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Not so long ago, “professional” bike fitting was akin to “alternative medicine.” Weights attached to strings were the tools of the trade, measurements were done by eyeball, methods were unabashedly unscientific. But then in the mid-2000s, technology began to slowly creep into the equation in the form of 2D and then 3D motion-capture analysis. Dedicated bike fitting companies such as Retül and Guru sprang to life. Nowadays any bike shop worth its salt offers some form of professional bike fitting services.
“A decade ago we saw this explosion of technology come into the space,” said Mat Steinmetz, a longtime professional bike fitter and founder of 51 Speedshop, a manufacturer of high-end time trial bike components. “Now it’s gotten to the point where it’s basically an expected service.”
So what is new in the world of bike fitting? The short answer, especially if you’re on a WorldTour team, is qualified performance testing and validation. Instead of simply addressing the issue of comfort on the bike, bike fit is being used to gain speed and efficiency.
“We’ve been doing motion capture and looking at joint angles for a while now,” said Todd Carver, the Human Performance Manager for Specialized, and founder of Retül. “Now we are adding in a performance testing element, looking at both the metabolic and aerodynamic effects of various positions on the bike. It’s basically become three bike fits in one.”
For example, this off-season Carver will work with riders from Deceuninck-Quick-Step. He’ll start with a traditional Retül motion-capture fit to dial in the basics and assure comfort. “Then we’ll move over to what we call the Move Bike and take them through a variety of stack heights and other variables in real time while pedaling,” Carver said. “At the same time we’ll test the rider metabolically through the recording of oxygen consumption at various positions and then essentially convert that to a metric where we can see exactly how efficient in watts produced the rider is in a given position.”
Finally, Carver will take riders onto the track to analyze the aerodynamic impact of that ideal position. “What we may find is that if we take the rider too low, they start to work harder and are penalized by, say, 8 watts,” he said. “But then you might go on to the velodrome and see that the position is 16 watts better aerodynamically, so there’s a net gain.”
The idea is to find that perfect balance between a position that a rider can comfortably maintain for a six-hour Tour de France stage, while also remaining physiologically and aerodynamically efficient enough to do their job.
Bike fit frequency has changed too, said Chris Jacobson, product line manager for PRO Bike Gear and Bikefitting.com, which are both owned by Shimano. “There’s a lot of misguided knowledge about when you should get a bike fit,” Jacobson said. “It’s not just when you get a new bike, which has been the common conception for a long time.”
Just like an annual physical, most riders benefit from yearly bike position check-ups, assessing things such as changes in flexibility. But few riders are willing to shell out up to $300 for the procedure, assuming that one fit is all you need. Now, with the onslaught of component variability such as wider bars, short-nosed saddles, and shorter stems and cranks, the need for those bike fit check-ups has further increased.
“Anytime something changes, whether it’s wider bars on a gravel bike or a new set of shoes, it really makes sense to get an understanding of the impact of that change,” said Jacobson, who does fits using a 3D Pedaling Analyzer, which has the ability to adjust crank arm length and then measure the force application in real time. “The reality is that you don’t have lifetime numbers. Your interface with the bike changes over time, whether its new components or changes in physical ability, flexibility, or age. Getting fit can assure that you get into a position that’s functional and efficient.”
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