Formula one drivers remain unimpressed with the design of Bridgestone's 2010 tyre.
Up and down pitlane, 'getting these tyres to work' is the enigmatic and universal question, which for some teams and drivers is more of a problem than elsewhere.
Ferrari's Felipe Massa, for example, needs warm weather, a soft tyre compound and an abrasive track surface to be as quick as his teammate Fernando Alonso.
"It has little to do with racing when you are so dependent on the tyres," the Brazilian is quoted by Germany's Auto Motor und Sport.
He is frustrated that some of his rivals, like McLaren's Lewis Hamilton, have the Bridgestone's working "on the first flying lap".
Nico Rosberg said in Canada that his problem was getting the car to work with the tyres, and even teammate Michael Schumacher's vast experience of 256 grands prix is not providing the answer.
"These tires are a puzzle that is very difficult to work out," said the Mercedes driver.
Schumacher added: "Often it changes from day to day, due to one or two factors."
It is believed the issue is the design of the tyre carcass, much stiffer than in the past in order to prevent the type of problem experienced by Michelin at Indianapolis in 2005.
But it means some drivers have trouble getting the tyre up to temperature.
"You can see quite clearly that Hamilton's aggressive driving style means he can get the tyres working more easily than Button can," said Mercedes team boss Ross Brawn.