Dave Mackey's R2R2R record held for about 4 years before being broken by Dakota Jones who ran 6h53m38s on Nov. 5, 2011. Jones reported on his blog as follows: "...Mackey was held up for several minutes during his record run on the way back up the South Rim by a mule train. A similar thing happened to me, except that instead of a mule train I was held up by being astoundingly tired. I ran hard, but never felt like I was approaching my comfort zone until the final climb, when I entered the suffer zone and then fell into the abyss of despair. From the few reports I have read as well as my own two experiences running the Double Crossing, two facts seems to be permanent for all runners: 1.) Nobody goes into it rested. Everybody just runs the Grand Canyon as a training run, or in between races, or when getting back into shape. Nobody trains and tapers specifically for the Grand Canyon. 2.) You're going to blow up on the ascent back to the South Rim. Stop deluding yourself - it's going to happen. You can't avoid it. However, I will stick my neck out and say that a fit and rested runner who finds the Canyon in good condition could significantly lower the time. My prediction is that within five years the men's record will be under six hours. Go ahead - call me out on that. It will happen." Jones also reported the following splits: River(49m), North Rim(3h22m), River(5h12m), South Rim(6h53m38s).
6h 53m 38s