The general classification (GC) contenders will face their first important test in Thursday’s sixth stage, which ends at the top of the Planche des Belles Filles after a punishing seven kilometres effort with an average gradient of 8.7 per cent.
There can be no hiding and all eyes will be on defending champion Thomas, who was caught at the wrong end of a split in the brutal, albeit brief, uphill drag at the end of the third stage.
“It was nothing, it doesn’t change anything,” Brailsford told reporters after Tuesday’s fourth stage, which went smoothly for the whole Ineos team.
But Thomas has not raced in the mountains since the Tour de Romandie in early May as he withdrew from the Tour de Suisse following a crash before the race hit the mountains.
“The lads got a lot of mountain training, he’s not been sitting on his arse,” said Brailsford.
“The Giro lasted 90-something hours and the guys trained for 118, they trained hard, these lads.”
With their rivals sensing possible weaknesses in the British outfit in the absence of four-time champion Chris Froome, Thomas and team-mate Egan Bernal, the main favourites this year, will be keen to make a statement at La Planche des Belles Filles.
“It’s very steep in the end and there will be differences,” said Brailsford. “Maybe not a lot between the bests but if someone has a bad day they will pay for it.”
Among Ineos’s rivals is France’s Thibaut Pinot, who lives in the region and knows the climb inside out.
He finished second there in the 2014 Tour, in which he ended up third overall, and Brailsford is wary of the menace.
After a solid team time trial showing with Groupama-FDJ, Pinot is 12 seconds off Colombian Bernal and seven behind Thomas.
“He’s done a good time trial,” said Brailsford. “He could win the race overall, who knows, he was third in 2014. He looks in great shape, he looks sharp, I’d say.”
It is however too soon to accurately assess the GC contenders’ form.
“You’ve got to wait to see. You’re going to get little glimpses if you like, but nothing significant,” added Brailsford.