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Tunnel Tested With Cameron Dye

  • By Aaron Hersh
  • Published Apr 16, 2012
  • Updated Dec 17, 2012 at 3:57 PM UTC
Diagram by Bridget Durkin.


With Dye’s bar height set, the team started looking at the rotational orientation of the aerobar and his forearms. The aerobar extensions on his Pro Missile bar can’t rotate upwards without also spinning the basebar, so Barber instructed Dye to ball his hands into fists and rest them on top of his S-bend extensions to angle his forearms upward. Lifting the hands high above the elbows allowed the forearms to block air from flowing between his upper arms and getting caught against his torso. Many riders including Tour de France road racers and forward-thinking triathlete TJ Tollakson have found this strategy reduces aero drag, and DeBoom held high hopes it would also work for Dye. Barber crouched down in Dye’s line of sight and used his own arms to simulate the position, telling Dye, “We’re going to try and split the air with your arms so it doesn’t hit your torso and your pelvis. Sometimes it works, sometimes it doesn’t.” Steinmetz reminded Dye to keep his hands high to really seal off his torso and pulled Dye’s elbow cups in tighter, to further help direct air around the side of Dye’s body rather than up the gut.

Ryle started the fan again and data quickly started flowing in. They found a way to make Dye faster.

Thinking in grams of drag, the unit measured by the balance, is conceptually foreign to most, so Barber used an equation to convert the grams saved to watts. This new hands-up position saved roughly 16 watts. To find even more free speed, the advisers coached Dye in another technique frequently used by time trialists: turtling. In almost all positions, even aggressive ones, the head pokes above the back and collides with otherwise smooth airflow, but if a rider tucks his head down between the shoulders, which some call it turtling, it can reduce drag. However, turtling can also can strain the back, hamstrings and shoulders. Dye practiced this position before the next run. Steinmetz told him, “Try to bring your shoulders to your ears. Shrug.” When the fan was up and running again, Dye’s head was still sticking up a little too high. Ryle got on the microphone and instructed him to drop his head. Barber liked what he saw and whispered to himself, “Oh come on, hold that position.” The numbers registering on the small screen in front of the technician raised the excitement level in the control room. Shrugging his shoulders turns a 16-watt savings into 28 watts—a real game-changing number. “Drastic,” DeBoom said. “He should be able to hold that for 40k, easy.”

Dye wasn’t so sure. “Narrow I feel is doable. Raising the hands without lifting the back, I don’t know,” he said. Pointing the hands up also lowers the elbows slightly if they hang off the back of the pads, as was the case for Dye. Simply lowering the bars didn’t yield any aerodynamic improvements but did threaten his biomechanical function; lifting his hands had a similar effect on his ability to pedal the bike but did reduce drag. He must acclimate to this position to reap benefits on race day.

Dye’s head protruded above his back in every trial so far except for the turtle tuck position. His Rudy Project Wingspan helmet has a short tail that doesn’t close the space between his head and back. Rudy is one of Dye’s biggest supporters, but the advisers were curious to see if another helmet is faster. Dye hesitantly tried another lid for a repeat of the “hands up” position.

The new helmet eliminated the opening behind Dye’s head and turned his back into a textbook aero profile, but when the data started showing up, everyone was surprised. Dye was substantially more aerodynamic wearing the Rudy Project Wingspan. Somehow, the position with an unsightly space behind his neck was faster. Barber summed it up: “The one thing about coming here, you can think that something is fast, but until you test it, you have no idea.”

After nailing Dye’s helmet selection, attention turned back to his hand position. The group decided the basebar could be rotated upward slightly without presenting a giant wind-blocking surface. Steinmetz spun the bar upward to elevate the tip of the aerobar extensions. The final segment of Dye’s S-bend aerobar extensions were angled slightly upward, but they didn’t position his hands as high as ski-tip style extensions. To simulate the other position option, Barber once again instructed the test subject to ball his hands into fists and rest them on top of the shifters, just like his original run before rotating his basebar. Coupled with the upturned bar, this setup positioned his hands several centimeters higher than his previous test runs, relative to his shoulders. Before closing the door and testing this position, DeBoom instructed Dye to switch positions part way through the trial. Dye was to keep his head in a comfortable, neutral position for the first portion, then he would be given the cue over the loud speaker to drop his head and shrug his shoulders.

The first data that came in—hands on top of the aerobar extensions with the entire bar rotated upward—showed slightly more drag than the same position with the bar flat. Then Dye dropped his shoulders. “That’s a hell of a number,” exclaimed Ryle. “If he can rid that—wow. It’s unbelievable when he gets his head position right.”

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FILED UNDER: Gear & Tech / Pro Bikes / Triathlete Buyer's Guide TAGS: / / /

Aaron Hersh

Aaron Hersh

Aaron Hersh is the Senior Tech Editor of Triathlete magazine. To submit a question, write Aaron at Ahersh@competitorgroup.com.

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