Team FDJ general manager Marc Madiot went on the attack for the material Sky used in their riders' skin suits in Saturday's time trial, which was won by Geraint Thomas and finished with three others Sky riders, including Chris Froome, in the top-10.
The controversy kicked off with Madiot's comments and complaint to the UCI jury on Saturday, but Sky used the Castelli "TT Suit 4.0" kit in the Giro d'Italia time trial – where Thomas finished second after crashing two days beforehand – and in the Critérium du Dauphiné.
"For me, it's quite funny," Brailsford told Cycling Weekly.
"We do our competitive analysis. If anything changes in the WorldTour peloton, I know within 24 hours. And all of a sudden they discover it on the first day of the Tour?
"Come on guys, what are you doing? Either you are doing your job properly or you are not. Either they didn't see at the time or they saw it at the time and didn't raise it, or they just saw it.
"And if they are just seeing it now then what are they doing? Focus on your own team, maybe they need a skinsuit."
Madiot would not comment on it this morning when approached and said to speak with the UCI. The UCI's race jury head on the ground, Philip Marien, said he would not comment on it.
FDJ's performance expert Frederic Grappe told the AFP news agency that the vortex air pellets in the fabric would save Sky 18 to 25 seconds over the 14-kilometre stage one in Düsseldorf.
"It's insane, most people who know about skinsuits know that's just not feasible," Brailsford said of the time advantage claims. "I don't know what wind tunnel they use. If they think they can find those gains then that's pretty something."
Sky, just like with their bikes, has clothing approved by the UCI. Other teams too have had similar developments approved too, with Movistar using a similar specifically added material for time trials and on its road jersey.
Marien told RTBF: "We called the team to speak after the stage. We examined the skinsuit and its [vortex material] integrated into the fabric, it's not really a violation of the UCI rule. We have no way of forbidding it."
The new white jerseys rolled out for the Tour made the material more noticeable than the black jerseys Sky used to use.
Sky came under fire in the past for certain "marginal gains" like bringing a camper to Giro d'Italia for Richie Porte to use. The UCI outlawed the camper, saying riders must sleep in the hotels arranged by the organiser.
French newspaper L'Equipe ran a front page story on Monday that could sway public opinion against Sky.
"EXCÈS DE VITESSE" or "Excessive Speed" it printed over a photograph of Froome. Inside, another article showed Geraint Thomas and a caption over the photograph, "Sky accusée de tricherie" or "Sky accused of cheating."
"I don't think it comes as anything new, we are used to it," Brailsford said of the newspaper headlines.
"It's fun. I'd say, we are very used to it. It's part of the fun of the Tour de France. We love the French. We do. We genuinely do. We love racing in France, love the French people, the French supporters and love the French race."
Thomas after stage two said: "At the end of the day, you can borrow the skinsuit if you want and see what time you do."
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