Romain Grosjean says Pirelli is aware its current F1 tyres are not good enough, but the Haas driver pins the blame on a lack of testing rather than the tyre supplier itself.
Grosjean was one of a number of drivers who were vocal about the high tyre pressures prescribed by Pirelli for the Chinese Grand Prix last weekend. Ever since two tyre failures at last year's Belgian Grand Prix the FIA has enforced Pirelli's pressure and temperature guidelines at each race, with penalties for teams that try to gain an advantage by going outside the guidelines.
In China, Grosjean said the tyre pressures were "ridiculously" high and on Sunday revealed he took his complaints directly to Pirelli.
"I did and they explained to me that the [aerodynamic] load is high and they have to put high tyre pressures, but it's kind of none of my business," Grosjean said. "I would like to run proper tyre pressures, so it was very good that we had the discussions.
"They know that their tyre is not good enough but we know that there is no testing so it is very difficult for them. Today in the race I think it was quite hard for everyone, the degradation was quite big, so not ideal."
Grosjean admitted his comments on Friday were borne out of frustration.
"I think Jenson had the same opinion as me on Friday, but frustration got the better of me a bit on Friday and I don't want to blame Pirelli for anything. Again, they don't have any testing so how can they improve their product? So I think that's why we're not too talkative about it. Some people [other teams] did a better job than we did within the constraints."
Ahead of major changes to the tyre size and characteristics in 2017, Pirelli has been granted more in-season tests this year in preparation.