Giovanni Martinez, 14, has been skateboarding at Williamsbridge Oval Park for about a year. He and his friends, a pack of teens who’ve become regulars at the Oval, use the concrete, foot-high ledges that surround the park’s trees and walkways to grind and perform tricks.

But late this summer, the Parks Department halted the tricks by installing small metal wedges that protrude from the ledges, intended to stop the wheels on a skateboard.

“We have nowhere to skate now,” said Giovanni. He said he and about 10 other skaters, his friends, were shocked when they found the wedges, which they call “stoppers.” On a recent afternoon, the group had already succeeded in removing four of them, and hammered away on a fifth.

A skate park had originally been included in the renovation plans for Oval Park in 2008, but one never materialized. The Parks Department said Community Board 7 had voted for using the funds towards other improvements (the park boasts two brand new playgrounds, which opened this summer).

Even without an official, sanctioned skate space, some of Giovanni’s friends have been riding at Oval Park for years. Now, they say their options are limited. There is a relatively new skate park by Yankee Stadium, but skaters are constantly being robbed in that area, they said.

The group considered the Bronx High School of Science campus, but were reluctant to walk all the way to the Bedford Park school. They may make the mile-long trek to the skate park at Bronx Park East in Allerton, they said, but they’re more likely to just make do at Oval Park.

“We’ll just keep skating here without the ledges,” said Bryant De la Rosa, 14.

A Parks Department spokesman said they installed the stoppers after receiving complaints from residents. The skating is also damaging a park that wasn’t designed to be skated on, the spokesman said.

A large concrete slab from one of the ledges had fallen off, sitting on the ground next to the space it used to occupy. Jean Colladon, 19, says the Parks Department blamed them for removing the ledge, but he insists they aren’t the culprits.

The teens contend that they aren’t doing anything wrong. Not robbing people, and not getting into fights.

The stoppers aren’t just peeving the teens who ride there, but their parents too.

“When my son called me yesterday, I was upset,” said Lisa Martinez, mother of Giovanni, adding that the boys cause no trouble. “My kids were raised in this park.”

Doug Condit, a member of Friends of Williamsbridge Oval, an advocacy group for the park, brings the skaters water and soda when he walks his dog. It was Friends of the Oval that had originally recommended an area for skateboarders at the park.

Condit called the teens “clean cut.” He said they even show up in the morning with brooms to clean up the park. They shovel snow in the winter.

He was so displeased with the installation of the stoppers, he said, that he e-mailed Deputy Parks Commissioner Liam Kavanagh on the teens’ behalf. He said Kavanagh told him the department would look into finding a low-cost way to let the skaters ride.

Giovanni argues there’s also an element of danger to the newly-installed stoppers: skaters speeding across the ledges could snag their boards on them, and be sent flying. He knows the dangers skaters face, personally — while his friends wore thick-padded skate sneakers, he wore a boot. He’d recently fractured his right foot while skating around his building.

Oval Park has long been a popular spot for skaters in the area, said 12-year-old Matthew Singh, who estimated the park would see up to 50 skaters at a time during the summer. Their numbers dropped precipitously just days after the stoppers were installed.

Now, Matthew says, his group of friends is the last of the pack.