After just four years in operation, Peloton, the indoor, interactive cycling platform, is no longer just that. It is going beyond the bike, introducing a high-tech treadmill that builds on the same technology and social interaction as the bike.

The price tag when it goes on sale later this year will be about $4,000, plus the $39 monthly fee for the livestream and on-demand content. Current Peloton members, which now number in the hundreds of thousands, will not have to pay anything more for the monthly subscription. It will cover both the new treadmill and cycle.

The treadmill, which Peloton is unveiling Tuesday at the International Consumer Electronics Show, or CES, in Las Vegas, measures 18 square feet and features a huge screen, four times the size of the cycle’s screen, where runners can follow live classes and compete on a leaderboard. Buttons and dials on the side arm rails move the platform up and down and control speed.

It is a major departure for the self-proclaimed media company, which CEO John Foley says has grown to 900 employees nationwide and doubled its revenue to $400 million last year.

“The treadmill market is five times bigger than the bike market,” said Foley, adding that it has been in development for two years. “We listened to our members, and we asked them what they would want.”

The answer was a boot-camp style, circuit training workout. Peloton centered that around the treadmill, but the workouts also guide users off the apparatus and onto the floor to do core and weight training. Peloton will introduce a new line of branded weights to accompany that.

The treadmill itself employs 59 individual slats to give runners a cushier stride. It was developed using 3-D printing technology to keep costs low and speed the process.

“The second it’s done, we can put it on our prototypes in the lab,” said Maureen Coiro, senior product manager of hardware, holding one of the slats.

As rumors of a treadmill spread across the Peloton rider community over the past few months, some on its Facebook page gave big thumbs-up emojis, but others did not. A few members questioned the move away from the core brand, worrying that service and content would suffer. Foley aims to allay those concerns.

“We don’t want the Peloton bike or the treadmill to be the hero,” he said.

Foley tries to focus the heart of the business on media content, social interaction and personal growth, even as competitors like Flywheel are also selling home-cycle systems that stream classes.

“I don’t want to be cavalier about competition,” Foley said. “I think there will be real competition, but from my perspective we would be more worried about a technology company, call it an Amazon, coming into our space, versus a content company trying to figure out what Peloton does.”

Disclosure: CNBC’s parent company, Comcast/NBCUniversal, is an investor in Peloton.