BARCELONA, Spain -- Haas team boss Guenther Steiner believes Mercedes, Ferrari and Red Bull are already 1.5s ahead of the rest of the field.
With seven of eight days of pre-season testing completed it is still difficult to predict a definitive pecking order for this year's grid. Ferrari impressed on Thursday with the quickest lap time of winter so far, but Mercedes and Red Bull's comparative pace looks set to be an unknown until the Australian Grand Prix.
Despite the uncertainty over who will be the car to beat in 2017, Steiner is sure the top three will be on their own out in front when true performance levels are revealed.
When asked on Thursday how far the top three teams were ahead, Steiner said: "I think one and a half second between the top three and the other ones. It's big. It's between one and one and a half seconds I think."
Many have predicted an "arms race" throughout 2017 as a result of the huge car regulation changes which have come into force this season. Steiner thinks the midfield teams will make good gains relative to each other but that the top three might be unreachable in the early stages.
"[The gap] will not get smaller. It will not get smaller in my opinion. The gains further up you get, the smaller they get so the smaller teams can make bigger gains because they are further behind and we see what the other people are doing, so I think the gap will not change a lot during the season. It's just for the top ones, it will be more difficult to make gains.
"Not that it's easy to make them but we can look at what the other ones are doing and are gains will be bigger because we are further behind. To predict it to the tenth of the second, I'm not brave enough to do that as well. If I could look into the future I wouldn't be standing here I guess!"
With Haas sharing an engine and many parts with Ferrari, Steiner was then asked where such a big gap would come from.
"It's aero," he replied. "The big teams will always have more resources to do it and this is to be expected. I think there is no surprise that Ferrari and Mercedes and Red Bull can come out better than anyone else. They've got more resources to do more testing and that is what it is."
Though he has forecast a big gap between the leading pack and the rest, Steiner expects the right midfield battle behind will be led by Williams in the early stages of the season.
"I think the Williams is a little bit better than the big group .... I don't know about the Renault. We need a few more days and in Australia we find out. It's getting quite clear."