Environment Transportation She Just Cycled 184 Mph, Twice as Fast as a Cheetah's Top Speed By Starre Vartan Writer Columbia University Syracuse University Starre Vartan has been an environmental and science journalist for 15-plus years. She founded an award-winning eco-website and wrote a book on living green. our editorial process Starre Vartan Updated September 25, 2018 Denise Mueller-Korenek broke the previous land-speed record for a paced bicycle at the Bonneville Salt Flats. (Photo: WSJ Video Screen Capture) Share Twitter Pinterest Email Transportation Active Automotive Aviation Public Transportation Denise Mueller-Korenek, now 45, had been a 15-time national champion in bicycle racing when she was a teen, but she gave it up to raise three kids and run a business. In 2016, she broke the women's paced bicycle record and just this month, she just broke the previous men's record, set by Dutchman Fred Rompelberg in 1995, of 166.944 mph. She beat that handily with a top speed of 183.932 mph. Paced bike racing has been around since 1897 and involves using a vehicle (in this case a pace car), which stops air resistance in front of a cyclist. The vehicle doesn't pull the rider, but does prevent the natural pushback you feel when you ride a bike. Just imagine how much resistance you feel when you wave your hand out a car window going 70 mph — the pace car blocks all that. The whole point is to use the car's slipstream to enable the cyclist to attain top speeds. Of course there's a special bike involved in this type of racing, too. The reason there's a tow at the beginning is that it bike's lowest gear doesn't even work until it gets to 70 mph. But once she's going that fast, the cyclist is working on her own energy. It's estimated that Mueller-Korenek put out about 700 watts of power to reach her record-breaking speed. (For comparison, it takes about 100 watts of power to cycle 15 mph on level ground; the average fit cyclist puts out about 300 watts of power at top speed.) The higher the speed, the more potential for serious injury if something goes wrong. This isn't just about pushing hard on the pedals to get top mph, it's also about maintaining perfect form and precision while pushing hard, so you don't make a tiny mistake that could send you tumbling. According to CNN, "Instead of traditional cycling clothes, Mueller-Korenek wore an eight-pound leather and kevlar suit to protect her in case of a fall and a motorcycle helmet to keep the salt out of her eyes. If she didn't pedal hard enough to stay in the race car's slipstream, she risked being catapulted backward by the wind." This is a dangerous sport. According to "Hearts of Lions: The Story of American Bicycle Racing," a 1988 book by Peter Nye, the history of the sport is littered with broken bones, and even deaths, especially since in the past, bike tires were more likely to burst at high speeds. "Bobby Walthour collected an impressive (or dismaying) inventory of injuries over his career: 28 fractures of the right collarbone, 18 of the left, 32 broken ribs, and 60 stitches to his face and head. Once, according to family history, he was given up for dead in Paris and taken to a morgue, where he regained consciousness on the slab." Mueller-Korenek reached her top speed between miles 4 and 5 at the Bonneville Salt Flats. "I think we broke the limit of what we were supposed to do," she said in a Facebook video on her page, Project Speed. She credits her pace car driver, Shea Holbrook, with working with her so well, especially on the most dangerous part of the ride, which is the slowdown. "I share this with Shea," Mueller-Korenek said. "It takes a team to do this. That's for sure. And she had to believe in the fact of doing this, of putting my life in her hands." Like any great athlete, Mueller-Korenek couldn't have broken this record without a team.