SoulCycle's co-founders share 3 things to look for in a potential business partner

Elizabeth Cutler and Julie Rice have been on an incredible tandem ride for the last decade. They are the co-founders of the fitness phenomenon SoulCycle. And without each other, the co-founders say they wouldn't have made it.

"One plus one is way more than two," says Cutler in a conversation with CNBC at the Iconic entrepreneurship conference in Boston. "If you find the right co-founder, it's exponential."

Rice and Cutler met in 2005, set up on a "blind date" by a fitness instructor who knew the two women were both interested in starting a fitness business. Five months later, in 2006, their first studio opened on the Upper West Side of Manhattan.

Since then, the stationary bike workout set to dance music in a candlelit room has become wildly popular, evoking a cultlike devotion.

There are 66 gym locations across the country, according to the website, and in 2014, SoulCycle had revenues of $112 million, up from $36.2 million in 2012. Profit in 2014 was $26.5 million, up from $7.8 million two years prior. (The co-founders won't disclose more current company financials. These figures are pulled from a financial document filed with the Securities and Exchange Commission ahead of the company's impending IPO.)

The two women have largely divided the responsibilities. Cutler handles business development, technology and real estate. Rice manages people, staffing, instructor training, public relations, design and retail. The "yin and yang" of their skill sets is one reason the business has been successful, according to Rice.

"Things that seem impossible or would have caused me to stop running forward or might have kept the business at a certain level — those aren't problems for Elizabeth," said Rice. "There are different obstacles that seem crazy for each of us, so when I can't carry the ball any further because I have hit a wall, that's actually where she picks it up and vice versa. None of the things that haunt either of us are problems for the other."

Rice and Cutler have stepped out of their role running the day-to-day operations of SoulCycle, though they remain on the company's board so that they can build another company. The duo was tight-lipped about what they will be doing next, though they did say they will continue working together.

Clearly, Rice and Cutler have found and maintained a successful co-founder relationship. Here are the three must-haves the SoulCycle duo suggest other entrepreneurs look for in a potential co-founder.

1. An "all in" work ethic. "The No. 1 most important thing is super-tactical, and it is work ethic. If you do not have the same work ethic as the person that you are partnering with, that is the No. 1 recipe for disaster," said Cutler.

When you are getting a start-up off the ground, you will be troubleshooting problems at all hours, and you need to know that you can trust your partner to be there.

"Entrepreneurs need to work 24-7. There are no office hours. There is no right time for the pipes to break in your first location. There is no good time for an emergency trip across the country because you might have found your second location," said Rice. "Or your technology is melting down in the middle of the night. Or somebody has hacked your bank account," continued Cutler.

Elizabeth Cutler and Julie Rice.
David A. Grogan | CNBC

2. Willingness to communicate. As co-founders, you will go through a lot together. A person you are considering to be a co-founder needs to show that he or she is willing to listen and work through differences of opinions.

"If you really care about the relationship, you have got to make sure you are with a person who wants to evolve and who wants to communicate. And if the person doesn't want to do that, it is going to be really tough to have a long-lasting partnership," said Cutler.

Cutler and Rice admit it hasn't always been easy. Early on, they hired a coach to help them sort through communications struggles that inevitably came up in the course of getting a business off the ground. Cutler said she found the coach in the middle of the night on the internet when she and Rice were caught in a fight. They still use the same coach.

"If you do not have the same work ethic as the person that you are partnering with, that is the No. 1 recipe for disaster." -Elizabeth Cutler, co-founder of SoulCycle

Growing a business together depends on an ability and willingness to work through differences.

"You know from the beginning if somebody is a good listener. It doesn't matter who is right if it is the wrong idea for the business. So being successful is more important than being right," said Rice. "Putting your ego aside and really taking a minute to process what somebody else's idea is — even if you are sure that yours is the very best."

3. That "ding" in your gut. Cutler said she knew when she met her husband that he was the right man for her. And she also knew that Rice was the right business partner. She had that "ding" in her brain.

"My aunt used to say, you don't have to think twice about buying a good handbag. When you know it is your handbag, get the handbag. It's kind of like that with partnerships and husbands," said Cutler. "You have got to listen to your gut and know if this is the right thing. And if this is not the right thing, you have got to keep going."