"I got into a kind of mixup as well with Alex Tagliani and hit the wall. Then finally we had an issue with the left paddle shifter in the steering wheel so I wasn't able to downshift. It was just one of those days."
The Belle Isle, on the outskirts of Detroit, is a road circuit, so Dixon should be able to move himself back up the table.
Hartley is back in a Daytona Prototype for round five of his Grand-Am Rolex Sports Car Series.
"I love street circuits and it should throw up a few safety cars, which should work to our favour," said Hartley. "Street tracks are great and there's something about driving on a bumpy road around a city flat out with guard rails centimetres from the car. I can't wait for my first street race in America.
"They say it's a bit different over there and I hear the surface is very, very bumpy and a lot of cars in the past have fallen victim to the walls. IndyCar is there as well so there'll be a big crowd."
Hartley's co-driver, Scott Meyer, will probably qualify the car and start the race with Hartley taking over the wheel for the last stint. Meyer is not a full-time professional racer as Hartley is, and is a little off the Kiwi's pace.
"We've been on the pace every time we've raced and we should really have won at the Circuit of The Americas. I've set fastest race laps and been at the front on a few occasions. The pace is definitely there to win a race and it just all needs to come together. I'm confident Detroit is the place where it will all come together."
The former Red Bull Racing junior development driver has been either on the pace or leading his class every time he jumps in either his LMP2 car in Europe or the Daytona Prototype in the US. However, he has been beset in recent races by mechanical gremlins or driver error.
"I was pretty bloody quick in the wet at Silverstone and stormed to the front. I had a hefty lead but the rain kept getting heavier and I spun off. The thing about that race, though, is just about everyone went off and the race was eventually red flagged," said Hartley.
"At the race in America I was quick again and leading with 15 minutes to go when I came into contact with a GT3 car I was passing."
Hartley is in for a pretty busy five weeks of racing on alternative sides of the Atlantic and between weekends he'll have his Mercedes Formula One simulator duties to continue.
"I've got Detroit this weekend, Le Mans test day next weekend, then back to Ohio for another Grand-Am race and then I'm back in Europe for the Le Mans 24, which is a full week, and then I've the Watkins Glen six-hour back in America.
"A busy time but it's great to be getting that much seat time," said Hartley.
