The Sprockettes are preparing to ride off into the sunset.

The all-women bike performance group will tango, joust and shimmy with their bicycles for the last time this December.

The troupe started 15 years ago, using BMX bikes as both dance partners and stunt props to spread messages of body positivity, self-expression and, naturally, cycling advocacy. But even now, its members have trouble classifying exactly what it is they do.

“It’s kind of hard to describe,” says member Angela Derr, who goes by the stage name Agent Unlikely. “It’s one of those things you have to see.”

An average routine begins like that of a normal dance troupe, with stomping and coordinated kicks, until the bikes get involved. The Sprockettes—often clad in pink-and-black attire—stand on the rides three at a time, can pedal upside down and have even used bike inner tubes as whips.

The group’s tenure has included running the Sprockettes Girls’ Camp since 2011, and traveling with New Belgium Brewing’s Tour de Fat down the West Coast. Their moves inspired other bike troupes to form in Chicago, San Francisco, England and Japan.

But keeping the group going has proven difficult. There are three Sprockettes left. Recruiting more has been hard, so Derr says the group decided it was time to call it quits. The crew will give its last performance Dec. 1 at BikeCraft, an annual Portland convention for artists and designers.

“We’re trying to make it a really good last year,” Derr says. “We’re excited for new opportunities, and to be more involved in the bike community that we came from.”