On a dark, rainy night in the mountains of Colorado — the kind that knocks out cell phone service and turns trails to mud — a lone figure bumped over roots and bushes, carving a new path through the underbrush. Suddenly, a cliff. “I thought maybe I could get close and just kind of bunny hop it,” Jake O’Connor remembered, his wheelchair rocking slightly back as he demonstrated the motion with his hands. Instead of the gentle landing he was hoping for, the back two wheels of the three-wheeled bike catapulted over his head. The entire thing slammed down hard into his back. Luckily, he was okay, thanks to a backpack that cushioned him from the impact. But the bike? “I thought the bike was destroyed for sure,” he said, shaking his head. It wouldn’t have been the first time he’d destroyed a mountain bike. But it would have been the first time he totaled one that he’d made with his own hands. In fact, his frustration with constantly breaking bikes is what first drove him to design a better model. Drawing on his background as a construction worker, O’Connor approached a local welder in Crested Butte, Colorado with a design for a sturdier frame to survive tough rides. The design gradually evolved to include practical adaptations: carbon fiber foot-holders to withstand the intense high-altitude UV rays; hefty tires for better off-road capability. As more and more people started asking for bikes, ReActive Adaptations, O’Connor’s company specializing in handbuilt, customized adaptive cycles, emerged. Four years later, his bikes have made it all over the world, used by everyone from the first person to handcycle over the Alps to a quadriplegic father who loves to hit the mountain for long trail rides with his son. “We have an ongoing relationship with our clients,” explained Dan Klim, a recent graduate in mechanical engineering who functions as the head mechanic and assembles the bikes. “I love working with them because we’re making dreams a reality.” Most clients are sick of not being able to get out, he said, and eager for the chance to re-learn how to ride a bike. Each bike is customized to the individual’s abilities and desires. ReActive Adaptations also builds bikes for participants in programs at the Adaptive Sports Center, a nonprofit organization in the town of Mt. Crested Butte that provides outdoor adventure activities for people with disabilities. Sylvie Fadrhonc, a physician assistant who lives in Park City, Utah and has a spinal cord injury, appreciates the unique engineering that makes the bikes so efficient, from the rear suspension to the adjustable chest pad for steering. “I can go anywhere on this thing,” she said, explaining how she enjoys riding trails while her partner hikes. “I’m not restricted to just the bike paths; I can go off the pavement and into the backcountry. It’s independence and liberty.” The custom modifications are endless and imaginative, keeping O’Connor and Klim creatively brainstorming new ways to adapt the bikes to the various needs they encounter. For example, one beautiful bike with a deep purple frame and golden spokes belongs to a woman who loves to strap her wheelchair to the back and go for long camping trips deep in the backcountry. O’Connor added huge, hefty tires to enable off-road excursions. Another particularly involved invention was a brake system that requires just a flick of the wrists. O’Connor asked a quadriplegic friend to do some practical testing — i.e., intense mountain-biking — for a month before they refined the design to its final form. “Sometimes you just have to go out and try to destroy it,” he said. These days, that’s much harder to do.