The 27-year-old, a Le Mans 24 Hours winner and world endurance champion, has not driven a single-seater since 2012 and last tested in Formula One in 2010 when V8 engines were still around.
Appearing at his first Formula One news conference on Thursday, the latest Toro Rosso driver recognised he would have "a bit on my hands" in Friday practice at the Circuit of the Americas.
"All the friends I have in the sport I’ve been asking for a bit of advice," he said, mentioning Australians Ricciardo and Webber.
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Now-retired, his former Porsche team mate Webber is in Austin as a television pundit while Ricciardo will be chasing a podium place for Red Bull.
"I saw Mark this morning for breakfast," said Hartley.
"I saw Daniel, who is one of my best buddies as well, two nights ago. I asked him for all the advice I could manage to get out of him regarding tyres.
"Some of it is going to come down to driving free practice one, seeing how I go and then asking some of those questions. A lot of them aren’t really relevant until I’ve actually experienced the car," he added.
The first Kiwi in Formula One for 33 years, Hartley got the drive after it was decided that French rookie Pierre Gasly should finish off the Super Formula One season in Japan this weekend.
Gasly can win that title for his Mugen Honda team, important in the context of Honda becoming Toro Rosso's engine partners next season.
Hartley tested for Red Bull-owned Toro Rosso in 2009 but was released by the energy drink company in 2010. He went away and made his name in sportscars instead.
And then Porsche announced they were pulling out of Le Mans and world endurance as a works team. Hartley rang Red Bull's motorsport consultant Helmut Marko to sound him out.
"I’m a different driver than I was 10 years ago, I’ve learned a lot, and if there is ever an opportunity I am ready," he told him.
As an 18-year-old, testing in Formula One and struggling to deal with the pressure, he had not been ready.
"I stopped enjoying it, I wasn’t happy; I was pretty young and away from home. When the Formula One dream, so to speak, stopped in 2010, I picked myself up, I found endurance racing and yeah, I have learned a lot from that experience," he said.
"I’m a lot stronger than I was back then, basically...I like to think I’m ready now."
Marko took it on board and called back three months later. Whether he stays in Formula One beyond this weekend remains to be seen.
"I was looking at Indy Car and I still am. Nothing confirmed for next season yet," said Hartley.
(Reporting by Alan Baldwin, editing by Ed Osmond)
