The Scot wrote in a column for the Daily Record newspaper that the new single-tyre regulation is taking both car and driver 'to the limit.'
"I'm still recovering from Barcelona," the 34-year-old - who flatspotted a tyre and drove the rest of the race with severe vibration - revealed.
DC said he noticed that Williams' front Michelins were 'down to the canvas' in parc ferme at the end of the race.
"We are definitely on the edge now," said Coulthard, "and in a difficult area with potential for ... problems."