Sam is a passionate triathlon coach with years of experience helping athletes unlock their full potential. A seasoned competitor, he raced at Kona, represented GB at World and European Championships, completed over 10 Ironmans (including a sub-10-hour finish), and tackled epic challenges like cycling non-stop from Glasgow to Land's End.
Sam’s primary objective was to evaluate the aerodynamic performance of three different skin & trisuits he brought to the session. Among them were his training skinsuit, his current race skinsuit, and a brand-new skinsuit that he unboxed during the session. Sam was particularly keen to analyse the data behind the new skinsuit, as he planned to use it as his future race suit.
Sam’s testing plan centered on two key objectives: determining which skinsuit was the most aerodynamic for him and ensuring it provided sufficient comfort for long-distance racing.
The testing was conducted over multiple 4km sessions, consisting of 2km out-and-back runs on a straight road. To ensure accurate results, we had two testing variables being the skinsuit & trisuit being worn. The second variable was Sam’s position, we broke the tunnel up into 4 test sections, each test section was 1km in length. The four positions were: Neutral, heads down (tucked), helmet pointing upwards, relaxed position.
Figure 1: shows the aerodynamic drag (CdA) of three skinsuits: R1 (training), R2 (current race), and R3 (potential new race)—and the corresponding watts saved or lost:
Key takeaway: R2 is the most aerodynamic option for Sam, providing measurable time savings. R3, despite being a potential upgrade, increases aerodynamic drag, resulting in significant time losses.
Figure 2: Saddle Position and Power Balance (R2)
Figure 2: explores the rider's position on the saddle (mm from the mount) while using the current race skinsuit (R2).
Key observation: Saddle position changes with each position (4 positions), but remains relatively consistent when he is in each position, with only minor fluctuations. This consistent positioning helps minimise drag and maintain aerodynamic efficiency, likely contributing to R2's superior CdA performance in Figure 1.
Implication: Stability on the saddle is a key factor in achieving and maintaining aerodynamic optimisation.
Figure 3: highlights the rider's saddle movement while wearing the new potential race skinsuit (R3).
Key observation: Compared to R2, R3 shows far greater shuffles in saddle position, with noticeable instability. This movement likely indicates reduced comfort or a poor fit, forcing the rider to adjust frequently.
Additionally, Sam mentioned that his new skinsuit felt more slippery on the saddle during this ride. Upon inspection, we found that the material of the skinsuit in contact with the saddle has a lower coefficient of friction. This characteristic appears to be contributing to the increased shuffling, as it makes it harder for Sam to maintain a stable position, potentially compounding the discomfort.
Correlation: The increased movement not only disrupts aerodynamics but may also contribute to the higher CdA seen for R3 in Graph 2, explaining its poorer performance.
A further step would be to evaluate alternate saddles with grippier covers to see if the shuffling could be solved.
