Mercedes has explained how concerns over graining and the available tyres are what prompted the team to split strategies twice in Formula 1’s Canadian Grand Prix.
The German squad’s renewed pace saw George Russell in contention to win from pole position during a thrilling mixed conditions race at the Circuit Gilles Villeneuve.
Once the track dried, Mercedes elected to put Russell on an alternative tyre choice with the Hard compound, while Lewis Hamilton behind was fitted with the Medium.
Mercedes Technical Director James Allison has described how the restricted dry running throughout practice due to intermittent showers created an obscure picture.
But with graining developing to be an evident issue in Montreal, Allison reveals how Mercedes thought the most durable rubber would be Russell’s best chance to win.
“The fact that we chose different tyres for the two different drivers was because it was not clear,” Allison said on the team’s Canadian GP review video.
“It absolutely was not. These things are clear afterwards, but not clear beforehand.
“When we ran on the Friday, the grid ran on the Friday with the Medium tyres, almost everybody in the pit lane grained the tyre.
“Once the tyre grains, it loses its performance very quickly and becomes an absolute sitting duck.
“The Hard tyre is more resistant to graining, maybe a little slower, but more resistant to graining. We fitted George with the Hard tyre as a hedge against the graining.
“There was a lot of the race still to go at that point when it was going from wet to dry. We fitted him with the Hard and everyone around him was on Mediums.
“Had they grained, then he would have just romped through them to an easy win.
“And while that might sound fanciful, look what happened to Piastri. His car was going backwards at a very, very swift rate. His tyres did grain.
“It was right on the cusp of graining or not graining. We fitted George with the Hard because that was his best shot of winning.
“And then just to sort of spread our bets, we fitted Lewis with the Medium.”
A second Safety Car on Lap 54 would scupper Mercedes’ plan, but the side took the available opening to move both cars onto new slick rubber for the closing stages.
Russell would switch onto the Mediums as Hamilton went onto the Hard and that proved decisive as the former passed his team-mate to claim the last podium place.
Allison has noted how the respective allocations the pair had remaining is what led Hamilton to be placed at a disadvantage in comparison to Russell in the final stint.
“When the track gradually dried up and went to wet, we did not put Lewis on the Hard tyre,” Allison acknowledged. “We put him on the Medium tyre.
“We used up his final fresh set of Mediums to give him the car on the track, on the tyre that subsequently was shown to be the quicker tyre.
“Later in the race, when we stopped behind the Safety Car to put Lewis onto a fresh set of tyres, and then we switched him from the Medium to the Hard.
“That decision was the correct one because Lewis had a completely free stop. He was not threatened by anyone from behind.
“There was a Safety Car, which meant that he would be able to close back up on who was ever ahead of him and be in the trail behind the safety car, but he would be on fresh rubber.”
“Those ahead of him, other than his team-mate, would be on used rubber, and it is not a question whether a brand new Hard would be quicker than a 12, 13 lap old Medium.
“While he might have preferred a new Medium, there were no new Mediums to have. That was not an option.
“The only new tyre we had was a Hard, and that was going to be quicker than anything that was ahead of him on the track.
“That is why he ended up on the Hard and definitely faster than the McLarens and the Red Bull.”
