My half marathon PR is 1:25:01 but my full marathon PR is…3:38:11.
Granted the half PR is the more recent race, but both times were run within a year of each other (10 months) and although I did not run a tune-up half prior to the full, I was probably in 1:30-1:35 shape at the time. I tried to run 3:15 but crashed and burned miserably.
I have no immediate plans to run another full, so I'll be stuck with a 3:38 PR for awhile longer. 1:25 vs. 3:38 is a pretty huge difference. Any other runners with a similar gap?