She pedaled a distance of 47.980 kilometers in one hour, USA Cycling confirmed. That's about 29.81339 miles.
Stevens set the record at the 7-11 Velodrome in Colorado Springs, Colorado. She rides for the Boels Dolmans Cycling Team.
She beat the previous record of 46.882 kilometers (29.13 miles) set on January 22 by Australian Bridie O'Donnell in Adelaide, Australia.
"It couldn't have been a more perfect day," Stevens said after her record ride. "Awesome."
For a time, the related hashtag #UCIHourRecord trended worldwide on Twitter, race announcers said.
Stevens' first coach, a former pro named Matthew Koschara, has not been surprised by her success.
He called her a "one in 10 million" talent.
"She has the right appetite, physiologically and psychologically," Koschara told Business Insider in 2014. "She's old school, she's hard core - she's a fighter."
He pointed to Stevens' remarkable power-to-weight ratio, and although he won't reveal stats from the time he coached Stevens, he says her three- and 10-minute power numbers, measured in watts, were "huge."
At five-foot-six and 120 pounds, she's compact and very powerful.
Well, that makes it official! #UCIHourRecord #RideWithHer pic.twitter.com/WmfrTsHnvr
"I would like to congratulate 'Evie' on her achievement," UCI President Brian Cookson added. "Bridie O'Donnell's record stood for five weeks and we have already seen two attempts this year despite only being in February,"
"Two years after the rule change, riders' interest in the UCI Hour Record has not waned," he added. "From Europe to North America via Oceania, one after another the athletes are pitting their strength against our sport's legendary event, in front of fans who can follow live their exploits on our YouTube channel."
The attempt
Stevens was all smiles when she entered the velodrome. She looked very at ease, and confident:
Her coach, Neal Henderson, is an expert when it comes to the hour record.
He and Stevens started training seriously in November.
Her trained a former world hour-record holder, Rohan Dennis of Australia.
Before the event started, she bowed her head for the national anthem:
Here was Stevens awaiting the start:
This is Stevens on the very first lap - after getting up to speed, she got set into her aero tuck:
This was the bike - made by California-based Specialized - that Stevens set the record on:
The velodrome she raced on is normally open air, but it was covered temporarily for this event.
It was built in 1983. It features a 333.3-meter (1,093.5-foot) banked track for cycling on a cement surface.
It's at about 6,000 feet above sea level and is climate-controlled.
This GIF below shows GoPro footage previously taken on the track.
Stevens used the footage to help her visualize her race as part of her training.
It all paid off: She broke the record handily, having raced at nearly 30 mph for one hour.
Evie Stevens: at one point halfway through I almost puked so I backed off a bit. #UCIHourRecord pic.twitter.com/6gIhEryni7
- Mary Topping (@butterflywriter) February 27, 2016
Officially 47.980 km for @evelyn_stevens #UCIHourRecord #RideWithHer pic.twitter.com/HLm3WZb7hB
- USA Cycling (@usacycling) February 27, 2016
From Wall Street to the open road
After graduating from Dartmouth in 2005, Stevens worked as an analyst for Lehman Brothers before taking a job as an associate at investment fund Gleacher Mezzanine (known today as Arrowhead).
Four hours' sleep a night. Seven-day workweeks. Diet Cokes around the clock. This was Stevens' life on Wall Street.
Years on, and far from Wall Street, Stevens now ranks among the world's best cyclists.
Stevens says she approaches cycling as she did investment banking: with tenacity. After turning pro, she dedicated herself completely - she was "hyper-focused" - just as when she'd started her business career.
"With investment banking and finance, it's not a world you gradually go into it," she said. "It's not like I started and they told me, 'Take your time, get comfortable, leave at 5 p.m.' You're on deals, you're operating on a high level quickly.
"If you want to get to that high level, you have to go after it," she said. "Investment banking is like pro cycling: It's not a career you have for 30 years. You realize, 'I'm going for it.' For my career in cycling, every day it's like, 'What do I need to do better? What do I need to train?' You can't become complacent."
At 32, she's in the prime of her career.
Even before setting the hour record on Saturday, she already had major victories crowding her palmarès, or race résumé.
Harry How/Getty Images
In late 2007, while on vacation in San Francisco, Stevens' sister talked her into doing a local cyclocross race, which at first seemed like a crazy idea.
She'd played tennis in college, went to the gym, and did some running.
But she rarely pedaled a bike, let alone raced one.
And yet there, in Golden Gate Park, at age 25, she raced for the first time, on a borrowed bike no less.
She crashed and got banged up, but she finished and was immediately hooked - "in love" even.
"I was like, 'This is awesome - this is for me,'" she told Business Insider last year about that first race.
She is also targeting the Olympics in Rio this summer.
"You don't know your limit until you hit it. I think I found it today."-@evelyn_stevens #UCIHourRecord
- John Bradley (@johnwbradley) February 27, 2016
"I've had some big wins, but I'm not at the top level yet. So it's like, 'What do I need to do to become top level?' I think it's the same in finance. For those moving up that ladder, they're constantly looking and thinking, 'How do you do it differently? How do you do it better?' It's a constantly moving process."
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