Jeff Dieffenbach has 5 recorded races from Cambridge, Massachusetts, US.
| Date | Race | Distance | Time | Overall |
|---|---|---|---|---|
| 2023-07-28 | 2023 Stages Cycling Leadville Stage Race Stage Race Solo - 3 Day Totals | Ultra Marathon | 10:45:59 | 220 |
| 2023-07-28 | 2023 Stages Cycling Leadville Stage Race Day 1 - 40 Miles | Ultra Marathon | 3:49:55 | 248 |
| 2023-07-28 | 2023 Stages Cycling Leadville Stage Race Day 2 - 20 Miles | 3:02:17 | 222 | |
| 2023-07-28 | 2023 Stages Cycling Leadville Stage Race Day 3 - 40 Miles | Ultra Marathon | 3:53:47 | 195 |
| 2023-07-28 | 2023 Stages Cycling Leadville Stage Race Days 1 and 2 Totals | Ultra Marathon | 6:52:12 | 229 |