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Product Comparison Test – Sunday, 8 September 2024 – Alkmaar, Netherlands
Marlene De Boer’s Transition from CADEX to TF1
In competitive triathlon, every marginal gain counts, and aerodynamic performance is often the key differentiator between victory and defeat. Marlene De Boer, the 2021 Ironman Overall Female Age Group (AG) Champion, claimed her title riding a Kú TF1. At the end of the 2022 season Marlene turned professional for 2023 and switched to a CADEX. She has now been racing the CADEX for a season and a half.
Despite recent race successes in Ironman Kalmar and Ironman 70.3 Poznan, Marlene recognised a performance deficit compared to her previous experience on the TF1. Earlier this year Marlene approached Kú Cycle to see what could be done. Now, she’s returning to her trusted TF1, seeking to reestablish her race performance.
Marlene joined the 9th September 2024 Kú Aerocamp at the Alkmaar Velodrome in the Netherlands with a specific objective: to evaluate and optimize her aerodynamic performance and equipment configuration after transitioning from the CADEX back to the TF1.
This blog outlines the testing and analysis conducted to compare her baseline aerodynamic drag (CdA) and power-saving potential between the CADEX and TF1 in different conditions,
Testing Approach
Marlene’s evaluation involved baseline testing of both the CADEX and TF1 in two key configurations: with and without race hydration. The primary goal of the testing was not to measure micro-effects due to equipment matching across the two bikes but to assess how Marlene’s performance would vary between the two bikes in their respective “as supplied” configurations.
The test protocols included removing the crank and powermeter from Marlene’s new TF1 for testing the CADEX and standardizing all other data recording equipment between the two bikes to ensure accurate comparisons. CdA was measured using the same Aerolab sensor.
Wheels: CADEX-branded four-spoke wheels.
Tire Size: 28mm tires.
Marlene had been fitted and tuned to this setup by Dirk Jan Liewes, a seasoned bike fitter responsible for both her CADEX and TF1 configurations.
Frame: Marlene switched from her original 2021/2022 TF1 S625 to the newer TF1 L620. The L620 frame is 18mm longer and 5mm lower than the S625.
Wheels: Kú spoked rims, with a 35mm rim on the front and an 80mm rim on the rear.
Tire Size: 25mm tires.
A critical factor in Marlene’s improved performance on the TF1 was her bike fit. Both her CADEX and TF1 fits were handled by the same experienced Kú fitter, Dirk Jan Liewes, ensuring consistency in her biomechanical setup.
However, while Marlene had been well-tuned by Dirk to the CADEX, the geometry of the bike did not allow for the same precise fit she had experienced on the TF1.
The longer and lower geometry of the TF1 L620 provided her with a better position that enhanced both her comfort and aerodynamics. A good fit not only minimizes drag but also maximizes power output and reduces fatigue over long distances.
This was a crucial element in her decision to switch back to the TF1, as she and Dirk were unable to achieve the same optimal positioning on the CADEX, ultimately impacting her performance potential.
The key aerodynamic parameter measured was Marlene’s drag coefficient (CdA), which directly influences how much power is required to maintain speed. Lower CdA values represent better aerodynamic efficiency.
The data below was achieved in a velodrome test with values compared at a constant velocity of 40kph or a normalised power of 250W
The Kú TF1 in race set up
demonstrates a 13% saving over
the Cadex in race set up
The Kú TF1 saved
Marlene 23 watts at
40kph over the Cadex
Over a full Ironman distance ridden
at 250W Marlene would save 11 minutes
on the TF1 compared to the CADEX
Without race hydration: Marlene’s baseline CdA averaged 0.222 across two measured runs.
With race hydration: Marlene’s race hydration setup on the CADEX involved a large bottle mounted to the seat tube, which negatively impacted her aerodynamics. The average CdA over two measured runs increased to 0.229 in this configuration.
Without race hydration: On the TF1, Marlene achieved a baseline CdA of 0.208.
Hand position adjustment: A small adjustment to Marlene’s hand position, achieved by narrowing the grips on the FastTT Aerobars of the TF1, resulted in a slightly lower CdA of 0.207.
With race hydration: Adding the Bento and BTA (between-the-arms) hydration setup on the TF1 further improved the aerodynamics, reducing the CdA to 0.199.
Aerodynamic Efficiency: The comparison between Marlene’s race setups on the CADEX and TF1 showed a significant aerodynamic improvement on the TF1. The difference in CdA between the CADEX (with hydration) and the TF1 (with hydration) was 13%. This improvement translates into a significant power saving and time gain over long-distance races.
Power Savings: At an average speed of 40 km/h over an Ironman distance, the 13% difference in CdA corresponds to a 23-watt power saving for Marlene on the TF1 compared to the CADEX.
Time Gains: This power saving would result in a time reduction of 10 minutes and 48 seconds over a full Ironman distance when riding at a consistent power output of 250 watts.
Marlene’s transition back to the TF1 from the CADEX provided her with substantial aerodynamic benefits, mainly due to the optimized setup of the TF1, including a more aerodynamic position and improved race hydration integration.
These benefits not only enhance her power efficiency but also offer considerable time savings over long-distance events, making the TF1 a superior choice for her future races.
The meticulous testing and analysis conducted for all athletes attending Kú Aerocamps underlines the importance of tailored bike fitting, equipment configuration, and continuous refinement of race setups for achieving peak performance in competitive cycling.
The meticulous testing and analysis conducted for all athletes attending Kú Aerocamps underlines the importance of tailored bike fitting, equipment configuration, and continuous refinement of race setups for achieving peak performance in competitive cycling.
For Sales Enquiries:
Ed Grace
ed@ku-cycle.com
+44 7894 307395
Media Contact Kú Cycle:
Alex Bok
alex@ku-cycle.com
+31 (0) 683 033 920
About Kú Cycle
A Dutch based company with a mission to design bikes and performance solutions that will change the sport forever – the perfect fit between body and machine. We believe a rider’s position should be established independent of the bike and will therefore reposition bike fitting services from a post-purchase service to a pre-purchase service. A new production process (built-to-order) and a completely different sales model are introduced with a single objective: athlete performance delivered!
Transistorstraat 151
1322 CN Almere
The Netherlands
KvK-nummer: 74978454
VAT: NL860095629B01
Email: info@ku-cycle.com
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