BROOKLYN, MICH. — Travis Pastrana is afraid of one thing.

It’s not jumping out of an airplane without a parachute — heck, he has done that, and the stunt has been viewed more than 6 million times on YouTube.

And it’s not screaming down a ramp on a motorcycle and soaring high into the air and doing a double backflip. Yes, he did that, too.

And it’s not BASE jumping. Or racing a motorcycle or a truck or a rally car.

And he’s not afraid of driving a stock car more than 188 m.p.h. at the Michigan International Speedway — he did that in practice Friday afternoon, recording the ninth-fastest speed.

No, he’s afraid of something far more frightening. It is something that can bring a man to his knees in awe and fear.

“Fatherhood!” the 30-year-old said, smiling. “Having a kid on the way. I’m petrified.”

Pastrana and his wife, Lyndsey Adams Hawkins Pastrana, are expecting their first child in September. Lyndsey, a professional skateboarder known as Lyn-Z, has won three gold medals in the X Games.

“For me, no matter what happens, I want to show my daughter that you have to follow your dreams and be passionate about what you do,” Pastrana said. “Wear your safety equipment. Do all you can do to protect yourself. But don’t limit yourself.”

A new world

Pastrana walked through a gate toward his Ford Mustang in the garage area at Michigan International Speedway on Friday morning. He was wearing blue jeans, a black Roush Fenway team shirt and a Red Bull baseball cap.

A group of fans swarmed around Pastrana, wanting his autograph. The fans were all younger than 40 and had grown up watching him on MTV and in the X Games.

One fan carried a box with a plastic action figure of Pastrana on a motorcycle. Another one wanted Pastrana to sign a photo from the X Games. And a third had a photo of one of Pastrana’s motorcycle stunts.

Pastrana signed some autographs, while nervously looking at his watch. He was late for a rookie meeting. “I’ll be back,” he said. “I promise. I’ll be here all weekend.”

Pastrana is friendly, funny and accommodating, but he is caught between two worlds. He was an action sports superstar, who won 11 gold medals in the X Games. Revered for his courage and guts, he has a TV show on MTV and 4.4-million fans follow him on Facebook and almost 700,000 fans follow him on Twitter.

But Pastrana has switched sports and entered a new world. He has gone from daredevil to race car driver. And no, they aren’t the same thing.

Pastrana is a lowly rookie on the Nationwide Series, trying to make it in NASCAR. “The talent is awesome,” he said.

Pastrana has 12 starts this season and has crashed three times. His highest finish was ninth in Richmond.

“There is definitely a learning curve,” said Pastrana, who will be racing in the Nationwide Series today at MIS. “Before, I didn’t know what I didn’t know. But I want to be a champion. We have a long way to go. These guys? Man, I knew they were good, but not this good.”

More than anything, he is learning how to find speed.

In action sports, speed is found through risk.

If he wanted to go faster while competing in motocross, he would just push the limit and jump a little farther.

“You can physically go faster if you are willing to take the risks,” he said. “In freestyle, if you are willing to try something that other people are afraid to do, you can win. In rally, if you trust your co-driver a little more, on a section you have never seen, if you are coming over a blind crest and you are willing to cut a little through the trees, you can make up time.”

But that doesn’t work in NASCAR.

“In NASCAR, it’s all about skill,” he said. “You have to find that edge. If you go a little too fast, you lose time. If you try to go faster, a lot of times you go slower. It’s pretty frustrating.”

A safer choice

Pastrana switched to NASCAR for the competition, to prove to himself that he could do it. Plus, he was tired of getting injured in action sports. He has no idea how many broken bones he has suffered.

“It’s hard to keep track,” Pastrana said. “I had 40 fractures in seven bones in one injury. Is that 40 breaks or one? It’s hard to keep track.”

He has had 32 surgeries and dozens of concussions. “I lost track; I don’t remember,” he said, not trying to be funny. “Two to three a year” since he was 8.

So that is why he has switched to NASCAR.

Because, as odd as it sounds, it’s safer.

He knows he could fail. He knows this was a huge risk. He could have stayed in action sports, raking in the money and living at the top, but he is driven to prove himself.

To be safe but follow his dreams.

And that is what he hopes to teach his daughter.

Then again, just wait until he has to start changing those dirty diapers. Now, that can be a scary, dangerous, action sport.