An unhinged security guard wrestled a passing cyclist to the pavement amid an argument over bike lane etiquette with a different pedal pusher, video posted online shows.

The Feb. 25 altercation kicked off around 9 p.m., when the unidentified driver blindly walked into a bike lane on Sixth Avenue near 25th Street in Manhattan while staring at his phone, making Vincenzo Tran, who posted the video, lose control of his $3,000 motorized unicycle and collide with a parked car, Tran told The Post.

The rent-a-cop then claims he doesn’t have to look both ways before stepping into the street.

“Listen to me! This is a car, this is the street! You have to watch out for me!” the disturbed motorist bawls as he points between his car and the bike lane, according to video posted to YouTube.

“This is a bike lane, stupid,” Tran responds.

“Yeah, I know it’s a bike lane, but you have to give way to me! I’m a pedestrian,” the guard gripes.

“So what, you don’t have to watch where you’re going? You’re stupid,” Tran shoots back.

As the driver is gesticulating, he smacks into a passing cyclist, who is nearly knocked off his bike. That’s when the irate NYPD wannabe runs over to the cyclist and tackles him to the ground, video shows.

Before he can deal any blows, the man is pulled off the cyclist, revealing a gun holstered on his hip.

“What are you doing? Chill! You don’t do that to people,” one passerby shouts, “He’s a young-ass kid, what the f–k is wrong with you?”

After the scuffle, the man starts walking to his car, once again in the bike lane as more cyclists pedal around him, video shows.

“White privilege motherf–ker, bro. You want to step out onto the bike lane, and then you want to say that you’re right? You’re an a–hole,” Tran can be heard shouting at the man, who just stands by his car with the door open.

“Once I mentioned cops, he left,” Tran told The Post, adding that he did not file a police report.

Harvard Protection, whose name was printed on the irate man’s car, is a Manhattan-based security company with offices in Iselin, NJ. The company did not return calls for comment, nor did it return calls from Tran about the damage done to his motorized unicycle.