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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.
Like pretty much every other tri bike maker, Felt’s new design is built around an age grouper-appropriate geometry scheme. True to their claim that the IA is created around the needs of amateur triathletes, the frame has a relatively short horizontal reach distance to the aerobar compared to the vertical stack height of the front end. Translated, its fit dimensions aren’t overly demanding. It’s dramatically different from Felt’s ProTour-oriented DA time trial bike. The IA’s stack and reach dimensions nearly mirror the Trek Speed Concept and Cervélo P5. In contrast to those two tri bikes, Felt’s smallest size uses 700c wheels instead of smaller 650c versions often spec’d for very little bikes.
The stack and reach dimensions for the five frame sizes are listed below in millimeters.
The IA uses a proprietary integrated system to mount the aerobar to the bike, and they created a cadre of pieces to allow the bike to accommodate a broad range of positions and fine tune fit down to the millimeter. The stem blends smoothly with the frame and fairing clamps to the steerer tube on one end, and the basebar bolts to the other. The stem can be spaced several centimeters above the head tube, just like a standard stem. The only difference is that this integrated stem can’t be angled upward to add more stack height to be basebar position. In addition to the ability to raise the basebar, the elbow pads and extensions can be spaced upward in unison. This method relaxes fit for the aero position while preserving a more aggressive body position when gripping the brake levers to climb and corner. The extensions and elbow pad location can be moved back and forth over a wide range. All these elements add up to create a geometry scheme that can be tailored to a huge span of triathlon-specific aero fits from very aggressive to conservative.
When Felt showed the IA to the media, it included an elaborate integrated storage and hydration system that has since been scrapped. The display bike had a single bottle mount on the seat tube. As of now, these bolts are the only storage option built into the bike.
The brake—both front and rear are mechanically identical—has a narrow shape and it mounts to the frame without any pieces extending away from the frame. A standard external caliper is certainly easier to adjust, but Felt’s aero version seems to have eliminated some shortcomings of other integrated aero brakes. It is quite similar to the brake on the Trek Speed Concept 9 Series, but with a few refinements that make it easier to adjust.
Felt’s brake is fairly easy to work on despite being fully integrated into the frame. It can be tuned to fit narrow rims or broad aero wheels without moving spacers or filing brake pads. A cover attached by two screws shields the brake. Remove it and the cable is exposed. A piece that attaches to the cable slides on a track that keeps it fixed in place, allowing the cable to be easily pinched using a single Allen wrench instead of requiring another wrench to hold the pinch piece. The pads can be toed in any direction and adjusted horizontally.
Either mechanical or electronic drivetrains can be set on the same frame.
Felt designed a unique seatpost retention system that eliminates the risk of crushing the seatpost. As an added benefit, a cosmetic piece of the system marks saddle height when the post is removed.
Felt is renowned for trickling top level technology into more affordable bikes, but bargain seekers will have to wait for this bike. The IA is being offered as a frameset or complete build with Shimano Dura-Ace Di2 and Mavic CXR80 aero wheels in 2014. These are both seriously high-end options. Cheaper versions are likely to follow in the future.
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