As the first rider shot down 108 stairs toward the river flats and a waiting police car, bike riders at the top said they grew apprehensive.

The two police officers drove to the base of the stairs below Riverbend Commons and waited for the others to descend, while the remaining bikers pondered the officers’ next move.

“Nobody really likes to have run-ins with them,” local “urban assault” biker Charlie Denis said.

Luckily for Denis and the group, the officers merely wanted to see them speed down the stairs – which they later did.

The possibility of being ticketed also keeps other action-sports enthusiasts around campus weary.

“It’s something that we deal with, pretty much,” Denis said.

BMX bikers, skateboarders and in-line skaters grind ledges, while urban assault bikers jump staircases and drop off loading docks around campus.

Such activity keeps University officials busy trying to maintain safety and protect school property.

To prevent people from grinding on curbs and other edges, Facilities Management attached metal bumpers throughout campus.

“They’re meant to discourage, particularly skateboards, from riding ledges,” Facilities Management spokeswoman Jenn Rowe said.

Grinding occurs when a person slides along a surface’s hard edge, primarily with a skateboard, in-line skates or a bike.

For instance, a skateboarder would use one or both of the board’s axles to slide.

To prevent grinding, bumpers were added outside of Coffman Union, in front of the East Bank recreation center and McNamara alumni center, among other places.

Skateboarder Danny Vogel said bumpers stop people from skating in those areas, but he is not sure they are beneficial.

“It makes it look a little tacky,” Vogel, a business management senior, said.

Besides, “street skaters” will find other places to go, he said.

Steve Harkman, an in-line skater and aerospace engineering senior, said he thinks bumpers are unwarranted.

Unlike skateboards and BMX bikes, skates made today cause little damage to surfaces, he said.

Skates’ grind plates are made of nonmetallic material, so they do not ruin a ledge.

Like others, Harkman said he and his friends cannot escape the wrath of police, security guards, janitors and pedestrians.

“You get a mixed reaction from cops,” said Thor Shellum, an “urban assault” rider and mechanical engineering senior. “The people that stop you usually are security guards.”

The University and the city of Minneapolis have ordinances restricting bikes, skateboards and in-line skates to certain areas.

“The reason the ordinance is there is because people have been injured,” University Deputy Police Chief Steve Johnson said.

Minneapolis police officer Ron Reier said he agrees.

“It’s against the law. It’s a safety issue and it’s a property- damage issue,” he said.

Minneapolis invested thousands of dollars in creating bike lanes, and they should be used, Reier said.

If people want to do tricks, they can go to a skate park and do it legally, he said.

Most Twin Cities-area skate parks welcome all ages, abilities and styles.

In addition to street skating, skateboarder and junior Bob Elmergreen said he uses parks, but some, such as 3rd Lair Skatepark in Golden Valley, Minn., charge admission and can get crowded.