Pastor Maldonado believes the tight restrictions imposed on race drivers at this week's Silverstone test have left it impossible to judge what impact new tyres will have on the competitive order.
Following clarifications issued by the FIA and Pirelli that race drivers would not be allowed to run with new parts or tweak set-up during tyre runs, Maldonado thinks that this week's test will not deliver a clear picture about what to expect from Hungary.
"We could change nothing," the Williams driver told AUTOSPORT when asked about how restricted he was. "No starts; no set-ups, no pressures. Nothing.
"It was quite limited by Pirelli and the FIA, so we just tested the different compounds of tyres they give us - medium, hard and prototype.
"I think we still need to work around these tyres to find out more - but we couldn't do it today because we were a bit limited. It will be interesting to work around the tyres and see if the car can improve around them."
Although Maldonado believes the impact that the new tyres will have on form cannot be judged yet, he reckons that the 2012 construction has delivered a better consistency than the tyres they will be replacing.
"I think there is an improvement in terms of reliability and performance," he said.
"Maybe the tyres are not quicker than what we had in the past, but they are very consistent, which is quite good.
"But we don't have exactly a clear idea because we don't know - as always in testing. We don't' know what the others are testing but it seems to be quite normal and good."