It is the Fourth of July in New York City, and that can mean only one thing. No, not fireworks, sweaty subway rides and family cookouts. It is time for the Nathan’s Famous Hot Dog Eating Contest in Coney Island.

The contest has long been a holiday mainstay in New York, and must-see midday TV across the country. But this year’s event, which tests “competitive eaters” on how many hot dogs they can frantically scarf down in 10 minutes, promises to be unusually suspenseful.

For the first time in almost a generation, the men’s competition has no clear front-runner.

Joey Chestnut, the 16-time champion, was forced to part ways with the contest last month after he signed an endorsement deal with Impossible Foods, a rival to Nathan’s that makes vegan hot dogs.

Many viewers tuned in year after year just to watch Mr. Chestnut go through a pile of hot dogs like a wood chipper. News of his departure from the contest was met with the sort of public anguish one might expect for a major-league baseball player, not a man who ate 62 hot dogs in 10 minutes last July 4.

Even Senator Chuck Schumer, a Brooklyn native, mourned what he called “‘impossibly’ hard-to-swallow news.”

In an interview last month, George Shea, the charismatic showman who helped elevate this whole spectacle into the sort of event that is covered by The New York Times, said he was “devastated” by the situation.

He said Mr. Chestnut’s endorsement deal had left Major League Eating, which bills itself as “the governing body of all stomach-centric sport,” with no choice but to bar him.

“It would be like back in the day Michael Jordan coming to Nike, who made his Air Jordans, and saying, ‘I am just going to rep Adidas too,’” Mr. Shea said. “It just can’t happen.”

But the split also “opens up the entire contest for new champions,” he said. Their efforts will be broadcast around the world — the contest seems particularly popular in Asia — and shown live in the United States on ESPN2 and ESPN3. It will re-air on ESPN twice on Thursday night.

The men’s competition kicks off at 11 a.m. outside Nathan’s Famous, the Coney Island stand that spawned a hot dog empire. The women’s competition begins at noon.

On Wednesday, those aspiring champions gathered in Midtown for the contest’s official weigh-in ceremony. (The contest does not separate eaters into weight classes, so it was not clear why anyone needed to be weighed.)

Among those lining up for a chance to replace Mr. Chestnut were five men, some of whom had traveled from as far as Brazil, Australia and the Czech Republic. (“I eat dumplings,” said Radim Dvoracek, 33, the Czech competitor. “Hot dogs are hard for me.”)

On the women’s side, the competition is dominated by Miki Sudo, 38, the nine-time women’s champion, who ate 39.5 hot dogs in 10 minutes last year. Other women traveled from places like Japan and South Korea to challenge her.

The favorite to succeed Mr. Chestnut as the men’s champion appears to be James Webb, 35, a former professional soccer player from Australia.

He began competitive eating “as a joke,” he said in an interview, and is now a full-time content creator on social media, where he posts food videos.

Mr. Shea described him as “the No. 1 eater in the Southern Hemisphere” and the fifth ranked competitive eater in the world. (The Southern Hemisphere holds only about 10 percent of the world’s population.)

Mr. Webb appeared delighted to be in New York, and said he hoped to someday have an eating career like Mr. Chestnut’s.

“Joey set standards that all of us are trying to beat,” he said. “Joey is like the Terminator.”

The hot dog eating contest is the sort of absurd public event for which New York City has long been known. Over the years it has developed its own lore, canon and epic heroes, of whom Mr. Chestnut was long the king.

According to outer-borough legend, the contest has been held each year since 1916, when Nathan Handwerker opened a hot dog joint on the corner of Surf and Stillwell Avenues in Coney Island.

But like many legends, this one is mostly myth. The contest actually began in the early 1970s, and in 2010, one of its original promoters, Mortimer Matz, admitted that he had cooked up the origin story in “Coney Island pitchman style.”

In recent years, the event has been powered largely by the wiener puns and theatrical patriotism of Mr. Shea, who calls it “a celebration of freedom,” and by the star power of Mr. Chestnut.

The contest made him famous, and he in turn became synonymous with the event — which means his specter looms over the proceedings this year. As the weigh-in ceremony began on Wednesday, Mr. Shea repeated the tale of Mr. Chestnut’s departure for the crowd, before reassuring them that he would be welcome to return to the Coney Island event at any time.

Mr. Shea then introduced the first women’s competitor, Elizabeth Salgado, 32, by noting that she was from Vallejo, Calif., “the original home of Joey Chestnut.” (Ms. Salgado said her hot dog goal was “to eat as many as I can, just to beat my sister.”)

Representatives for Mr. Chestnut did not respond to a request for comment.

For those who still wish to watch Mr. Chestnut eat an unsettling number of hot dogs on July 4, he will travel to Fort Bliss, in El Paso, to compete against soldiers in a five-minute hot dog eating contest, according to The Associated Press.

He will also headline a hot dog eating contest on Labor Day that will stream live on Netflix, along with Takeru Kobayashi, another former July 4 hot dog champion who was ejected from the Coney Island contest in 2010 after a falling out with Major League Eating.

Mr. Chestnut’s trajectory may have taken him out of the Nathan’s competition — for now, at least — but Mr. Webb said on Wednesday that some version of his celebrity status is what everyone in the contest hoped to achieve.

That is why they spend the year training, eating and stretching their stomachs. (His method involves using a foam roller on his abdomen followed by a trip to a buffet, he said.)

“We are all weird,” said Mr. Webb, as a person in a giant hot dog costume danced nearby for TV cameras lined up beneath the Vessel in Hudson Yards. “We are all weird in our way. But we are hella competitive and pretty disciplined. And that’s kind of the part people don’t see.”