Tour de Kona – Ironman’s drafting problem

Update: If you’re a triathlete and want to help do something about this problem to ensure that everyone gets a safe, fair race, please fill out Team EMJ’s survey.

Update #2: They’re actually doing something! Sometimes complaining works, or at least maybe helps a bit. 😉

My actual job is as a data scientist, so of course I have a need to try to look at the numbers and try to quantify things. A lot of variables play into how much drafting helps in a triathlon, but we can still look at some general data to get a broad idea of its effect.

First I want to emphasize something: as discussed in my Kona race report, I probably wouldn’t have been on the podium even if there had been no drafting. There were some absolutely incredible performances out there that were 100% clean and there were probably 5 people in front of me who still would have beaten me, such as my teammates Clay Emge and Matt Mallone. I personally know they did things the right way and still had amazing results with top 5 finishes in the age group. Fortunately they also didn’t have to deal with draft packs quite as much because they’re much better swimmers than me and got out on the course before it got as crowded.

But the drafting was a real problem. I’ve dealt with it before and it’s not an uncommon problem, but my personal encounters have been with small groups (like the paceline I encountered at 2017 Ironman 70.3 World Championship – Chattanooga). Kona this year probably wasn’t as bad as the horrors I’ve heard about from Ironman Texas, and apparently it’s not the first time it’s been a problem at Kona, but it was by far the worst I’ve ever personally experienced. For those unfamiliar with the rule, in the non-pro field the distance between athletes should be roughly six bike lengths.

Drafting at IM Texas. Image from Owain Matthews’s blog
Looks like they didnt pay their toll either. Image from Owain Matthews’s blog

I worry that a problem like this could do serious, permanent damage to the sport and devalue the results of people like Clay and Matt if it’s left unchecked. So I want to take a quick look at how much of a problem this is, using some small samples and methods that would never get through academic peer review but that should still provide some pretty strong indicators of how important this is as it relates to actual finishing times and fairness of competition.

Drafting in theory

To start, the case under “ideal” drafting conditions: a cyclist is able to stay tucked into a peloton in great position throughout the race. Most studies show the benefit of this is about a 40% reduction in drag. At the speed of top age groupers (~ 40 km / hr), drag accounts for roughly 83% of total resistive forces, resulting in a 33% reduction of total resistive force from ideal drafting.

From Marco Belloli’s 2016 study
From Alex Simmons, at RST

So let’s take an example rider who weighs about 70 kg and puts out an average of 200 watts during the race. gives a race time of 4:52 on a flat course at sea level with no wind and a good temperature. With a 33% reduction in required power from drafting, the same person can achieve the same speed with the same course and conditions using only 134 watts. This reduction in effort results in fresh legs for the run – it might as well be a standalone marathon. Or, they can stay at 200 watts and bike a Wurf-like 4:11 at the same effort level.

Drafting in reality

Of course the 2nd scenario requires a lead rider or a paceline who can pull at that speed for the whole race. The real outcome in a triathlon is usually a compromise between the two. For example, at IM Texas a top age grouper biked 20 minutes faster with 20% less power (according to a now-deleted Strava file) compared to a recent race with similar terrain and conditions. And then he absolutely smashed the run.

Now, let’s look specifically at Kona. I’m going to use the top 20 as my sample, just because that’s what shows on the 1st page of results and I don’t have time to pull or analyze all the data. In the pro race, where drafting rules were actually enforced, the top 20 men went 4% faster on the bike than last year. Their run times were about the same, resulting in overall race times about 2% faster (making a 9 hour finishing time roughly an 8:50). So they took advantage of the better bike conditions, but did it while putting out about the same amount of effort and leaving the same amount of gas in the tank for the run.

Kona pro bike. Photo: Talbot Cox
And the Kona age group bike…

The top 20 in my age group went 7% faster on the bike and 4% faster on the run, resulting in about a 5% improvement in race times (making a 9 hour finishing time around 8:33, a 17 minute difference compared to what would be expected based on the pro results). Not only were the improvements on the bike much larger than what the pro results indicate the conditions should have produced, they seem to have been produced with less effort, leaving a lot more gas in the tank for the run. The end result was an overall relative improvement ~150% greater than what the pros produced. Some more images of the bike at Kona can be found over on

Sure, you expect outlier performances and for individuals to have significant changes in their results, but the distribution should remain about the same with an offset equal to what was seen in the pro field.

Me? I went 8% faster than in 2017, but I did it while producing 7% more power. I worked my tail off over the past year to get that improvement. You expect other individuals to have similar improvements in fitness, but again not the average. Individual improvements should be balanced out by individual drops in performance, minus the small offset due to conditions. My average power was similar to other recent results like IM Mont-Tremblant, but I suffered significantly on the run due to spikes in my bike effort that I put out for surges to avoid drafting packs. Mysteriously, some people with excellent Kona run times didn’t include their bike power numbers with their race data.

On the bike alone (not accounting for the effect on the run) I did also likely benefit a bit from the draft packs, though. First, as I’m trying to get around the massive groups I am benefiting some from their draft. Second, studies have shown that even the lead cyclist gets a 1% – 2% reduction in drag. I was told by a few people that multiple athletes were gratuitously riding my wheel, so I guess I owe part of my result to them.

I did also admittedly commit a few blocking penalties (re-passing someone before allowing them to fully pass and pull away), swinging far to the outside and trying to pull back away as a group overtook me. Otherwise I would have had to let the entire peloton, which seemed to stretch backwards indefinitely at times, illegally pass me and also provide me with a draft as they went by.

Drafting solutions

The biggest problem right now with drafting is simply the number of people on the course at once. WTC (the company that owns Ironman) has proven time and time again that all they care about is money, not the integrity of the sport. So they try to shove as many people on the course as they can and there simply isn’t enough space for everyone. At some point even if the officials are actively enforcing the rules they’re left with the choice of penalizing no one or of penalizing nearly everyone.

Personally, I vote for the latter. Just like with driving everyone has full control over the space between them and the person in front of them. If someone is not outside the draft zone or actively moving forward for a pass or backwards out of the draft zone, then they’re drafting. Yes, that means either burning a match to get around someone or letting the pace fall off for a bit, but that’s part of racing and having a sub-optimal race is better than compromising the integrity of a race.

The other issue, though, is that heavier enforcement might not even solve the problem. For people with a win at all costs mindset who only care about the visible external outcome rather than the internal achievement, drafting is sadly a logical approach. The probability of getting a penalty times the effect of the penalty are tiny compared to the benefit of drafting. ‘Oh, I got a 5 minute penalty? Ok I’ll stand here and recharge before heading back out to save half an hour sitting on someone’s wheel.’

Like a lot of fouls in sports, there are various degrees of drafting (and unfortunately some subjectivity from the official has to come into play). If it’s “incidental drafting” where someone gets pulled into a pack and is trying unsuccessfully to get out, they can’t quite pass someone fast enough, they don’t quite drop out of the drafting zone before repassing, etc. then 5 minutes is probably appropriate. Even if it’s “accidental,” the fact of the matter is that that rider benefited from that accident and the penalty probably does nothing more than balance out that benefit.

But then there is blatant, deliberate drafting. I’ve seen guys sit right on someone’s wheel, with plenty of space to drop back or make a pass, without even the slightest inclination to do either. For these people, instant DQ. I have no sympathy. None. Get off the course and make room for honest racers. I’ve seen officials observe this behavior from behind for a minute or more, and then do nothing other than pull up next to the rider and motion for them to back off. Really? ‘Oh I see you’re robbing that bank. Well, whatever you’ve already loaded into your van is fine but just please don’t take any more.’

Even in my WoW / videogame playing days I remember rules getting enforced better. Image source

But, a true solution has to come from both enforcement and addressing the issue I mentioned earlier of room on the course. For that, there is no choice but to either have fewer competitors or to move away from the mass start. I love a mass start from a competitive standpoint, but at some point it just doesn’t work. Not only is the swim a chaotic mess, drafting on the bike becomes inevitable. My preference would be to reduce the number of competitors on the course at once and/or see one of two things:

  1. Wave starts based on expected overall finishing time. I’ve seen wave starts based on expected swim time, but that makes no sense to me. I want to be racing the people who will finish similarly overall, not the people who perform similarly for one portion of the race. When I see someone near me during the race I want to know if I’m actually competing with them, rather than it being someone who just started their swim earlier.
  2. Wave starts based on age group. I hate only competing against my age group instead of the best people regardless of age, but if Ironman is going to do all of its results, qualifying, etc. based on age group and not even recognize overall amateur winners, then they might as well be separate races with separate starts.

Another common solution is rolling starts, but I hate this most of all. Similar to the problem I have with waves based on expected swim time, this one means that I don’t know the actual chip time of anyone else on the course. It might as well be an individual time trial.

So my dream solution would be to reduce the number of competitors in championship races, and for other races (or if it’s not possible / appropriate for a championship) do wave starts based on expected overall finishing time. Then once people are out on the course actually enforce the rules, with auto DQs for clearly blatant offenses.

The amount of space wasn’t quite as bad as what appeared in the image shown earlier. As the video shows, there are a lot of people clearly drafting with plenty of room to space out.

Of course another great solution to spread people out would be to just put a long, brutal climb right at the start of the bike course. As a tiny runner / climber on the bike I would love that, but somehow I think that not many people would be on board with that one. 🙂

But how do I really feel about it

In summary: drafting helps. A lot. There was clearly a lot of it going on in the age group race at Kona. And for those who participated, it helped. A lot. Ironman did next to nothing to enforce the rules in their world championship race.

I hate drafters more than dopers. More than course cutters. Drafting helps more, and at least those other types of cheaters have enough shame to try to hide what they’re doing. Drafters just sit right out there in the open and say, ‘screw you, the rules don’t apply to me.’ And if they’re willing to do that out in the open, what are they willing to do in secret?

If Ironman doesn’t do something about this, I genuinely worry that age group results will become meaningless. I’ve put in the work for these races, and I’ve seen the work put in by my teammates and other genuinely honest athletes who are striving for their personal limits. It’s an absolute shame to have that work be ruined by such blatant, open cheating, and even with my departure from the sport I hope that this can be addressed so that triathlon can continue to thrive and produce the kind of experiences, personal growth, and inspiring results that I’ve seen from it.

6 thoughts on “Tour de Kona – Ironman’s drafting problem

  • 2018-10-25 at 6:53 PM

    John – I was big into triathlon from 2005-2009 but haven’t raced since. Your post could have been written almost verbatim 10 years ago on Slowtwitch and it would be true word for word. Clearly WTC doesn’t care, and I assume the bulk of the athletes don’t care either if they keep filling their races. Fortunately you’re coming back to a sport in ultrarunning where you don’t have to worry about any of that!! And you don’t have to deal with the type A tri folks either!

    • 2018-10-25 at 11:57 PM

      Well, it’s nice to hear so many other people see the problem here, but it’s pretty discouraging to hear it’s been a problem for that long. If it hasn’t been fixed by now…

      I’ll still hold out hope, but yup in the meantime I’ll be out on the trails!

  • 2018-10-26 at 10:53 AM

    John, what are your thoughts on fully embracing drafting in draft legal triathlon? It seems like your biggest concern is that it’s illegal so it creates unfair advantages for those following the rules. Draft legal triathlon seems to be picking up traction and while I’ve never raced it, it sounds kind of exciting and competitive. Typically these are sprints or olympic distance, so its a very different race than IM, but if you’re up for a competitive race environment, you would likely find it there! I’ve done a few crits and the drafting component is thrilling, but can also be more risky and dangerous.

    Given your interest and experience in trail running, you should race Xterra! Offroad Tri or Cross Triathlon is so fun, and attracts a unique tri athlete crowd. Most races are 200-300 racers (except for Xterra World Champs in Maui, where there is typically 800 or so) and drafting is a non issue. I’ve been racing Xterra for 3 or 4 years and it has become a great racing family. Come race Xterra Oak Mountain next spring and qualify for Maui and you’ll get a whole new perspective of what triathlon can and should be!

    • 2018-10-26 at 4:51 PM

      It’s fairness, and it’s also safety. That many people together, on TT bikes, who typically aren’t experienced at riding in groups, is a pretty dangerous situation. Draft-legal makes it an entirely different race and both formats should exist. Personally I prefer the no drafting format, but would much rather have legal drafting than illegal but done anyway. I’m also just not a short-distance guy. Whenever I do an Olympic, right as I start to feel good the race is over. That’s also a reason I haven’t done any duathlons despite my lack of swimming ability: other than maybe Zofingen Switzerland they’re all too short for me.

      I have looked at Xterra, and again my issue there is that the distances are too short for me. Also while I definitely prefer running on trails, when it comes to biking I honestly prefer road over mountain. Some of these new Xtri races that seem to have sprung from Norseman look pretty appealing to me, and a lot of them do have road bike + trail run and are on very hilly terrain equal to or greater than iron distance. So if I come back to triathlon or hop into one for fun here or there that’s probably where I’ll end up. My training focus is going to switch 100% to ultras, though.

      Thanks for all the great thoughts and info! I will look into Xterra again and see if there’s one I could hop in.

  • 2018-11-03 at 5:40 PM

    I have only done one triathlon here in Australia. It was an Olympic distance and had the staggered starts. I had people swim over the top of me as it was done by age group so I would prefer to swim with people of my ability. Also it was illegal to draft and there wasn’t any problems. Had a lot of people but not as many as Kona. Everyone basically followed the road rules and kept left unless overtaking.

    • 2018-11-03 at 5:43 PM

      Fortunately there are plenty of races where it’s not a problem, and there are a number of factors that contribute to determining whether it is. If smaller local races like this can maintain a culture of integrity, though, then hopefully that will trickle up to the larger races.


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