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If designing for simplicity was the mantra steering the R&D efforts around the Trek Lime, designing for carbon was the guiding principal behind the new Madone high-performance road bike, which Trek rolled off the line in May.
The Madone, first introduced in 2001, gained celebrity as one of the first to exploit the lighter carbon fiber materials and, more notably, as the bike icon Lance Armstrong rode in several of his Tour de France victories. Yet as more bike companies and off-shore manufacturers gained experience with carbon fiber composites and with Lance’s retirement from professional bike racing last year [CK], Trek knew it needed to pump new life into the Madone, which had basically carried the same design since its inception.
“Now that everyone was able to create the features of the Madone, we knew we had to step up and do something totally different,” says Doug Cusack, Trek’s senior research and design engineer. “We needed something totally new to leapfrog the competition.”
To get that novel something, Trek wiped its development slate clean. “Trek developed the first carbon bike in 1991 and a lot of things got carried over,” Cusack says. “Every year we’d do a new design, the old design came with it. This was the first time we started with a clean sheet of paper.”
The two-year development effort started with a handful of people and ideas and eventually blossomed into Trek’s largest initiative to date, engaging over 100 engineers, manufacturing personnel, designers and marketing professionals. Most of the innovation came from being free to design for the unique properties of the carbon fiber materials, not being stuck with limitations associated with traditional materials like aluminum, Cusack says.
Consider the new Madone’s drive train. Traditional bike frames are restricted by the industry-standard, 68-mm bottom bracket shell width, but the new Madone was able to leverage Net Molding carbon technology with a new socket approach to create a larger, 90-mm-wide frame design. This allowed the new bike to maintain the necessary “stiffness” for performance and bike handling while shaving 40 grams off its weight compared with other models. Weight reduction, which leads to higher performance, was accomplished in other ways. A fresh fork design eliminates the need for larger (i.e., heavier) forks used on older Madone models, and an integrated seat mast also serves to cut out unnecessary materials.
“With this Madone, we were able to design around carbon materials whereas a lot of time, with our older bikes, the design was driven by the old steel frames,” Cusack says.
SolidWorks 3D CAD tools and its integrated COSMOS simulation tool, along with the ANSYS finite element analysis (FEA) software, played a key role in keeping the designs grounded in reality. According to Cusack, the team spent hundreds of hours with FEA for this bike, much more than any other bike development effort. “Because you can easily change the shape of a tube in carbon fiber, there was a lot of 'what-if' you made something rounder or narrower or took a different ply orientation with the carbon fiber materials,” he says.
Trek also built two versions of the bike, a production version and a physical prototype — which is something it doesn’t always do. Trek engineers, including Cusack, spent six weeks in California doing the road testing on the prototype, and Armstrong himself did some test rides at the end. “Because this is the first time we had a chance to design for materials, we played with different shapes,” Cusack says. “But we needed to see how what we got in the FEA testing would test out in real-life riding.”