Ari Klau just won his first big 70.3. The place was Mont Tremblant, one of the more demanding races on the North American calendar, on a course that rewards athletes who can hold their form when it starts to hurt. It was a class performance, and one that has been coming for a while: he arrived at the race as the top seed after a run of near-misses through the first half of the year, and turned it into a win.
What makes Ari’s story compelling from where we sit is the shape of the journey. He came into triathlon from a D1 running background: a software engineer training seriously on the side, edged toward the sport by an injury and, eventually, a track session with Lionel Sanders in Tucson. He has since built himself into a rider strong enough to win a race like Mont Tremblant off the front. We caught up with him to talk about how it happened, what surprised him along the way, and the setup he is now racing on.
Mont Tremblant
There is a particular texture to the win that closes a run of near-misses. It is not the same as an early-season breakthrough, and it is not the same as a title defence. We asked Ari how the race, and the moment, actually felt.
Q: Tell us about Mont Tremblant. What did the win mean to you personally, and how did the race actually feel, from the swim through to the finish?
It’s a really good feeling to cross the line in first, especially with a lot of near-misses already this year. It was a little different going into the race as the top-seeded athlete in the field for the first time, but that meant I didn’t need to do anything special or have a perfect race to win. I just had to take care of business and perform at the same level I’ve been at all year.
The swim was easy, which I knew meant we had been separated from the front group and were losing time. I’m not strong enough to go around and close the gap to the next group by myself, so my best move was to stay patient and conserve. I had good legs on the bike and the hilly course was especially good for me. I was only a minute or so back at the 33km turnaround and entered T2 just a few seconds behind the leader. The run wasn’t my best but it was more than enough to hold the lead and have some time to take in all the emotions and the crowd support over the last few kilometres.
From Running to Three Sports
Most professional triathletes have to make the switch from a single sport to three at some point in their story. Ari’s version has an unusually specific origin: a track session in Tucson, an off-hand suggestion, and a borrowed set of gear.
Q: You came into triathlon from a D1 running background. When did the transition start, and what pushed you across from single-sport running into three?
I continued trying to run competitively after college while I worked as a software engineer until early 2021. I had been cycling a fair bit by that point due to an ongoing injury, and I have always loved training a lot and training hard, so the idea of adding disciplines on top of running felt natural and exciting.
The ultimate push came in Tucson while I was linking up with Lionel Sanders for track sessions. He mentioned a local tri in Phoenix and said he would lend me all the gear I needed if I signed up. I won the race, and from that point I was hooked.
The Part That Surprised Him
Every transition into a new sport carries a version of the same lesson: the thing you thought would be hard turns out to be manageable, and the thing you did not anticipate at all is what actually costs you time. Ari’s version was fatigue: the way it arrives in three-discipline training, and the way it does not arrive in one.
Q: What was the hardest part of the transition? The bit that surprised you the most about becoming a triathlete after being a pure runner?
I was consistently hitting over 100 miles per week as a runner, but I had never encountered the sheer amount of fatigue you have to deal with in triathlon. Even though I knew I was tired, I still couldn’t comprehend why I was running so slowly, or struggling to push good power on the bike on some of the really tough days. The swings in performance from being tired to being fresh just weren’t that extreme as a single-sport athlete.
Ultimately, this took me years to learn: to set my ego aside and properly adjust the training to account for all the fatigue. Getting fitter helps too.
That last line is worth sitting with. Fatigue management is the quiet third discipline of triathlon, and it is the one that most cross-over athletes underestimate the longest. It is not that runners cannot become triathletes; it is that becoming a triathlete asks you to develop a different relationship with tiredness than any single sport ever does.
Building the Bike Engine
This is the section of the conversation that matters most to a specific reader: the runner who is thinking about triathlon and wondering whether they can ever become genuinely strong on a bike. Ari’s answer is the opposite of the one we expected, and it is the more useful one.
Q: The bike is usually the leg runners find hardest to develop. Yours has become a real weapon. How did you build the bike engine: training, technical work, or a bit of both?
I actually think I might be more of a natural cyclist than a natural runner. My short duration power, from around three minutes up to 20 minutes, has always been very good. Unfortunately, triathlon is not a punchy 10-minute climb on a road bike, so it took several years to develop the endurance to ride hard for two hours while holding a great aero position.
The engine was always there, but the specific leg muscles and physiological adaptations that I needed took a while to develop, and I am still heavily in that process of improving as a long-distance time trialist.
Learning the TT Position
A runner’s body arrives at the TT bike with a specific set of habits. The TT position is where those habits get renegotiated. Ari’s answer here is a piece of practical prescription that should probably be printed and taped to a lot of pain caves.
Q: What was your approach to the TT position as someone relatively new to the bike? Was there anything you had to unlearn from your runner’s body, and how did you get comfortable in the aero position?
In my opinion, there are two keys to good time trialling as a triathlete. The first is a good bike fit. The second is riding in the TT position basically all the time. I do 100 per cent of my intervals in TT position, sometimes doing reps as long as 90 minutes straight on the turbo without leaving the aerobars.
It feels extremely uncomfortable at first, but if you just commit to staying in the bars for really long periods, the body will adapt until it feels natural.
That two-key formulation (good fit, then discipline of staying in the position) is about as clean an expression of the position-first method as we have heard from an athlete on our roster. The comfort you race with is not something you buy; it is something you build, one long turbo rep at a time.
Inside the AB03
The AB03 was designed around a single principle: the cockpit should move with the athlete, not against them. For an athlete still refining a relatively young TT position and adjusting it as his engine grows into it, the tunability matters more than the spec sheet ever could. We asked Ari how the AB03 has actually felt on the bike.
Q: You are riding the Sync AB03. How has it felt under you? What has it added to how you race, and how does it fit into the position work you have been doing?
There’s a lot that I love about the Sync AB03. I’ve admired them from afar on social media for years because of how sleek and beautifully engineered they are. They’re incredibly light, which has made the weight distribution more central on my bike, so it now handles much snappier. And we saved 13 watts over my previous setup once we got the bars dialled in at a recent aero testing session.
Because I’ve been racing every month since March, it’s hard to make any major positional changes since there isn’t enough time to adapt, but I’m excited for a break in racing after 70.3 Boise in July to work on this. The comfort, stability and adjustability of the AB03 open up a lot of doors for getting into an even more aggressive TT position whilst keeping it sustainable, powerful and, consequently, faster.
A word on that 13-watt figure. It is Ari’s number, from Ari’s previous setup, in Ari’s position, at a single testing session. It should not be read as a universal claim about the AB03 or any other cockpit. It is exactly the kind of individual result the position-first method produces, and exactly the kind of thing that will look different on a different rider. What matters is not the number in isolation; it is the process that produced it.
The Rest of 2026
Q: What is next for the rest of 2026? Where are you pointing?
Next up is 70.3 Boise at the end of July, then two long training blocks into 70.3 New York and 70.3 La Quinta. We may or may not try an Ironman somewhere in there, but I leave decisions like those up to my coach. The goal is to be in the mix for the win at all three of those races, and to secure my slot for the 2027 70.3 World Championships in Chattanooga.
