Neither car seemed the worse for the encounter, however - at least not until next time by when suddenly the backend of the Ganassi #10 snapped around and Franchitti found himself making quite the impression on the turn 3 and 4 SAFER barrier.
"The next lap I went in there and something broke in the back end of the car," said Franchitti. "The spine just snapped down. You actually see the car drop in the back there before it hit so I think the suspension "
When the race got back underway on lap 201, it was an uninterrupted green flag all the way to the finish. Hunter-Reay was still firmly in the lead, and now the opposition simply dropped away. Castroneves' long-run fuel-conservation strategy didn't pan out and after the final round of pit stops he fell back to a sixth place finish - respectable, if not quite as good as he'd hoped for.
"We took a gamble today with the pit strategy in the #3," he said later. "The car was running really well and we thought we could be aggressive with our plan. We definitely had a car that could win the race today but I am still happy with our result. I will take sixth place and look to do better next week at Iowa."
The pit stops and final cautions had popped Tony Kanaan up into second place ahead of Oriol Servia and James Hinchcliffe for that final stint, and apart from Hinch getting the better of Servia eight laps form the end, that's how the race finished.
"It's amazing," said Hunter-Reay, celebrating his first win since last year's controversial victory at New Hampshire Motor Speedway. He's also previously won at the Milwaukee Mile, having taken the chequered flag in the CART series in 2004.
"What a race! I know we would all have liked to see a little more passing, but from the car it was so busy, just trying to hang on to it," he went on. "It's unreal, hanging on to those last few restarts were too much. I don't need that!"
Finishing in second, Tony Kanaan admitted that he'd had nothing more with which to challenge for the win. "I didn't have anything at the end for Ryan," he said. "I did something I never do, I try to protect my spot because I couldn't stay with Ryan."
The race winner was particularly happy that the Milwaukee event had been a success in terms of its staging at the crowd attendance, after fears that low crowd numbers last year might have meant that one of the most venerable US oval racing tracks might not be hosting any more IndyCar races in the future.
"Milwaukee has been so important to IndyCar for so long - I think this is a huge event for Milwaukee, these two belong together," he said, thanking his team owner Michael Andretti for stepping in as race promoter when no one else seemed willing. "I really thank Michael for sticking his neck out coming back here and really doing it the right way."