Just curious…I am sure this has been talked about ad nauseum here but I am interested in what your marathon pace vs. IM pace was in your first race. If I do a 3:10 marathon, I can expect with a solid swim and bike what…around 3:40 or so? Or 5+ when my GI tract shuts down at 17 and I walk 9 in 
Ran 3;09 in october. Was much more fit, maybe 2:55 - 3:00 shape come IMWI next sept (first ironman). “ran” a 4:53 whilst vomiting quite a bit.
now THAT is what I dont want to hear
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I swam and biked very easy too. Thing is I just turned 20 when doing the race so I don’t think my body was conditioned to exercise for that long. I’m sure if you have more lifetime miles under your belt it wouldn’t be such a shock.
3:12 IM run in November, 2:48 stand alone the following March.
Both runs were done close to as well as I was capable of doing on that day. No major bonk or GI issue either time.
So based on my particular experience, 12 to 15% over stand alone. So I’d say you’ll do 3:35 to 3:40 if you do everything right. If you don’t, its anybody’s guess. Good luck!
I run just under 3 hours for an open Marathon. My 1st IM “run” was 4:15. My second was 3:42. My goal is to get to 3:30 for my next one or the one after that…
First IM marathon was 3:36 under ideal (for me) race conditions (cool). Ran the whole marathon including the water stops. Previous to that best marathon was 2:59, ran a 2:54 2 months after the IM. 2:54 was also ideal (for me) race conditions.
Haven’t come close to either of those times since then…
George
First IM marathon was 4:09, 4 months after a 3:39 stand alone marathon.
I’ve improved every IM since, last IM marathon was 3:39.
Apart from getting your nutrition right, my key tip would be to focus on not going out to fast in the first half of the IM marathon especially the first 10k, and to keep your cadence around 90.
2:54 open, first IM was 4:08. Same year just a few months apart. There was a lot of walking…
Just add an hour and be super happy if you go under that time. Enjoy the day.
Marathon PR (after 15 marathons) is 2:41. First and only IM marathon last year was 3:10. Only a very tiny bit of walking for maybe 20 seconds.
I accidentally went out much too fast in that IM marathon. If I had not done so I think it would have been closer to 3:00. But then again, woulda, coulda shoulda
If I do a 3:10 marathon, I can expect with a solid swim and bike what…around 3:40 or so?
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Funny, you sound like me circa '08. Same season, 1st marathon & 1st IM…3:12 & 3:41.