Most runners chasing a sub-24 at a US 100-miler have the fitness. What they don’t have is the pacing discipline. The difference between a 23:50 finisher and a 25:30 finisher is rarely fitness; it’s how the first 50 miles got run.

Sub-24 averages out to roughly 14:24/mi. That sounds slow until you remember it includes every aid station stop, every pee break, every gear change, every walked uphill, every dark-of-night moment of self-doubt. Sub-24 is “moderate effort with no major breaks.” The runner who hits 11:30 pace through mile 40 and then sits at every aid station for 8 minutes runs 25 hours. The runner who hits 13:15 pace consistently and is at aid stations for 4 minutes runs sub-24.

The split that works

For most American 100-milers (Western States, Leadville, Rio Del Lago, Run Rabbit Run), the sub-24 split looks like this:

  • Miles 0–30: 11:00–12:00/mi pace, feels insultingly easy
  • Miles 30–60: 13:00–14:00/mi pace, feels comfortable
  • Miles 60–80: 14:00–15:30/mi pace, feels honest
  • Miles 80–100: 15:00–17:00/mi pace, hike the climbs, run the descents and flats

That’s a negative split inverted — slow finish, but average to sub-24. The classic mistake is reversing this: 9:30/mi for 30, then walking the back half. That’s a 26-hour finish.

The aid-station math

Six minutes at twelve aid stations is 72 minutes. That’s an entire hour of your sub-24 budget. Cut it to three minutes per stop and you save half an hour. Crewed runners save more — drop bag pre-organized, vest pre-stocked, a chair waiting, food handed to you in your hand without asking.

Most sub-24 finishers have a crew that runs aid stations like a NASCAR pit crew. It’s the unsung half of the buckle.

What sub-24 doesn’t require

It doesn’t require 100-mile training weeks. Most sub-24 finishers peak around 80-85 miles per week. It doesn’t require quad strength workouts in the gym. It doesn’t require carbon-plate trail shoes. It doesn’t require a coach.

What it requires: 24 weeks of consistent training with two long-run days per week, vert specificity (training on grade similar to the race), meticulous fueling discipline, and pacing patience. The boring stuff. Sub-24 isn’t athletic; it’s executional.

The runners we’ve seen miss sub-24 in races where they had it in the legs always tell us the same story afterward: “I went out too fast. I knew I was going out too fast. I felt great. Then I bonked.” The first 30 miles is where the buckle is won — by holding back, not pushing.

One last thing

If you’re chasing sub-24 and have the fitness, don’t try to “feel out” the pace early. Wear a watch with a target pace bar. Discipline yourself to the slower number. Your watch will tell you you’re behind schedule at mile 25 — that’s exactly correct. The schedule is wrong; the pace is right. Trust the math.

The buckle is heavy in the right way. We hope you earn one.