AUSTIN, Texas -- Lewis Hamilton said an issue under braking cost him lap time during second practice for the U.S. Grand Prix, but is confident it can be resolved ahead of qualifying on Saturday.
Hamilton was third fastest in the second practice session and 0.291s off teammate Nico Rosberg, who set the quickest time of all. Hamilton said changes to his car's brake settings between FP1 and FP2 made it particularly difficult to drive when pushing to the limit.
"I wasn't comfortable in the second session," he said. "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 tomorrow."
Asked how much he could improve, he added: "There is loads of room. Once we fix the brake issue we will be back on pace, which is good."
Daniel Ricciardo's Red Bull split Rosberg and Hamilton in FP2 and Hamilton expects the Australian to challenge Mercedes this weekend.
"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 tomorrow and we will get a better understanding, but they are definitely not far behind."