GENT, Belgium (VN) — There will be a moment Sunday when the elastic snaps and Paris-Roubaix dramatically transforms into a gripping battle between a select few.

The rigors of the unending sectors of cobblestones, and the chaos caused by crashes, punctures, and mechanicals, will have taken their toll. But it’s more than the treacherous stones that make Paris-Roubaix one of cycling’s most enthralling events.

There’s also the distance. At 257km, Sunday’s Roubaix is a hard-man’s race in every sense of the word. In fact, before that decisive moment when the race comes down to the few, there will be another moment: Usually around the Carrefour de l’Arbre, Roubaix reaches another breaking point. Deep in that final hour is when Roubaix’s magical moments unfold on cycling’s most punishing canvas. The strong distance the weak.

“That’s why the monuments are always won by big riders,” said Patxi Vila, an ex-pro and trainer of three-time world champion Peter Sagan. “You hit that wall after five hours of racing. After that, a new race starts. That is the big difference between a great rider and a good rider at the monument distance.”

On Sunday, there will be scores of riders who believe they can go that distance to win Paris-Roubaix. The reality is that barely a dozen of them have the engine to endure the monument distance and still have the legs to win after six hours of racing.

Only Silvan Dillier (Ag2r-La Mondiale) was be able to stay with Peter Sagan at the 2018 Paris-Roubaix. Photo: Tim De Waele | Getty Images

Cycling’s five monuments — Milano-Sanremo, Tour of Flanders, Paris-Roubaix, Liège-Bastogne-Liège, and Il Lombardia — are cycling’s longest, oldest, and most prestigious races. All stretch to around 250km and last about six hours. The only other race that packs such heft is the road world cycling championships.

It’s the longer distance coupled with the all-in, nothing-to-lose mentality that sets the monuments apart from any of the other races on the international calendar. If a rider cannot go the distance of the monuments, they have no chance at victory.

“You can see there is a barrier,” said ex-pro Dirk Demol, who won Paris-Roubaix in the longest breakaway in the race’s history. “You might feel fine to 200km, but after that, there are only a few who can go the distance and be a winner. There are super-good riders who can dominate and make good results at 200km, but if the race is longer, they disappear.”

Sunday’s Roubaix boasts international renown for its rough cobblestones, but all the monuments have the longer distances in common. Lombardia might be shorter (last year’s edition was 241km), but it features more climbing. Liège is just under 260km, while Flanders is just over 270km.

Even at a race as relatively “easy” as Milano-Sanremo, pros will say they feel the sting of nearly 300km of racing in their legs when they hit the Poggio and again when they launch a finishing sprint down the Via Roma.

The extended length of the monuments creates a natural selection within the peloton that is unseen in other races. It’s the cycling equivalent of hitting the wall in a marathon, or to mountain climbing’s “death zone,” but without the accompanying dangers. It’s a distance that creates a clear separation within the peloton.

“If you have 30 riders who can win a race of 200km, and you compare that to a race of monument distance of 260km, it is just a handful of riders,” said ex-pro Erik Zabel, now performance director at Katusha-Alpecin.

Greg Van Avermaet led the chase at the 2019 Tour of Flanders. Photo: Tim de Waele/Getty Images

Certain riders thrive on the pain and distance of the monuments. CCC Team’s Greg Van Avermaet knows his chances of victory vastly improve with each passing kilometer. A hard race jettisons faster riders who are marking wheels and saving themselves for a sprint.

“That extra 50km of racing is what really sets the monuments apart,” said CCC Team rider Michael Schar. “The harder and longer it is, the better it gets for Greg. And when it is that long, you don’t need as much support. At the end of the big races, they are quite isolated. When it’s man against man, when it’s old-school racing, that’s his kind of style. That’s what he likes, and when he does the best.”

So what does that extra hour of racing feel like? EF Education First sport director Andreas Klier described it like this:

“It’s like if you go cycling with a pro,” he said. “You might feel pretty good for the first 80km. But by 160-190km, you wish you would not have done that. It’s a question of your capacity and the training you’ve done, and with what talent you were born with.”

Mat Hayman, winner of the 2016 edition of Roubaix, said the longer monuments generally tend to favor veteran riders. Younger cyclists can win, of course, but he said the capacity to put out the power to race six hours is built slowly over time. Hayman, who won Roubaix at 37, says that’s why many riders are still capable of winning Roubaix relatively late in their careers.

“After 200km, you do see that extra bit of cream rise, and the older and more experienced riders come to the fore,” Hayman said. “Some guys really struggle with the 6.5-hour classic. It’s a maturity thing. You come from the amateurs and there’s a lot to learn. If you come from the amateurs, you’re doing 180km, and then all of a sudden 260km — that’s a big jump. You find the older guys are able to do it. It’s about managing your energy to be good at the right time of the race. And that takes time.”

Four-time Milano-Sanremo winner Zabel has an interesting take on the monuments. He said recent trends in training and preparation have pushed toward high-intensity efforts to produce bigger power for accelerations on climbs and sprints. Zabel is a firm believer that the old-school style of training, loaded with base miles, still has its place in modern cycling, especially for riders who want to shine in the northern classics.

“I still believe it has something to do with experience and distance training,” Zabel said. “All these coaches from universities who have come into cycling, they are working with high-intensity training, and that makes the riders strong in a distance up to 200km. The real distance is after 250km. The big riders want to build their base for the classics. After [Three Days of] De Panne, you see them behind the cars riding home after a 200km race, and then go that distance of 250-260km. It is not only about talent and experience, it is also about work.”

Nobody wanted to take up the sprint in the velodrome at the 2016 Paris-Roubaix, but Mat Hayman found himself on the front with 200 meters to go. Tom Boonen and Ian Stannard looked well-positioned to come around him before the line, but the Aussie veteran was just too strong. Photo: Tim De Waele / Getty Images

As the peloton continues to modernize, physiologists have incorporated training techniques from other aspects of cycling to help prepare riders for the classics. Team Sky was among the first to put a renewed emphasis on altitude training camps a decade ago, bringing its classics riders to such places as the Teide volcano on the Canary Islands. Though Sky has yet to win Flanders or Roubaix, other teams have embraced some of those same training methods.

Bora-Hansgrohe’s Peter Sagan, already a winner of both Flanders and Roubaix, has recently incorporated altitude training in Spain’s Sierra Nevada to his regimen to prepare for the spring classics. Anything that helps endure a monument is seen as a plus.

“In a race that is more than six hours, it’s about arriving as fresh as possible,” Vila said. “It’s a real endurance race more than anything else. We focus a lot on the long endurance and we’re always looking for that efficiency. So it’s about saving energy during the whole race, and saving some energy that your adversaries have not.”

There has been some suggestion that race distances should be reduced, especially in stage racing, based on the argument that a race is more exciting if it’s all packed into three or four hours of intense effort.

What might work in the Vuelta a España won’t fly in Belgium. So far, the monuments are defying that trend and sticking firmly to their long-distance roots. The longer the better for the old-school cobble-bashers in the bunch.

“I only have a chance when the race is really hard,” said Alexander Kristoff (UAE-Emirates), winner of Sanremo and Flanders. “If I can be there in the finish after 250km, I know I have a chance. The long races mean there are only a few riders who can go that far. That’s better for me.”

If Kristoff can be there in the final hour Sunday, it’s likely he won’t have much company. The monument distance always takes its toll.