Someone told me that in gross terms, you can look at your HIM time X 2 plus 30 minutes to get a read on what your IM time might look like. That sounds too aggressive, and obviously there are tons of variables. Wondering what those who have experience at both distances think the factor might be?
I certainly don’t think that there is a way to calculate this with any real accuracy…I would say double plus 1 hr would be closer but the two distances are extremely different…training is different, variables throughout the day, mental strength, etc…
I’ve been told 2 x HIM + 1 hour. I don’t really have a lot of results to back this up, though. I’ve done two IM’s, but the only HIM I did before them had a shortened bike course…
Almost exactly (to the minute) 2x+1 hour for my one IM effort. But I suspect it varies based on training, goals, conditions, and a ton of other factors.
I used the 2xHIM + 1 hour time to set my “reach” goal. It was very accurate, although I am sure there was a little bit of bias in there as once I set the goal, I was aiming to hit that time.
HIM (Eagleman) 5:01:36
IM (Louisville) 10:58:34
On the other hand, I was way behind on my biking and had a bit of a cold for Eagleman, so the 2XHIM +1 hr is fairly aggressive and assumes you put in all the distance training expected for an IM.
2(HIM) + 1hr works for my times.
Went 4:49 at Lake Stevens
Two weeks later went 10:35 at IMLOU
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This year for me:
HIM: 5:32
IM: 12:07
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Let’s face it, you can’t use some stupid formula to figure out your HIM time from IM and the other way around. Sure you can play with numbers but an IM is a different event from a HIM. Can you use a formula to find your marathon time from a 100m sprint?
The factor is that a HIM is a different event from an IM distance race.
Let’s face it, you can’t use some stupid formula to figure out your HIM time from IM and the other way around. Sure you can play with numbers but an IM is a different event from a HIM. Can you use a formula to find your marathon time from a 100m sprint?
The factor is that a HIM is a different event from an IM distance race.
I did a 100M today at the track and clocked at 9.57 into the wind. . so I figure my marathon time should be 2:00.59 or somwhere around there.
Wow, so those formulas do work 
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But you could predict a marathon time from a 1/2 marathon time. Couldn’t you?
People say the Ironman is a different beast than a 1/2 which it is! But I think you can get a pretty close guess by taking a
The 2x +1 works, but you have to take into account the course, and there are all the other factors, such as heat (or cold), current, etc.
For instance:
IMNZ '09 10:47
Wildflower '09 5:20
RI 70.3 '09 4:52
(backwards in the timing with NZ in March, but…)
Vineman 70.3 '07: 4:55
IMLOU '07: 11:42 or so (and 95° starting the run)
So 2x +1 didn’t work all that well in my case, though you could take vineman '07 and hit IMNZ pretty well 2 years later, and RI was close, but had I done vineman instead I personally think vineman is a faster course, so I would have been more like 4:40.
So use it as a ROUGH guide, only if the course is similar, and race day weather is not way off.
Rob
I think x2+1 a pretty decent guideline to get you in the ballpark.
It’s a safe bet if you do a 5 Hr half that you are not going 10 HRS flat, but you probably won’t go over twelve unless you had some problems or a bad day.
Obviously Courses and weather play a factor, but that’s such common sense it should not need mentioning.
I break it down roughly like this:
- Swim is a few minutes slower + transitions tend to be longer = + 5 min.
- Run in half IM = marathon pace. Run in an IM = marathon + 20-30 min. = + 20-30 minutes (I use 30 min).
Going back to 2 ) Bike - it depends a lot on your speed. If you’re a pro - you may ride a half IM at 320 watts and an IM at 280 watts. If you are like me, you may ride a half IM near 200 watts and an IM at 160 watts. Speed-wise 320 vs. 280 isn’t that much yet 200 vs. 160 is a couple+ mph…
If you ride a 2:10-2:15 half IM - you’ll ride maybe 10 minutes slower (half IM x2 + 10) for an IM.
If you ride a 2:40 half IM - you’ll ride maybe 30 minutes slower.
So I’d say if you can crush the bike - maybe 30 minutes slower overall and if you are like me - closer to 60 minutes. The slower you are - the bigger the spread :).
Dave
I think x2+1 a pretty decent guideline to get you in the ballpark.
It’s a safe bet if you do a 5 Hr half that you are not going 10 HRS flat, …
Agree. But it suprising how many people do not have that come to Jesus talk with themselves. That is, they talk themselves into, “Well I did 5 in the half and I will train a lot more before the full, so I can go sub 10 on my way to Kona”.
Agree with most people’s assessment of the X2 + 1 hour. Mine was actually faster than that, but it should get you in the ballpark of your physical capabilities. However, depending on variables like conditioning, course, weather, good/bad day, etc…it can obviously change. Unless you had a bad day, were injured, or similar during your HIM, I think X2 + 30 minutes is optimistic, but definitely not impossible.
There is actually a fatigue curve formula that might be useful. Its usually done with only one sport though. Check out “championship triathlon training”. You can figure out your marathon times base off as little as a 5k. Not sure how accurate HIM to IM will be unless they are both on similar coarses, temp, time of the season(peaking) etc.
5:23 White Lake Half II (fast & flat yet was 95+ on the run)
12:03 IMLoo (fast, flat, absolutely perfect weather)
On my first IM at Louisville this year, I sandbagged the bike a fair amount because I really wanted to make sure I had enough to run well for the Mary. My marathon time was 4:06. If I had pushed a bit more on the bike and struggled on the run I figure i could have dropped 10 minutes. Oh well, theres always next time
It’s pretty consistent for me
Fastest of each (in the same year AG 60+, (not this year unfortunately)).
Sprint ? (who cares)
2:26 Oly
5:32 HIM
11:40 IM (flat course)
Pretty well +40 for each.