Pacing an IM Marathon

Essentially, your "easy" running pace is probably a good target for your IM marathon.  This assumes that you have good swim & bike fitness and that you've paced those appropriately as well.  Check this table out for a decent stab at it.

Determining your Ironman run pace is an interesting experiment, particularly because you will be walking.  I know you WANT to run the whole thing, but few and far between are people that actually run it door to door.  You may hear the add :30 minutes quoted as a means of determining your run leg from a full marathon time, but that did not apply in my case.  I turned in a 11:23 in my first IM by running a 4:20 marathon, which in hindsight I was suffering from going out on the bike too hard.  I ended up averaging 9:53's which was about 2:20 per mile slower than my marathon time!  This is not good FYI

Below are two links, one which gives a good overview on race tactics and one which will calculate a project time based on training volume and recent time trial performances.  I have found the calculator to be fairly accurate.

http://www.endurancecoach.com/Ironman_Race_Tactics.htm

http://www.triathloncalculator.com/

I had always planned to take the 1st quarter of my IM ride and run real easy. After cramping in the swim I was sore and very tentatve about the rest of the day so took them both even easier then I planned to.

Ended up EXACTLY with even splits on both the ride and run. The first quarter feels stupidly slow and easy but it pays off.

Gerrard

When I did IMFL last year, I was pretty much in the same situation. Not sure what to expect from the run. My most recent standalone marathon had been a 4:09, but I had not performed that well on the run in any of the 3 HIMs I did in the 18 months leading up to IMFL. So, I based my anticipated pace on my HIM times and figured I would run the marathon at IMFL in about 6 hours.

My swim was exactly what I had planned for.

My bike was right in the time I had targeted.

I ran the marathon 1 hour faster than I thought I would!

When I got off the bike, I figured running would be tough, but I felt great, and took off at quite a good pace (for me). Initially, I had a brief conversation with myself about slowing down and saving something for the end, but then, discarded that idea as the easy way out, and decided I would run as strongly as I could for as long as I could (and walking through the aid stations). I hit the halfway mark around 15 minutes faster than I had run the same distance in any of my HIMs! I wish I could have kept it up, but I definitely started to slow down on the second half and my legs were screaming at me; however, I kept right on running. I did the marathon in 4:56:xx, exceeding all of my expectations.

So, I say have some idea of what you think it might be based on your other races, but be prepared to perform better (or, perhaps, worse). Looking at your times, I would target a 10 min/mile pace, which, for you, should be pretty comfortable. If you feel you can run faster, then I say go for it. A lot will depend on how you feel getting off of the bike.

And have a great, great race!