights from the rest of the wheel – but Hjertberg estimates the rotational weight to be in the 200-gram ballpark. While the ’cross-specific designs will be a few grams heavier due to lashings added to give the spokes more lateral stability in case of crashes or objects becoming lodged while riding off-road, the ride quality is expected to be virtually identical.
Carbon-spoked predecessors like the Spinergy Rev-X are now illegal because they have fewer than 12 spokes. The Mad Fibers start with 12 spokes, and according to Hjertberg will flex in a crash rather than acting like a cleaver on skin. For you Elites out there, the wheels head to the UCI test lab in October for certification so that you’ll be able to use them in UCI events.
OK, so what about the ride? During my demo a few weeks back, I only spent about 20 minutes flying around industrial Northeast Portland, so it’s tough to give a full-fledged report. But, on first blush, I can say they accelerated like crazy, which you’d expect at that weight, and they were stiff and super-responsive. And, yes, here it comes, perhaps the most overused phrase in bikes – they’re “vertically compliant.” I intentionally drilled it every time I passed over a particularly bumpy railroad track section, and while I certainly felt the terrain beneath me, there was some nice vibration absorption.
Look for a more full-fledged product test and review from us soon. Also, keep your eyes out for a clincher wheel from Mad Fiber within the next year.
Profile: 60mm front / 60mm rear, currently tubular only
Weight: 1085g, about 10g more for ’cross wheelset. Without the hub guts, entire wheels are 380g front, 430g rear
Spokes: 12 front / 16 rear
Hubs: White Industry
MSRP: $2,600, includes lightweight skewers, cork brake pads, valve extenders and wheel bags
More info: Madfiber.com