Composite gives exercise bike competitive edgeComposite gives exercise bike competitive edge

Irvine, CA--Exercise bikes used in health clubs rack up about 10 hours of use per day. Therefore, to be competitive in today's hot exercise-equipment marketplace, Tony Koselka, engineering manager at Tectrix Fitness Equipment, must design his firm's bikes to last from five to seven years. Helping to give Koselka a jump on the competition is a newly designed thermoplastic composite pillow block, the structure that supports the bike's drive shaft. The design rewarded Koselka with a lighter, less costly component than the steel version it replaced.

The material selected, Verton(reg) RF, a long-glass-fiber-reinforced nylon 6/6 structural composite, is formulated by LNP Engineering Plastics (Exton, PA). And in making the switch from steel to the composite, Tectrix realized an immediate cost savings. Steve Agnoff, president of the Efson Div. of power-transmission component maker Fenner Drives (Wilmington, NC), the firm that produces the pillow blocks for Tectrix, explains why.

"By turning to the composite, we could use one design for two interchangeable parts, eliminating the need for two separate steel parts," says Agnoff. "The less parts to fabricate, the greater the cost savings for our customers. Moreover, the composite gives the part the high-impact, fatigue resistance, wear properties, and the structural integrity required for the application."

"When compared to conventional short-fiber-reinforced thermoplastics, Verton structural composites have enhanced mechanical properties, while remaining lightweight," adds Dick Sabo, Verton product market manager. As an added bonus, this combination of properties cut the weight of the pillow block from eight to one and one-half lbs.

"We did lifetime testing to make sure the material didn't creep over time," Koselka notes. "We also did some strength and testing. The composite gave us the performance we needed."