Christof announced the first attempt of a Quadruple R2R2R (4xR2R2R, or R2R2R2R2R2R2R2R2R), and posted details to http://www.christofteuscher.com/aagaa/news-grand-canyon-r2r2r2r2r2r2r2r2r-attempt
"To the best of my knowledge, this has never been attempted. There may be a (good) reason for that. I guess I’ll find out. A single south-to-north rim-to-rim crossing on the Kaibab trail is 21 miles long with about 6,000ft of elevation gain. Going the opposite way results in about 5,000ft of elevation gain only. 8 crossings thus add up to 168 miles with about 44,000ft of elevation gain. This will be a supported attempt, because, well, I’m getting old, feeble, and lazy."
Christof started at 4:04am on 10/24.
R2R at about 5h26m (9:30 on 10/24)
R2R2R about 11h01m total (15:05 on 10/24)
R2R2R2R at 18h36m (22:40 on 10/24)
R2R2R2R2R (double R2R2R) at 26h32m (6:36 on 10/25) "After a horrible night and another quick pit stop at the South Rim at dawn, heading back down into the canyon. The view is ok."
R2R2R2R2R2R (N Rim) at 34h22m (14:26 on 10/25).
R2R2R2R2R2R2R (triple R2R2R) at 41h14m (21:18 on 10/25). Whoa - sub 15h for the 3rd consecutive R2R2R! Nighttime will be hard. Go Christof!
R2R2R2R2R2R2R2R (back on the N Rim) at 51h09m (7:13 on 10/26). One more crossing!
R2R2R2R2R2R2R2R2R - Complete! 58h10m (14:14 on 10/26). Wow!