Building a better bike rim for off-road punishment
Hard-core mountain bikers routinely pedal their way through a battery of rocks, roots, stumps and puddles, heaving heavy punishment on two lightweight aluminum rims. But a new generation of stronger, better performing off-road rims may be just down the designing path.
Two University of Wisconsin-Madison College of Engineering professors are working together with TREK Bicycle Company of Waterloo, one of the nation's top mountain bike manufacturers, on creating rims with novel properties. Materials science and engineering professor Frank J. Worzala and mechanical engineering professor Terry G. Richard are looking at materials outside the industry standard, such as titanium and stainless steel, to bolster the strength of rims. And unlike current rims, they are exploring a design innovation by creating rims with a solid cross-section, rather than the current hollow-box design. Such a design could lead to more precise rim alignment and eliminate the need to connect spokes to ferrules.
Other innovations include a laser welding technique that could produce stronger and cleaner welds. Current welds create an excess scar of aluminum that needs to be filed off. The welding will be done by Laser Machining Inc. of Somerset, Wis. A company called Thermal Spray Technologies of Sun Prairie, Wis., will apply plasma coatings to the surfaces of completed rims. The coating could provide better stopping power for bikes slathered in water and mud.
Mountain bikes are the fastest-growing segment of the bicycle market, with more than 4 million sold in 1994. Consumers are highly attuned to improvements in their performance. The company anticipates a prototype rim ready for production in about a