Ironman vs Marathon

As some of you know ive entered The Longest Day 2004.

As my main experience of training and competing is running I want to be able to try and compare Marathon times to Ironman times.

What I am trying to say is, What sort of time should I be capable of running 2004 London Marathon in if I am to use it as a barometer relating to my likely success at Longest Day assuming I am following a balanced Ironman training plan.

My target for LM 2004 is around 3.20 - 3.30. With the balanced training in mind what could I estimate my Ironman finish time to be (though im only aiming to finish within the 16hr cit off, 13 hrs would be nice).


  • how much running have you done? what's your current marathon time?
  • I would guess you might easily be sub 11.30. This year I did just over 14 hours with hardly any running in my legs before the race (73 miles logged between end of March and race day). So 13 hours should be a doddle for you. However a lot depends on your bike section. My friend, who generally runs around 3.30 marathons finished in 11.52 - he is fairly strong on the bike, would consider himself as average on the run and is a very weak swimmer. Hope this gives you some idea.
  • Lots between 1999 & 2002, best Marathon time is 4hr06. Im training much harder and have started earlier this time, im very confident sub 3.30 is realistic.

    I was entered for FLM 2002 but pulled my hamstring Nov 2001 and after a 4 month lay off (Marathon cancelled) I got a very bad verucar which took 8 months to get rid off. Hence im only back to training from July and thought ill go for a more substancial goal and challenge myself to train for an Ironman in 12 months.

    If I can stay relatively injury free I should be well ahead of any previous training schedules ive followed and be able to do a 1hr 40 Watford 1/2 marathon (in lat jan early feb) vs 1hr 50's which ive done before.

    I think ive got the running more or less covered as have prior training experience, as ive said in the other thread im concentrating on swimming at the moment, but have been advised to get more bike miles in which I will do.
  • i dont think you can predict it from run time.... there are runners, cyclists and swimmers - three very different events

    i'm a passable runner, a good cyclist on a flat course (training on one), a reasonably good cyclist on a hilly course and a pants swimmer

    everybody is different

    also doesn't matter how good a runner you are, its how good a runner off 5 hours cycling
  • Im the opposite

    I'm a good swimmer
    A carp biker (will fix this)
    and a Carp Runner (4hr marathon)

    The only thing you can base on your marathon tim is that it will probabaly take you 20% longer at the end of an Ironman
  • Only 20% lol, I was thinking id have to crawl the last 10 miles hehe.

    Actually, thats worth knowing. Is the 20% extra a good rule of thumb?
  • Add 45 mins to your marathon time - that's seems to work pretty well, unless you really blow up.

  • My marathon PB is 2:42, and my best "Ironman marathon" is 3:40 - but it was a hilly course and I had the sh*ts! - so if I hadn't stopped 4 times for the portaloo, I reckon 3:25 to 3:30 is more like it.
    Difficult to predict imes as lots can happen - it's a long day!
    FWIW - I passed 468 people in the run - they obviously had better swim / bike legs than me, but couldn't run as well.

  • Sorry Paul

    But i just had a laugh of the image of you basing your run on "Lets just get to the next loo"

    Not nice i know but funny :o)
  • It was quite funny - it was IM OZ, and the run was 2 laps, so I used 2 portaloos twice, and the Aussies "manning" them were p*ssing themselves laughing - too many energy gels I guess!! :o)

  • Carl,
    My best marathon time is 2-52, but my 1st IM marathon (Longest Day) was just under 4 hours (overall time of 11-05). I have since improved to 3-31 for the run as part of an overall time of 10-31, but this was achieved by increasing the cycling training, not the running - I think I actually ran fewer miles that year. The point is that it doesn't matter how good a runner you are if you are totally wrecked when you get off the bike, you need to train properly on the bike to give yourself a chance on the run.
  • It seems as if everyone's experiences are pretty similar. My best marathon is 2.57, my first Ironman marathon split was 3.57 (overall time 11.20). My focus for next year is to improve the bike leg so that I can gain time but more importantly hit the run leg feeling fresher.
  • It all depends if you can run off the bike. I ran 4hrs at my first IM when in about 3:30 standalone fitness. But I am a crap cyclist and suffered badly on the bike. If you get the longish bricks in you will get closer to your standalone time. People I know vary between 20-30 mins slower which seems about right to me as long as you train for running off the bike
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