Sub7 hour Ironman – is it possible?

When I heard about the Pho3nix Sub7/8 hour project, my initial thought was; Ironman under 7 hours? Thats not possible. Not today at least with the equipment and rules we have. It would take a world-class open water swim, a bike leg with unheard average watts and the fastest marathon in any full distance triathlon ever. There is no way I can see this happen unless something revolutionary happens with aerodynamic.

It could be completed with the following splits:

  • 42 min swim
  • 3 hour 47 min bike
  • 2 hour and 30 min marathon 
  • 59 seconds total in T1 and T2

Roughly that would be an average of

  • 1:06 min/100m swim
  • 340 watts average bike (with superb aerodynamics)
  • 17 km/h average run

There is no way that is going to happen! And the Pho3nix Sub7/8 project seems to agree with me. It cannot be done except from a revolution on the equipment side.

For that reason the race is not completed within regular long distance triathlon rules. Pacers are allowed and most importantly, drafting is legal on the bike. That makes the race incomparable to a normal full distance triathlon. Its also the reason why the Ironman(distance)-fan in me revolted when the project claimed they would destroy Jan Frodeno’s long distance record, standing at 7:35:39. With a draft legal bike the times cannot be compared. Going sub 7 hours on an Ironman distance is not hard if you can choose your own rules. With an AeroVelo ETA bicycle I would manage 180km in about 1h and 45 minutes with comfortable 250 watts in average. If I could find a course with strong current and a run with downhill I believe that around 5h and 15m Ironman should be possible. 

Aerovelo ETA has a CdA og 0,012, compared to 0,2 for world class triathletes and would make it doable for a lot of athletes to go Sub7.

With that «grumpiness» said I will move on to what I believe about this awesome project. Because the rules are not set to make a sub7 hour easy. As my understanding from the MX Endurance podcast the rules are as following:

  • Up to five pacers on the swim and with the possibility to have thicker neoprene suits to increase bouyance
  • Up to five pacers on the bike were drafting is legal (but you can only have the same five pacers for the whole 180k)
  • Up to five pacers on the run

Otherwise its a looped or out at back course (Daytona was one option they looked at) which is TBD. Aka, no net downhill race or swimming with a positiv current.

Its going to be very entertaining for sure, and truly interesting to see the different tactics Alistair Brownlee compared to Kristian Blummenfelt. Alistair said that its 99 % chance that sub7 is not reached but he is going for that 1 %. Kristian is more confident. 

Personally I will put the odds similar to Alistair, 99 % chance of not going sub7. If the swim is «only» a 44 minutes swim instead of 42 in increases the watt demand for the biker with 10 watts. And my calculations are based on a real life CdA of 0,2, which could be tough for a rolling TT-team including drinking, eating and peeing. If that goes as planned the athletes «only» need to run a 2:30 marathon. They are surely both very capable of running a stand alone 2:30 marathon with ease, no doubt about it. Since the fastest IM marathon to date is Matt Hanson’s 2:34:39 it seems that hard swim followed 180k with high intensity in aero position does something with the legs and energy level. The 180k bike would be substantially easier than Brownlee and Blummenfelt is capable off (you cannot fint cyclist that would make it hard for them to just stay in the draft), but 180k does something on the legs on a muscular level still.

My rather bleach forecast of the result must not be confused with being negative to the project. It’s going to be exciting, it’s going to push boundaries, it’s forcing some of our greatest athletes to take a proper look into performance optimisation and it’s going to create attention and raise money/awareness for a good cause. My bowl with popcorn is ready 😀 And most importantly, it raises awareness of the importance of physical activity to increase wellbeing and health (especially children in disadvantaged situations)

And when it comes to the Sub8, that should not be a problem, because its «only» 18 minutes and its easier to find female cyclists who can gap that compared to the mens. 

For more details about the project check out the MX Endurance podcast with Macca’s thoughts about the project. 

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I am a 33 year old PRO triatlete. My goal is to swim, bike and run as fast as possible, and enjoy the journey. All my adventures and triathlon related stuff is well documented on this blog.

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