Haas boss Guenther Steiner has claimed the performance of the midfield teams is dictated by tyres rather than the cars.

This year, the Pirelli compounds have proven very difficult for teams to optimise, due to narrow optimum temperature windows which vary from circuit to circuit.

Haas and their partner Ferrari have been two teams that have struggled more than most and Montreal's long straights and slow corners are only expected to exaggerate that problem.

“I think the car is better than last year’s car, it’s more consistent, the balance is better," Steiner told RaceFans in Canada on Thursday.

“[The problem is] we cannot get the tyres to work but I would say that if you look in the paddock everybody has a complaint about these tyres being in or out. That is the biggest thing, and I think actually distracts from how good the car is.

“Our car was good in a few places, completely useless in other ones and we know exactly why but we don’t know how to fix it because we cannot get the tyre to work.

"It’s not only that we have got that problem, everybody has got that problem and you can see also in the midfield everybody is very close together but it doesn’t really show you how quick the car is, it shows you more who got the tyres to work and who not.

"It’s a championship of the tyre working range, who can get it and who not, at the moment.”

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The Haas chief did admit the issue was less prevalent on the softer compounds, perhaps unsurprisingly, and suggested that perhaps Pirelli should consider being more aggressive in their tyre choices.

While not responding to Steiner, motorsport chief Mario Isola did explain why tyre performance is now of such great importance.

"If you consider the midfield, we have five or six teams that are within 0.2 seconds of each other," he was quoted by F1i.com.

"It has become very, very important to find any thousandths of a second. It can create a difference in qualifying position or in the race pace or whatever.

"That's why they [the teams] are so focused on the tyres, because probably if you are able to use the tyre in the best possible way you find performance.

"To find such performance with the power unit, or downforce is a bit more difficult."