MINNEAPOLIS — Polyethylene spokes from Berd LLC can shave up to 200 grams from a wheel while offering an improved fatigue life compared to metal spokes. The company’s technology has caught the eye of weight weenies and the National Science Foundation, which awarded Berd a $225,000 grant last year.
What caught NSF’s eye was the company’s patented technology for grafting braided hollow polyethylene to a threaded stainless steel end that attaches to a standard nipple at the rim.
“Creating a hybrid of polymer and metal is very difficult. Polymers are difficult to bond to,” said Charlie Spanjers, who founded Berd Spokes with Kyle Olson and Brad Guertin.
While Berd bonds the polyethylene to the threaded end, what really holds them together is the way the braid works like a Chinese finger trap, Spanjers said.
“The braid under tension provides a majority of the hold power,” he said.
Spanjers recognizes that there have been various attempts at metal spoke substitutes in recent years, including spokes made of carbon, polymer and other materials. But none remain on the market apart from those used as a part of integrated wheel systems. Berd’s
PolyLight spokes work with standard rims and with hubs designed for straight-pull or J-bend metal spokes.
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