The new triathlon bike from Felt is integrated, adjustable and very triathlon-specific.
Picking the right triathlon bike has become a balancing act. It used to be that some tri bikes were poor and others were good—choosing from the limited number of good ones was easier. Now there are many great bikes with different strengths and weaknesses. Some bikes are shaped for really demanding positions and others are geared for more upright riding styles; many tri bikes are mechanically easy to deal with, but less integrated (and in some cases not quite as aerodynamic) while others conceal many parts and can create logistical headaches. Felt’s IA, seemingly ready to join the group of great tri bikes, is integrated but is not a mechanic’s nightmare, it is adjustable and is shaped to match many different fits.
Felt abandoned the restrictions that come with conforming to cycling’s governing body, the UCI, and made this bike with giant, almost ridiculously deep tubes. And they didn’t just extend the length of a pre-existing tube. They went through the processes of testing and refining aerodynamic design that has become standard when creating a tri bike with aspirations of earn a spot among the fastest.
The design processes started in CFD, the so-called “virtual wind tunnel,” then Felt created physical models of many different tube shapes and frame pieces and tested them at the San Diego Low Speed Wind Tunnel. They pieced together various options and compared how the shapes did when paired together and with spinning wheels to determine which designs perform best when put into a complete bike system. This entire process has become standard when top-level bike makers create an aero frame and Felt followed the procedure that has resulted in many of the most aerodynamic bikes in the world.
In addition to throwing out the UCI regulations, Felt ignored one other convention of time trial bike design: The frame was created for riders averaging speeds typically held by amateur triathletes, not the incredible velocities pro time trialists produce. “We are getting to a point where we can’t have a bike perform [at the highest level] in every possible condition,” says Felt aerodynamicist Anton Petrov. For the IA, Petrov and Felt’s R and D team designed around conditions experienced by triathletes. Riding slower means that wind angle is effectively broader—further from head-on—and this set of conditions demands a certain set of design characteristics.
Felt experimented with removing the seat stays from the bike to reduce aerodynamic drag. While these models created measurably less resistance, they were insufficiently stiff for normal riding without modifying the frame in other ways that came with different negative consequences. Instead of doing away with these tubes, Felt’s engineering team elected to lower the seat stays far down the seat tube. Petrov says this design creates a little more drag than versions without this tube, but less than iterations with seat stays that attach by the top tube.