During Stage 4 of the 2025 Critérium du Dauphiné, Iván Romeo—current U23 time trial world champion—caught attention not just for his speed, but for his technique while descending at nearly 80 km/h on a time trial (TT) bike. His approach has sparked renewed conversation in the cycling world about the best aerodynamic positions for descending during high-stakes time trials.
Romeo, known for his precision and aerodynamic expertise, maintained an aggressive aero tuck throughout a steep and straight descent section, highlighting the fine line elite riders walk between maximum speed and control. While the descent wasn’t overly technical, the speeds involved required serious focus and confidence.
Aerodynamic Position vs. Control: Finding the Balance
On TT bikes, positioning is everything. Romeo’s crouched, streamlined form reduced his frontal drag significantly, helping him maintain high speed without extra pedaling force. He kept his elbows locked into the aero bars, torso low, and head tucked—a classic aerodynamic stance. However, on a descent, riders must adjust slightly to ensure stability and maneuverability. Romeo managed this well, showing excellent bike-handling skills even at near-terrifying speeds.
While this technique is efficient on long, straight descents, it can become dangerous on twistier or more technical sections. Unlike road bikes, TT bikes are more rigid and less agile, making fast downhill cornering riskier. Some riders or commentators might argue that in such cases, a traditional road bike or a hybrid strategy (like switching bikes mid-race) could offer better safety and control.
Romeo’s Advantage as a U23 TT World Champion
Romeo’s ability to maintain composure and posture while flying downhill at 80 km/h reflects his time-trialling pedigree. Having mastered pacing and aerodynamics during his world title run in Zurich, he’s comfortable pushing the limits—especially on descending terrain. He likely maps out his effort to push on climbs and flats and use descents to recover while still maintaining momentum.
The time trial stage of the Dauphiné favored specialists like him, with smooth descents that allowed riders to stay low and fast. Romeo appeared to remain in his aero position for most of the drop, leveraging both bike design and body mechanics to carry speed without constant pedaling.
Online Debate: Is the TT Bike Always Best for Descents?
Cycling forums and fans have weighed in, reigniting the debate over using TT bikes versus road bikes for hilly or mixed-terrain time trials. TT bikes clearly win on flats and straight drops, but they lose some appeal in tight, winding downhill corners. Some fans even wondered whether teams should reintroduce bike swaps for stages with mixed elevation, though that adds time and complexity.
Others pointed to Romeo’s apparent aero chest fairing or padding under his skinsuit, a technique that smooths airflow and further reduces drag. Subtle innovations like this are increasingly common in time trials, giving small yet meaningful time advantages.
Gearing and Confidence Also Play Key Roles
At such high speeds, gear ratios matter too. Romeo and others likely used oversized chainrings—possibly up to 60 teeth—to ensure they could maintain power and cadence even while pushing big gears down long descents. But physical courage and mental readiness are just as important. Descending at 80 km/h on a TT bike demands full trust in equipment, terrain knowledge, and instinct.
Conclusion: Marginal Gains at 80 km/h
Iván Romeo’s performance shows how today’s TT riders are mastering not just pedaling technique but every small aspect of aerodynamics and bike setup. His descent during the Dauphiné wasn’t just fast—it was a calculated exercise in blending aero science with on-the-road instinct. Whether TT bikes are always the right tool for fast descents remains up for debate, but Romeo’s example proves that with the right skills and positioning, the gains can be real—and race-winning.
