Tomorrow, the world's elite triathletes return to Kona for the Men's Ironman World Championship. The last time the pro men battled on this iconic course, Sam Laidlow shattered the bike course record, slicing nearly five minutes off to set a new benchmark of 4:04:36. This blistering time was a masterful blend of aerodynamic efficiency and raw power. At Best Bike Split, we've delved into Sam's record-breaking performance, using his power data (Average Power 311W, Normalized Power 318W) to determine his CdA—a remarkably low 0.205. With this insight, we're exploring what it will take to go even faster this year.
Take a look at the Kona Sub-4 Model that we will be referencing below.
To predict this year's race dynamics, we started with Sam's baseline CdA and equipment setup from 2022. Leveraging our Advanced Weather feature, we pulled the latest forecasts for race day. Then, using our updated Goal-Time-Based model (now enhanced with a Minimum VI setting for hilly and off-road races), we set a target time of 4:04.
The model reveals that to break the current record, an athlete would need to average 315 watts, with a normalized power of 322 watts. That's just 4 watts more than what Sam pushed in 2022. It might not sound like much, but at this elite level, every watt counts.
One of the most significant factors at Kona is the weather—specifically, the wind. Contrary to what you might expect on an island, the prevailing breeze comes from east to west. The Big Island's towering mountains create fascinating and often confounding wind patterns. As the wind wraps around the island's north side, riders face a headwind on the climb up to the turnaround at Hawi.
On the return leg, the wind, which intensifies throughout the day, is funneled between the mountains, shifting to a fierce crosswind that has been known to blow riders off course and disallow disc wheels in the race. However, pro athletes often manage to "get ahead" of the worst winds, which has led to faster times in recent years.
According to our weather data, the pros are forecasted to face a slight headwind of about 6 mph on the way back to the finish before it shifts to a much stronger cross/headwind later in the day. This window of opportunity could be crucial for anyone aiming to break the record.
So, what would it take to break the elusive 4-hour barrier on the Kona bike course? Using Best Bike Split's Time Analysis Tool, we conducted a "what-if" scenario to estimate the required power output. The results are staggering: an athlete would need to average approximately 328 watts, with a normalized power of 335 watts.
While not impossible—given the continual advancements in training and performance—the intensity factor (IF) and training stress score (TSS) associated with such an effort could severely impact the marathon that follows. Pushing that hard on the bike might lead to struggles on Kona's brutal run course.
Another variable to consider is the ongoing evolution of aerodynamic gains. Sam Laidlow is already exceptionally aerodynamic, but new positions and equipment innovations from former Ironman World Champions Kristian Blummenfelt and Gustav Iden could potentially lower the power needed to break 4 hours significantly.
With all the intricacies of the Kona course, how do athletes prepare for the unpredictable wind and harsh conditions? At Best Bike Split, we've been obsessed with helping athletes tackle this question. This past year, we've launched two new AI-powered features to assist in race preparation.
First, our AI Assistant provides members with deeper insights into their race plans, offering guidance on nutrition, pacing, and specific training focus areas. It's like having a personalized coach that helps you optimize every aspect of your performance.
Additionally, we've introduced AI-structured workout building in collaboration with StructuredWorkout.com. This feature allows athletes to generate customized workouts tailored to their race plan and individual needs. We've even added a selection of featured workouts specifically designed for the Kona course. Whether you're competing or watching from home, you can experience a taste of the challenge by riding these workouts.
To access them, log into your Best Bike Split account, navigate to the Workouts section, and select "Workout Library." From there, you can add them to your account and sync with Garmin, Wahoo, or TrainingPeaks, or download files to use with Zwift or TrainerRoad
We're incredibly excited to watch the world's most amazing triathletes battle it out at the pinnacle of the sport tomorrow. We invite everyone tuning in to try out our featured AI-created Kona workouts and check out our record-breaking model. Don't forget to explore our new 3D mapping features and use the Time Analysis tool to see how you would perform on this legendary course.
Whether you're a seasoned athlete or a passionate fan, Best Bike Split brings you closer to the action. Let's see who will rise to the challenge and whether we'll witness a new record—or even a sub-4-hour bike split—at this year's Ironman World Championship in Kona.
Take a look at the Kona Sub-4 race plan where you can use the Time Analysis tool to see how you would do by varying drag (CdA), power and/or weight.