The Long Run: Ironman Marathon vs Standalone Marathon
You've run a marathon, finished in a pretty decent time, and now have your sights set on racing an Ironman. What should you expect your ironman marathon time to be? We crunched the numbers and the results are in Triathlete Magazine's December 2011 issue.
A sneak peak is below. Short answer: add 20-30 minutes, for starters.