Every few years we cycling fans are treated to the sight of a grand tour contender bouncing his way over those treacherous cobblestones that seem to dot every inch of Belgium and northern France. I have tried to explain this devilish dynamic to my non-cycling friends, with limited success. My best analogy: GC guy on the pavé is akin to Tom Brady taking a few snaps at nose tackle.

In most instances, it’s a tough watch. Our spindly GC hero, so elegant in the high mountains, pedals squares alongside hapless domestiques within the peloton’s steerage. He grimaces. He grits. He clings to his bicycle as he skims over the incisor-rattling stones as if the rig might buck him off into the ditch.

For your reference, observe the above photo of Nairo Quintana riding E3 Harelbeke in 2015. His grimace says it all: I hate this.

As we all know, our grand tour heroes subject themselves to this torture not by choice, but out of necessity. At some point, in some distant boardroom, a cruel ASO executive decided to add a sector of two of ‘stones to the Tour de France route to, you know, really punch things up — maybe even boost the TV ratings by a point or two.

This decision sets our GC man up for a bummer of a spring break. He must now forego that warm training camp in the Canary Islands and instead board a flight to Belgium, where typical March conditions call for heavy rainfall and wafting clouds of manure. He must then bang elbows with brawny guys named Stijn or Jasper as he rattles along on the stones.

Our GC man must embrace the agony as a learning experience for July. After all, nobody wants to suffer the grim fate of Thibaut Pinot, Dan Martin, or Rafal Majka, all of whom flailed spectacularly on the stones at previous Tours.

As you have probably read, this year’s classics season marks a new chapter in this semi-annual rite. ASO has included a devilish section of cobbles on stage 9 of the Tour, and thus, multiple GC men are in Belgium this week to race on the stones. Mikel Landa raced E3 Harelbeke. Quintana, Alejandro Valverde, and Romain Bardet will compete in Wednesday’s Dwars Door Vlaanderen. And Vincenzo Nibali plans to race the Tour of Flanders this coming Sunday.

Should we expect Quintana or Bardet to actually win one of these races? Of course not. So how should we critique our GC men on the cobblestones? I’ve created a helpful scorecard:

Failure (F): OK, I’m setting the bar low here for our GC hero. If he crashes and injures himself, thus delaying his Tour de France prep or, worse yet, ending his season, well, that counts as an abject failure. Every scenario other than this should be considered success.

Passing (D): Our GC man battles for a few hours, is ultimately dropped, and records a DNF. His body, however, remains intact and he loses zero teeth. Think Quintana at the 2015 E3 Harelbeke, when he was dropped just 130km in and then abandoned.

Satisfactory (C): Our GC man shows glimmers of aptitude on the stones. Sure, he may eventually record a DNF due to the dynamics of the race and the time cut. But he rides alongside at least one Belgian strongman without ending up in the ditch.

Good (B): Our GC man finishes the race! He survives the entire 200-plus kilometer race and records a finishing time that is at least 20 minutes or so behind the race winner. Chapeau.

Excellent (A): Our GC man either factors into the final tactics of the race, or he finishes inside the top-20. Think Bradley Wiggins at the 2015 Paris-Roubaix. This scenario is proof that our GC hero is a bonafide stone eater. Watch out, Stijn.

Superior (A+): The GC guy wins the darned race. This scenario will not occur.

Mikel Landa already survived his test and scored a solid B at E3 Harelbeke. He was caught behind an early crash, fought back, and finished a respectable 86th place out of 95 finishers, 14 minutes down on winner Niki Terpstra. Great!

How will our other GC heroes fare? Here are my predictions. Quintana stays out of trouble, drops out early, and records a C. Fans are gifted an amazing image of him riding next to Stijn Vandenbergh.

Bardet earns a B. He rides that impressive Strade Bianche form and is impressive early. At some point, he reverts to self-preservation mode after 150km and rides in with the bunch.

What about Vincenzo Nibali, who is making his debut at Flanders? Nibali is capable of an A, however, my prediction is he records a B. Flanders is rarely kind to newcomers.

And then there’s Valverde, who races Wednesday at Dwars Door Vlaanderen. How will he finish? Your guess is as good as mine. The ageless wonder may actually win.