Ypres (Belgium) (AFP) - Race leader Vincenzo Nibali and other riders will be using specially modified bikes for Wednesday's cobbled fifth stage of the Tour de France.
Nine sections totalling 15.4km of cobblestones along the 155.5km route from Ypres in Belgium to Arenberg have turned the stage into a mini Paris-Roubaix.
It has had riders and spectators alike excited since the Tour route was announced last September.
But as the cobbles provide a distinctly different surface to ride on, each team will roll out slightly different equipment more suited to the bumps.
Nibali has already ridden the stage in preparation.
"More than anything my intention was to find out what material, wheels, etc, I needed to use," he said.
"I'm talking about the technical material of the bike, so we'll change the bike.
"I've never done Paris-Roubaix, so it will be new for me.
"Tomorrow it's predicted to rain. We hope it won't because this can complicate everything."
One crucial element is having the right bike and at Trek, three-time Paris-Roubaix winner Fabian Cancellara played a leading role in designing a bike specifically for the cobbles.
"That bike is a little bit different in that it's longer. In Roubaix you have to go in straight lines and to steer the bike as little as possible, so by making a bike longer it's more stable that way," said Trek mechanic Jordan Ressingh.
- Vertical compliance -
"It also has clearance for larger tyres. Typically for a stage we use 22mm or 24mm tyres but for Roubaix we use 27mm tyres.
"In order to use bigger tyres like that we need to have clearance underneath the brakes, so the frame provides that clearance."
At Cannondale they developed a bike that changes the position of the rider to a slightly less aerodynamic one.
"We build in some added features for a little bit more vertical compliance for those rougher days in the saddle," said head of marketing Jonathan Geran.
"To get more comfort we sit the bike a hair more upright.
"That athletic ready position as they're going over cobbles, as they're encountering more bumps in the road that are rougher and that are going to jar them and jar their hands around, that slightly more face up position will keep them more comfortable and keep them more ready."
Above all, the cobbles must be respected and cannot be underestimated.
The last time the Tour passed through Paris-Roubaix's most notorious territory in 2010 it claimed several victims.
Luxemburger Frank Schleck, brother of Andy who won the Tour that year, broke his collarbone in a crash on the cobbles.
Frenchman Sylvain Chavanel, a Classics specialist, went into the cobbles wearing the yellow jersey but lost it after falling once and suffering two punctures.
As much as the cobbles themselves and the potential for falling or puncturing pose problems, the biggest fear factor comes from the weather, according to Team Sky's Geraint Thomas.
"It's going to be a nightmare, no-one's looking forward to it, especially if it rains," he said.
"It's just going to be like riding on ice, especially with some of the corners on the cobbles. It will be last man standing I think."
Thomas will have a doubly difficult day as not only will he be trying to keep himself upright, but he will also be charged with protecting team leader and defending champion Chris Froome.
Thomas finished seventh at Paris-Roubaix in April so he knows the cobbles well and he will be the man charged with keeping Froome out of trouble.
But having fallen and hurt his wrist in Tuesday's stage, necessitating the wearing of a splint to protect it throughout the rest of that stage, Froome is hardly in tip-top shape.