There’s a lot to be excited about for this weekend’s Chicago Marathon.

John Korir will look to defend his title and solidify his case for the top male marathoner in the world. 14:12 5000m runner Ejgayehu Taye will make her marathon debut, and an Ethiopian sweep looks very likely as all four of the sub-2:20 entrants are her countrywomen. Natosha Rogers, Dakotah Popehn, and Gabi Rooker will battle for top American honors.

All those plotlines, while exciting, are going to take a backseat—because 28-year-old Utahn Conner Mantz has made his intentions clear: the American record or bust.

Which American record, you might ask? Mantz probably has two different marks sticky-noted to his vision board. The official mark is Khalid Khannouchi’s 2:05:38 from the 2002 London Marathon, which was also the world record at the time. But the fastest an American has ever run for 26.2 miles is Ryan Hall’s 2011 2:04:58 showing in Boston, where he benefited from a hefty tailwind on the point-to-point course.

Mantz is coming off a strong run of his own in Boston, where he ran 2:05:08 to finish fourth in the second-fastest all-conditions performance by an American. That run, which came three months after Mantz broke Hall’s national record in the half marathon, would suggest that both the official and unofficial marks are within reach for Mantz.

But just because 10 seconds looks like a tiny gap on paper doesn’t mean it won’t feel huge out there on the course. Can Mantz get it done? The answer to that question depends on at least three major factors: Mantz’s own ability, the field of runners around him, and the dynamics of raceday.

Let’s start with the man(tz) himself. The Ed Eyestone-guided BYU alum is coming off recent wins at the Beach to Beacon 10k and the U.S. 20K champs. In 2023, Mantz did the same double before his 2:07:47 run in Chicago, running 27:58 and then 59:16. This time around, he ran 27:26 and 56:16. Obviously, race conditions can vary year to year but it’s a promising sign.

Plus, Mantz has rarely run a dud marathon. In seven attempts, his worst performance was an 11th-place, 2:10:25 finish at Boston in 2023. This year in Boston, he finished fourth against a respectable field. He may have to improve on that finish in Chicago to run the requisite time, though. Fourth place in Chicago has recently taken a 2:05ish effort. 2024’s fourth placer ran 2:05:09; 2023’s ran 2:05:16, and 2021-2022 were a bit slower. Sub-2:05 made the podium each of the last two years and in 2022, third place was 2:05:01… run by John Korir. So basically, aiming for a top-three finish and the American record in Chicago are one and the same goal.

The men’s elite field is pretty deep this year, with nine entrants under 2:05 and six under 2:04, including Ugandan Jacob Kiplimo. He’s the world record holder in the half marathon at 56:42 (no, that’s not a typo), and coming off a 2:03:37 debut for second place at this year’s London Marathon. Unlike Boston, Chicago allows pacers to help share the load over the first part of the race, and Mantz is slated to have his own designated rabbit, but will the rest of the field be useful to Mantz?

Kiplimo, along with Korir (2:02:44 PB) and Timothy Kiplagat (2:02:55 PB) will likely be right on the heels of the pacers. If these three want to cook (remember that the late Kelvin Kiptum’s 2:00:35 was run on this course), the leaders will likely hit halfway in something blistering. How fast is the critical question: If the leaders are on 2:01 pace, Mantz would hopefully be wise enough to let them go and run his own race. With the depth of the competition, there should be a group that can hang together around 2:04-2:05 with or without a designated pacer.

The trickier circumstance arises if the leaders are a tad slower—say, 61:30 at halfway—and there’s a big, tantalizing pack up front. If Mantz (or anyone else with top-five aspirations) gets out ahead of his skis in an attempt to stick to the early leaders, those 30 seconds could prove quite costly in the back half. That said, Korir won both Chicago and Boston by virtue of a blistering second half, so he may want to keep things conservative early as well. Last year, the leaders hit halfway in 62:19 before Korir seized the front around 30K. If he employs a similar strategy, that would work out perfectly for Mantz’s purposes.

Prevailing wisdom is that Boston runs a bit slower than Chicago. But weather conditions were close to ideal for Boston this year, with no major headwinds and temperatures under 60 degrees for most of the race. Right now, it looks like wind won’t be an issue in Chicago, but the heat could be. The race kicks off at 7:30am and the overnight low is predicted to be 53º, but the forecast calls for a high of 74º with 57% humidity.

In 2021, temperatures around 70º and oppressive humidity slowed times across the board. Seifu Tura and Ruth Chepngetich (lol) won in 2:06:12 and 2:22:31. Unless something changes drastically, this year’s edition shouldn’t be as challenging, but the forecast is borderline enough that Mantz-heads and casual Chicago-goers alike will be nervously refreshing their weather apps for the next few days in hopes of a break for the better.

So can Conner Mantz break the American record on Sunday? Absolutely. Will he get the job done? Only one way to find out! Either way, watching him try as the seconds and miles tick by will likely be the most thrilling part of this weekend.

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