Leadville 100 Cutoff Times: The Math Behind a 30-Hour Finish¶
The gun goes off at 4:00 AM on August 22. In just over four weeks, you will be in the dark on a dirt road in Leadville, Colorado, running toward a turnaround at 10,000 feet while a clock counts up from zero.
You've done the training. The question sitting with most Leadville runners right now, in taper, is a specific one: do the numbers actually work?
You have a Strava log. You have time on feet from long runs. What you may not have yet is the arithmetic connecting that training log to the three timestamps that determine whether you finish. This post does that arithmetic, station by station.
The three timestamps that end races¶
Not every Leadville aid station cutoff carries equal weight. There are twelve cutoffs in total on the official chart. Three of them account for the majority of DNFs:
| Aid station | Mile | Cutoff time | Hours elapsed | Required avg pace |
|---|---|---|---|---|
| Winfield (turnaround) | 49.8 | 6:00 PM Sat | 14h 00m | 16:52/mi |
| Twin Lakes Village (inbound) | 61.8 | 10:15 PM Sat | 18h 15m | 17:43/mi |
| Mayqueen (inbound) | 87.2 | 6:30 AM Sun | 26h 30m | 18:14/mi |
The other cutoffs, Half Pipe inbound at 1:15 AM (mile 70.3) and Outward Bound inbound at 3:00 AM (mile 76.2), also exist. But if you're making Mayqueen, you're almost certainly clearing those two as well. The three stations above are where runners run out of race.
Winfield is the first hard wall. Twin Lakes inbound is where late-race attrition concentrates, the second Hope Pass crossing at night on tired legs. Mayqueen inbound is where the 30-hour window either holds or collapses for good.
What those timestamps actually demand, mile by mile¶
The average pace requirements in the table above are calculated from the gun. That's useful as a floor, but the real math is in the segments, because you're not running at one even pace across 100 miles of mixed terrain and 10,000-plus feet of climbing.
Winfield, 6:00 PM (mile 49.8)¶
Fourteen hours from the gun to cover 49.8 miles, including the first crossing of Hope Pass at 12,600 feet. The required average of 16:52/mi from the start is the floor. Most runners who make Winfield arrive with buffer, not exactly at the cutoff.
The reason buffer matters here: the 12 miles from Winfield back to Twin Lakes inbound include the return crossing of Hope Pass, now going up the far side, at night, on legs that have already covered 50 miles at altitude. Arriving at Winfield with 30 minutes of buffer before 6:00 PM is not arriving safely. Thirty minutes disappears fast on Hope Pass in the dark.
Aim to reach Winfield by 5:15 PM (45 minutes of buffer). That's 13 hours 15 minutes from the gun, an average of 15:58/mi from the start. Before the race, check whether your training data supports that pace once adjusted for altitude.
Twin Lakes inbound, 10:15 PM (mile 61.8)¶
The cutoff allows 4 hours 15 minutes for the 12-mile stretch from Winfield to Twin Lakes inbound. That is a 21:15/mi average for that segment alone.
That sounds forgiving until you're on it. The segment crosses Hope Pass a second time, now ascending the steeper Winfield side (which was the descent on the outbound), at night, somewhere between mile 50 and mile 58. Runners who arrive at Winfield with no buffer and then lose time on the second pass routinely hit the Twin Lakes cutoff and get pulled.
At sea level on flat ground, 21 minutes per mile is barely faster than a deliberate walk. At 12,600 feet in the dark on rocky trail after 50 miles, it is the pace you need to maintain to still have a race.
Mayqueen inbound, 6:30 AM (mile 87.2)¶
From Twin Lakes inbound to Mayqueen is 25.4 miles and 8 hours 15 minutes: a required segment pace of roughly 19:30/mi.
This is where the "I'll make it up later" math collapses. Miles 61 through 87 cover ground in the dark, past Half Pipe and Outward Bound, during the hours when most runners hit their lowest point. The segment pace is not slow. It requires consistent movement. Runners who sit at Twin Lakes or slow dramatically in the night section burn the window here.
The 30-hour finish is won or lost in these 25 miles.
The altitude adjustment: what your sea-level long runs are worth here¶
At Leadville's base elevation of 10,200 feet, and higher still on Hope Pass at 12,600 feet, unacclimatized runners arriving from sea level typically see a 12 to 18 percent pace reduction relative to their sea-level aerobic effort. That is not a penalty. It is a variable, and a predictable one.
A runner whose comfortable ultra long-run pace at sea level sits around 18:00 per mile will run closer to 20:10 to 21:14 per mile at Leadville's base elevation, and slower still during the Hope Pass crossings.
Here is the practical translation for your own numbers:
| Sea-level long-run pace | Best case at altitude (+12%) | Conservative at altitude (+18%) |
|---|---|---|
| 13:00/mi | 14:34/mi | 15:20/mi |
| 14:00/mi | 15:41/mi | 16:32/mi |
| 15:00/mi | 16:48/mi | 17:42/mi |
| 16:00/mi | 17:55/mi | 18:53/mi |
Take your own long-run average pace from the past six weeks, find it in that range, and read across. The two numbers are your bracket. The Winfield cutoff requires averaging under 16:52/mi from the gun. A target arrival at 5:15 PM (with buffer) requires averaging under roughly 15:58/mi.
Check whether your altitude-adjusted bracket sits above or below those lines. That is your real buffer calculation.
For a deeper look at the acclimatization side of this, including arrival timing and altitude physiology, the ultra altitude racing post covers that ground in full. This post is focused on the pace math only.
Running the numbers: a self-check against your last six weeks¶
Training is done. There is nothing left to add to the fitness. What is worth doing now, in taper, is reading your training data honestly against the cutoff math. Three questions:
1. What is your time on feet across your three longest training runs?
Not miles. Hours. How many total hours have you spent moving at ultra effort on your longest days? The cutoff math runs on time, not mileage. Winfield closes at 14 hours. Twin Lakes inbound at 18 hours 15 minutes. If your longest training block is 10 to 12 hours and you have not done back-to-back long efforts, your legs and your stomach have not been asked to keep working past that threshold. That is worth knowing before the gun.
2. What is your pace on varied terrain in the past six weeks?
Pull the average pace from your longest runs on hilly or trail terrain. Not road pace from a flat route. Apply the 12 to 18 percent altitude adjustment using the table above. Does the adjusted number, at the conservative end, still land under your target arrival pace for Winfield?
If yes, the math supports your plan. If the conservative estimate puts you above that line, that is information. It does not mean you do not finish. It means you should build your crew callout plan, your Winfield arrival estimate, and your buffer targets around the adjusted numbers rather than your sea-level training pace.
3. What does your time-on-feet picture look like past 20 hours?
Leadville requires up to 30 hours of continuous movement. Some runners have only ever trained to 10 or 12 hours, and they finish. But those runners also report that the night section, roughly hours 14 through 26, is qualitatively different from anything in their training log. If your longest effort sits well under 20 hours, the question is not fitness. It is whether your stomach, your mental state, and your ability to keep eating past midnight have been tested at all.
Time on feet is the honest measure here. Mileage does not tell you this. Your training log does, if you read it for hours rather than miles.
The Winfield buffer: why most runners who miss the finish miss it here first¶
The Winfield cutoff is at 6:00 PM. The typical DNF story does not start at 5:58 PM. It starts at the base of Hope Pass on the outbound journey, where runners who were on plan discover that the climb cost more time than they had budgeted.
Hope Pass outbound rises from roughly 9,000 feet at the base to 12,600 feet at the summit over approximately 4 to 5 miles of steep trail. Most runners power hike a significant portion. Most runners are also slower on that section than they expect, because the combination of miles already banked, altitude, and the grade is harder than any training simulation available at sea level.
Here is the structural risk: a runner who arrives at Winfield at 5:50 PM, ten minutes before the cutoff, is not behind because they ran a bad 50 miles. They are behind because they did not budget the Hope Pass cost. And now they have 4 hours 15 minutes for the return, which includes going back over Hope Pass at night. That math is extremely tight.
Arriving at Winfield with 60 minutes of buffer before 6:00 PM means arriving at 5:00 PM, 13 hours elapsed, roughly 15:41/mi average from the gun. That buffer is not padding. It is the cost of the return crossing.
What the 30-hour finish actually looks like, segment by segment¶
This is one shape of a 29-hour finish, with arrival targets and buffer at each major station. The segment paces are approximate and will vary with terrain, crew transitions, and how your body is actually moving that day.
| Waypoint | Mile | Target arrival | Elapsed | Cutoff | Buffer | Segment pace |
|---|---|---|---|---|---|---|
| Start | 0 | 4:00 AM | 0:00 | n/a | n/a | n/a |
| Hope Pass summit (outbound) | ~43 | ~3:30 PM | ~11:30 | none | n/a | ~16:00/mi |
| Winfield | 49.8 | 5:15 PM | 13:15 | 6:00 PM | 45 min | ~15:30/mi |
| Twin Lakes, inbound | 61.8 | 9:30 PM | 17:30 | 10:15 PM | 45 min | ~21:15/mi |
| Mayqueen, inbound | 87.2 | 5:00 AM | 25:00 | 6:30 AM | 90 min | ~17:43/mi |
| Finish | 99.7 | 9:00 AM | 29:00 | 10:00 AM | 60 min | ~19:12/mi |
The column to compare against your training data is the elapsed time column, not the clock time. At 11:30 hours, where have your long runs typically found you? At 17:30 hours, how is your stomach doing? At 25:00 hours, have you ever been moving at all?
The segment pace from Winfield to Twin Lakes inbound (21:15/mi for 12 miles) is the one that surprises most runners on paper. That is a 29-hour-finish runner crossing Hope Pass at night for the second time. At sea level on flat ground, 21 minutes per mile is a deliberate walk with occasional jog. At 12,000 feet in the dark on rocky trail after 50 miles, it is the pace required to stay in the race.
Three weeks out: the only number that still matters¶
Training is done. The fitness in your legs right now is the fitness you will carry to the start line. This is not the moment to add a final long run or squeeze in a hard effort.
What it is the time for is reading your data honestly. If you have been logging your runs, your training log already has the picture. The time on feet across your longest days, the pace data from trail runs, the effort distribution across a 10- or 15- or 20-hour block. That data maps onto the cutoff chart in ways that are worth seeing clearly before the gun goes off.
Four weeks is also enough time to adjust your crew callout plan, your buffer targets at each station, and your mental model of the race. If your adjusted pace numbers suggest you will be arriving at Winfield with 30 minutes of buffer rather than 60, your crew knows that now. Your pacer knows that. You know that. That is not a problem. It is a plan.
The math is not a verdict. It is information. You get to decide what it means.
If your training is logged in Strava, NavRun can pull the time-on-feet picture across your recent training block and show you how your long runs map against the cutoff windows. It is not a prediction. It is your own data, laid out clearly.
For the altitude physiology behind the 12 to 18 percent reduction, including acclimatization timing and what to do in the days before the race, the ultra altitude racing post goes deeper.
See you at the finish on August 22.