Thomas currently leads teammate and defending champion Chris Froome by 1:39, with Tom Dumoulin (Team Sunweb) a further 11 seconds in arrears. Stage 17 may only be 65km in length, but with the Col de Peyresourde, followed by the Montee de Peyragudes, Col de Val Louron-Azet and final ascent of the Col de Portet – which was freshly asphalted ahead of the race – is arguably the toughest climb of this year's Tour. Add into the mix ASO's new grid formation start, with GC leaders starting at the front of the race, and we could have one of the most dramatic days of racing in recent memory.
"I think that it's going to be massively decisive and we're going to see some big gaps," warned Thomas in his post-stage press conference in Luchon after coming through a late Movistar assault near the finish of stage 16.
"It's the first time that we've done anything like that, and I think that it's going to be about two hours of climbing, which is a lot over such a short period of time. Maybe that's why we didn't see that many attacks today. Everyone is a bit apprehensive about it. You can't get carried away because that final climb is possibly the toughest climb of the Tour. It's going to be a big day and for sure there are doing to be some splits."
Given that there is no blueprint for stage 17 and the history books have seen nothing like a grid system combined with such a short and brutal stage, the tactic books that teams will use are effectively blank. There is one assumption that Thomas and Froome will simply attack and ride a two-up time trial to the finish. Given what we saw from Froome on the Finestre stage of the Giro d'Italia nothing can be ruled out, but as Team Sky's strength is their depth, a more likely scenario would involve one and two on GC waiting for their teammates, who will start just a few meters down the road.
It's the riders further down in the standings, such as those from Movistar and AG2R, who have a greater chance of trying their luck. Both teams have looked to put Team Sky under pressure in this year's race, but bar the odd moment they've come up relatively short. Neither team has a winner of the Tour in their ranks unless they throw caution to the wind and Team Sky are either complacent or have a collective bad day. Dumoulin and Primoz Roglic (LottoNL-Jumbo) will be watched likes hawks, while their time trialing skills could see them try and stretch the yellow jersey.
At the finish in Luchon, seventh-placed rider Steven Kruijswijk (LottoNL-Jumbo) told Cyclingnews that the grid start was effectively a gimmick and would not alter the race. In his mind, Team Sky would assume control of the race over the first two climbs before putting the hammer down on the final ascent.
Thomas predicted that a handful of GC riders could try an early move but also added that the majority, if given the choice, would stick together at the start.
"There will be some attacks but I'm not so sure that the grid start will affect the race so much. Obviously, if some of the guys in the top 10 go it will be a gutsy move, and there are a few guys you'd expect to go more than others but to go from the start would be risky for sure. We'll just to need to ride it together."
Race neutralization and pepper spray
Froome came through stage 16 unscathed and briefly chased Mikel Landa (Movistar) when the Spaniard attacked on the final climb. The stage was marked by a farmers' protest in the early kilometres, and the authorities used force and pepper spray to clear a path for the Tour convoy after demonstrators pushed hay bales into the road. The decision to use pepper spray backfired, with riders caught downwind of the fumes. Thomas and Froome were among those affected by the spray.
"I could feel it in my eyes and a bit of a tingle in the back of my throat. I had some water and rinsed my eyes out, and washed my mouth out. I was lucky that it didn't affect me too much," said Thomas.
"I just sprayed some water in the eyes and water in the face," added Froome.
"My throat, nose and eyes were burning afterwards, but I think quite a lot of riders were in a similar situation so I think we were all grateful for the temporary neutralisation just to have a couple of kilometres to clear our eyes, nose and throat out and then the race continued again. Thankfully the effects didn't last long. Temporarily everything was stinging and burning but it wore off pretty quickly."