Mercedes have explained why they were tempted to try the Medium tyre for the final stint of the United States Grand Prix, in a bid to catch Max Verstappen.
Lewis Hamilton was fitted with the Hard tyre for the final stint of the race, pitting at the end of Lap 37 of 56. This was a full eight laps after Verstappen had pitted for the same compound and, given the much smaller distance to the chequered flag, Mediums appeared to be the logical choice as Hamilton pursued the Red Bull.
But, instead, Mercedes opted for the Hard tyre again. Speaking after the United States Grand Prix, the team's Head of Strategy, James Vowles, outlined why that decision had been made.
"All the way through the race we are continuously building up tyre models," he said in the team's official race debrief.
"We have an understanding of how they are all performing to each other, the Soft, the Medium, the Hard. Not just from ourselves but from our competitors as well.
"What was very clear is that the Medium was a very poor tyre for us. On that first stint of the race, we were quite slow. I would say probably in the region of over half a second off what we could do on the Hard. And that became an easy decision for ourselves.
"I think it would have been more difficult with other cars, but given our situation, and given that we know that we were poor in stint one of the race, it wasn't an option to fit the Medium again.
"The degradation would have been too high and Lewis, whilst [he] would have still caught Verstappen, wouldn't have had the tyre to even have a go at the end."
Another option that had appeared to be a possibility was a one-stop strategy, which has been a viable plan at the Circuit of the Americas in previous years. But Vowles stated that such a gamble was simply not an option in 2021, due to the abrasiveness of the track surface and the relative life of the tyres.
"Not on the tyre lives that we had this year, no," he said when asked about the strategy option.
"There are a few concepts that allow you to hopefully see that. If we go back to 2019, a year where it wasn't as warm, where we didn't have as much degradation on the tyres, Lewis just about did a one-stop race with a car that was fast.
"If you remember, [in] the dying stages of the race, he had run out of tyres and [was] struggling relative to Verstappen behind, who was going to overtake him.
"Now, that was an on the limit one-stop. This year, the track was warmer, the track has evolved, it's more aggressive on the tyres, there was a lot more degradation, so even just taking those into account you can see how a two would be the fastest strategy and a one just not even possible.
"To put it more into context, a three would have been a much better strategy than a one-stop here in Austin this year, given what we had on tyre degradation.
"Long story short, no, a one-stop wasn't on the cards, wasn't possible."
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