Lewis Hamilton has attributed the gap to Nico Rosberg in FP2 at the United States Grand Prix to "disastrous" brake settings changes.
Having been fastest in the opening practice session, Hamilton dropped 0.3s behind team-mate Rosberg on Friday afternoon and was also beaten by Daniel Ricciardo's Red Bull. Explaining the gap, Hamilton pointed to problems with the brakes which he is confident will be rectified by final practice.
"I had some problems in P2 with the braking, so that was losing me a lot of time," Hamilton said. "FP1 was looking pretty good and I made some changes for FP2 which were good, but I had some underlying issues with the braking system so hopefully that’s fixed.
"I wasn’t comfortable in the second session. We made some changes that generally made the car better, but we made some brake setting changes that were disastrous and I was struggling to finish a lap without oversteer, but we will fix that."
Asked about Red Bull's pace following a strong long run from Ricciardo, Hamilton believes Mercedes does not have much of an advantage in Austin.
"I think they are going to be very quick this weekend, it looks like they will be very quick, so it’s definitely going to be a challenge. I guess more of our pace will show up [in qualifying] and we will get a better understanding, but they are definitely not far behind."
However, Hamilton is confident Mercedes will be able to benefit from better tyre management on Sunday based on his Friday running.
"For me the super-soft was really good. It was lasting relatively well and wasn’t as bad for us as it was potentially for some others. It is the faster tyre so people will start on it and then we’ll see how long people can last on it on the first stint."
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