Andretti Autosport team manager Rob Edwards says the team need to figure out the unusual behavior of the tires on the St. Petersburg track surface.
Said Edwards: “There were very few cars – maybe three – that were able to set a fast time later in the first session, and we’re not sure why.
“Right now we’re heading off to try and work out whether the track’s not rubbering in, or maybe the [black] hard compound tires are dropping off.
“There were sessions [for World Challenge, USF2000, Pro Mazda and Indy Lights] yesterday and earlier today that cleaned the track and laid a lot of rubber down, and maybe that’s what made the earlier part of the session faster.”
Edwards said all four Andretti Autosport drivers had suffered understeer, with Ryan Hunter-Reay leading the way in fifth.
“I think by race time we will have defined the characteristics of the tires and the track,” said Edwards. “With stints of 25-30 laps, that will be vital.”