Barcelona will test Mercedes' recent improvements, says Allison

Having displayed eye-catching form over the course of the wild weekend of the Canadian Grand Prix, Mercedes technical director James Allison said that his team will only be able to assess the performance of its heavily-upgraded W15 when the field returns to the more conventional track of Barcelona.

In the last three rounds, Mercedes have shown clear indications of their improved performance thanks to a development push.

The improved pace enabled George Russell to claim his first pole position of the year in Canada and secure the Anglo-German's outfit's first podium finish on the following day.

However, with Mercedes having struggled for consistency and outright pace in the opening stages of the season, the team is yet to confirm in the next rounds whether they really managed to make progress with their W15.

"The changes we've made are definitely making this car a better car. And that will be true at every circuit we go to. I think that Montreal made it look a little quicker than we have a natural right to command at the  coming races. So the little 'dreamery' part of me hopes that we'll be right at the sharp end of Barcelona.

"I think it more likely that we will be competitive, but not right at the front. Because the next tracks are a little bit of a sterner test of a car. Hot asphalt, wider   cornering speeds, and so on.

"However, that said, I  also know what we've got coming. I also know what  we're planning to further improve the car. And our  challenge is just to keep those upgrades arriving at a pace that the others can't keep up with. 

"And in doing that, just bullying our car to the   front by virtue of the effort made by everybody  here over the coming weeks and months to get the car so that it can have its Montreal weekend or better at any track that we face in the future.

The two Mercedes drivers dominated the middle part of qualifying in Montreal, but they were unable to improve their times in the all-important Q3 session. In fact, George Russell's pole time was three tenths of a second slower than what he achieved in Q2.

Based on this experience, Allison suggested that his engineers still need to widen the W15's operating window in order to get the best out of it in every condition.

"All of the other cars in that top seven were able to improve on their times in the Q2, except the W15. I think we have broadened it substantially.

"I think there's more we still need to do, and we'll  know, I guess, for sure, when we go to the next track, which is Barcelona, because there is really a very substantial range of cornering conditions. There is also a much hotter track, and so that  will be quite a stern test of a vehicle.

Allison claimed that the difference between Hamilton and Russell and the slight dip in performance in Q3 were down to the tyre management. As a result of a tweak to the sporting regulation, drivers have a much tougher task on their hand with the new rules heavily limiting the maximum temperatures team are allowed to heat up their tyres to.

"Drivers have a very difficult job to do on an out lap. We are not allowed in the garages to heat the tyres to higher than 70 degrees, but the tyres themselves need to be hotter than that to get the  best from them on the lap.

"They have to manage the  out lap of the qualifying before their flying lap,  such that they bring the front tyres and the rear tyres into their window, while also respecting the minimum times that the race director has imposed on them as a thing, and not blocking cars behind them, and it's very, very difficult out lap to get the tyres in the right place.

"And it doesn't take much by way of being a degree here, cold here or there, to just take the edge off them. And then they launch into the first corners. If the car is not as well prepared as it might be, then the  tyres will just slip a little bit on the surface.

"That will make them overheat on the surface, and you lose a bit of grip, and then it will just run away from you. Not talking about by much, but look at the front end of the grid. Lewis was only the blink of an eye slower than George, and George was on pole, and Lewis was seventh.

"So they're fussy in as much as it's very hard to get the absolute best from them, and the gaps between you and your competitors are tiny. So you're punished very heavily for very, very small transgressions."

Mercedes' new front wing has been in the focus for several weeks with the team having brought its introduction forward by two weeks. It meant that only one front wing was available for the Monaco Grand Prix, and the team elected to equip George Russell's car with the upgraded part.

Since the Monaco round, Mercedes have managed to produce three pieces which meant that both drivers received the upgraded front wing. Allison said that the new part brought the car into a much better operating window as it led to a much better overall aerodynamic balance.

"I would say yes. We'd got an idea of how it would  behave, because we'd run it the previous race in  Monaco with just George on that occasion.

"We had two of them in Montreal, and we expected it to perform well. We expected it to deliver a bit  more in Canada than it did in Monaco, because the Canada circuits, although unusual, it's more of  a normal circuit than Monaco was.

"And it did, it delivered more performance, it made the car feel easy to drive, well-balanced, and made the car the driver's friend rather than the thing they'd been  fighting, which has been what has been problematic in the opening part of the season for us," concluded Allison.