Nylon lost-core bike wheel improves on tradition

Designed for the "dirt-jumping, street-thrashing" kids market, the Thug wheel represents a leap in thermoplastic performance for a bicycle wheel. Designed and manufactured by Innovations and Composites Inc. in Vista, CA, the wheel was nine years in the making and reportedly outperforms and outlasts traditional aluminum and alloy designs.

Innovations and Composites president Kirk Jones says the one-piece thermoplastic urban gear (Thug) wheel is molded via the lost-core process and weighs a full pound less than comparable aluminum designs. The resin, AlliedSignal's Ultratough glass-filled nylon, helps the wheel hold up to impacts that cripple traditional designs.

To prove the strength, Jones, at the Interbike show in Las Vegas in September, repeatedly dropped a 45-lb lead and steel fixture from 4 ft high onto an upright, tireless Thug. It held up. He conducted the same test on a competing aluminum wheel. It failed. "The hollow geometry gives us a super stiff, impact modified wheel," Jones says. "The load is carried throughout the entire part." The geometry and the reinforced nylon also keep the wheel stiff where other plastic wheels flex or deform, allowing the tire to pop off, he says.

Jones says his company, building wheels since 1993, assessed other manufacturing processes, but none could provide the consistency of geometry and hollowness required. Gas assist, he says, produced inconsistent wall thicknesses. He contemplated molding the wheel in halves and welding them together, but "the biggest stress is along the center of the wheel rim. There's no way in the world we could weld there."

An integrated work cell runs two shifts daily producing the 20-inch wheels. Jones consistently achieves pressures of more than 20,000 psi over the metal core. A six-axis ABB robot automates the process.

At $200 a pair, the wheels aren't cheap but are comparable to high-end aluminum units. The next target market is the new generation of mountain bikes. The challenge, says Jones, is disk brakes, which grab the wheel at the hub. This stresses the wheel in new places and introduces a host of different design and manufacturing concerns. Jones says the Thug is an evolutionary result of five years of R&D in producing the company's full line of wheels. "We're talking years and millions of dollars in development to where we feel like we have a handle on this beast," says Jones.