Gunther Steiner has said that only time will tell if Haas's decision to abandon the 2017 car project quite early was the right one.

The American team's boss made an early call this year to move the focus to the 2018 car, which is hurting performance at the end of this season.

"We took a decision to change focus to the 2018 car because we wanted to make some fundamental changes that we could not transfer 100% from this car," he told Ekstra Bladet.

However, Steiner acknowledges that the project shift from 2017 to 2018 may actually have occurred too early.

"We stopped a bit early, in hindsight," he said.

"Should we have done that? I don't know. The verdict will only come in February when we test - whether it was worth it or not.

"Right now we have a nice wind tunnel model with a lot of numbers, but I don't know what the teams that further developed their 2017 car can carry over to their 2018 car.

"We will only find out when we see them all on the track."

Like all the 2018 cars, Haas's next machine will have to be fitted with 'Halo', but Steiner said that the team has not been focused on track testing the device in free practice this year.

"To be honest, until next year, we have other priorities for practice other than Halo," he said.

Haas have picked up 47 points in the 2017 championship.