Raikkonen at a loss to explain Ferrari pace variations

Kimi Raikkonen's US Grand Prix ended after 39 laps when the Ferrari driver was forced to call it a day through no fault of his own.

Raikkonen was enjoying a solid, although uneventful, run in the top 5 when a pit stop blunder sealed his fate during his third stop of the afternoon.

The Finn pulled away too quickly after changing to Soft tyres but in the process yanked a tyre gun off a rear wheel, damaging the car's nut and stub assembly.

Raikkonen stopped at the exit of the pitlane and rolled his car back down the slope and onto the pit complex where he retired.

The mishap not only put the Finn out of the race, it also earned the Scuderia a €5,000 fine for unsafe release.

"I don't really know what happened, obviously we have to find out," said Kimi Raikkonen.

"The green light came on, and obviously I will go once there's a green light. Why it came on while we were not ready, I don't know. I saw some sparks coming out and asked if it was okay, and was told to stop."

Up to that point, Raikkonen had been running in fourth position but without any chance of catching the Mercedes and Red Bull up the road.

The Finn initially made his first stop for Soft tyres as early as lap 9, Ferrari evidently banking on a somewhat surprising three-stop strategy which came about as a result of a disappointing run on the Soft compound.

"We expected more from the Soft tyres, and we changed when it was needed, but in the end it didn't make any difference."

The Finn was at a loss to explain exactly why the Ferrari was less competitive in Austin compared to Japan two weeks ago.

"I have no idea, we've seen many differences from circuit to circuit. Perhaps it was the conditions or something which explain why we weren't as close as we were two weeks ago. The car's balance is quite good but we just need more grip overall to go faster."

Ferrari appears indeed to be lacking consistency with regard to its overall pace, a weakness which perhaps points to set-up difficulties, which Raikkonen did not deny.

"It's always going to be difficult to set-up the car exactly how you want, it depends on many conditions. I think when it's very windy it seems to affect us more than we like.

"Obviously we tried different things on Friday, but sometimes it's difficult when you don't have a lot of time to make the changes to work.

"Yesterday the balance was as good as it was going to get but unfortunately the lap time is not where it should be."

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