Brad Keselowsk finally got to see how the other half lives.

Keselowski, the 2012 NASCAR Sprint Cup Series champion, tested one of team owner Roger Penske's Verizon IndyCar Series entries Wednesday on the 4.08-mile Road America road course in Elkhart Lake, Wis.

The open-whel car Keselowski drove belonged to Team Penske's Simon Pagenaud.

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"I've always wanted to drive an Indy car. I think (Penske Racing President) Tim Cindric knew that," Keselowski said. "The opportunity came up to dip my toes in the water and kind of expand my knowledge base and put it in the back of my mind for wherever it goes, I don't know. But it was a heck of an opportunity and I'm glad to have a chance."

The experience was eye opening for Keselowski.

"First thing I told Simon (after the test) is he has a very secure job, at least from me," Keselowski said. "I've got a lot of respect for him and his team, everyone at Team Penske. This (No.) 22 Menards team, they did a great job today and I had a lot of fun going with them. Simon was fast, really fast and gave me a good rabbit to chase. I learned a ton today and had a lot of fun. I've got to let it soak in here to think about all of it. It was a heck of a day here at Road America."

With less than half the weight and more than twice the downforce, the Indy car drivers much better than the stock cars do on a road course.

"It sure was getting in the corners a lot deeper," Keselowski said. "I think the Indy car just pulls so many G's through the center of the corner and in the brake zone. You have to build confidence in it because the stock car does everything it can to wreck your confidence and in the Indy car it's important to have confidence. So you have to kind of unlearn everything you learned in a stock car to be good in these cars. That's a heck of a process but a fun one.

"It's certainly a different feel, trying to get acclimated to a different seat and you lean back more. I was kind of sitting in Simon's seat and it doesn't always fit you perfect, so it wears you out pretty quick. But it's a good way to get worn out."