There should be a movie about Paralympic triathlete Krige Schabort. As a kid growing up in Cape Town, South Africa, he had almost no interest in long-distance racing. He ran in high school, but begrudgingly.

"I never really enjoyed it much," Schabort says. "There was some pressure from my parents and the teachers because there was talent there, but I didn't want to exploit it. I wanted to surf more. Surf and play rugby."

Schabort still surfs, but his world changed nearly 30 years ago. While serving in the South African army, a bomb exploded just six feet away from him. He was incredibly lucky to survive the blast, but he also lost both his legs. The "accident," as Schabort describes it, gave rise to a career as a world-class athlete.

Since then, the six-time Paralympian has medaled twice in the marathon, won gold and silver medals at the marathon world championships, broken an Ironman world record, competed for both South Africa and the US in the games, and won an Espy.

He's also been busy kicking Father Time's ass; This past weekend, a day after his 53rd birthday, he placed fifth in the first-ever paratriathlon event in the Paralympic Games in Rio. The guy who took gold, Jetze Plat from the Netherlands, was 25 years old. The average age of the other athletes was 36.

"My competition was on its A game, and that's one thing you can't control," Schabort says. "Those young guys are fast, I'm telling you. But I'm a guy who goes with experience. That's my one advantage."

Bob Croslin for WIRED

That experience includes the variety of vehicles he's ridden in high-level competition. Schabort started with wheelchair racing in the late 1980s. Then he began cross-training on a handbike, long before the triathlon was a Paralympic event.

Riders lay low and parallel to the ground, as if they're driving a hand-cranked luge.

In the relatively short amount of time Schabort has been riding handcycles, the bikes have undergone a radical transformation. Not long ago, steel and aluminum handbikes were the norm. About eight years ago, a company called Carbonbike came out with its first carbon-fiber hand-bike design. Now, all serious competitors are switching to carbon-framed bikes from that company and its competitors.

"At the highest levels, it's chaos right now," says Chris Peterson, president and co-owner of Carbonbike USA. "People are changing bikes, and in the last 12 months there's been a big change."

Schabort was one of those recent converts to carbon fiber. This year was the first in which Schabort rode Carbonbike's newest bike, the REVO-X, in major competitions: The ITU World Triathlon in Besançon, France; the world championships in Rotterdam; and the 2016 Paralympic Games in Rio.

Cranks and other parts in Peterson's workshop Bob Croslin for WIRED

They may be "bikes," but the vehicles used in the 20-kilometer stretch of the paratriathlon are nothing like a traditional racing cycle in terms of ergonomics, operation, and shock-resistance. For one thing, they're all front-wheel drive: The rider operates the pedals with his or her hands, in a push-pull rowing motion with the cranks set even at one another. Riders lay low and parallel to the ground, as if they're driving a hand-cranked luge. Compared to a traditional bicycle, there's much more friction involved. A rider's back, neck, and head are in constant contact with the bike.

After years of competing on aluminum-framed bikes, Schabort noticed the advantages of a carbon-fiber frame immediately.

"A lot of companies come into it, overdesign and make it too heavy," Schabort says. "Rotterdam is an example, there was like 16 turns in each lap, and we did four laps. That was continuous exercise, and every time you have to turn it wears on your speed. It's just that much easier to get back on speed when you're carrying a few pounds less."

Carbon fiber is famously light and strong, and it lends itself to more intricate sculpting than metal. Peterson compares it to shaping a candle: With an expert mold-maker and the right properties, bike-makers can do things that would be impossible with aluminum or steel.

"You can lay the carbon into the mold at different angles, make it thicker here and thinner there," Peterson says. There's material that's made to be stiff in one direction, and material that's stiff in multiple directions. "You can shape it in practically any way you can imagine."

Despite its stiffness, carbon fiber also absorbs vibration better than metal. Schabort says that's really important when you're dealing with full-body bumps over the course of a ride. He says he was sold on the bike when, during an early road test, he went over a rumble strip and the bike practically glided over it. It was a much softer ride compared to an aluminum bike, and rough roads didn't slow the bike down as much.

Chris Peterson of Carbonbike USA Bob Croslin for WIRED

One of the most important design elements is the REVO-X's unique front fork. Schabort says the area around the crank is much sturdier than any aluminum bike he's used, and the flex of an aluminum bike translates to lost energy. Peterson says the low-slung scoop element that distinguishes his fork design was a late addition. Early this year, he started thinking of ways to make the front of the bike lighter, a significant challenge with a hand bike.

"The front fork on a traditional bicycle has nothing really on it," Peterson says. "The front fork on a handcycle has everything on it. It has the cranks, it has the shifting, it's basically the entire bicycle on the front of this thing that you're sitting on... To do something as streamlined with aluminum or steel, it would weigh twice as much to make it stiffer and stronger."

By taking out extra material and beefing up the REVO-X's low-riding front fork, Peterson says he was able to shave off weight and make the bike more aerodynamic. But there was a nice side perk: Without as much material up front, it improved the riders' view of the road.

To get a better feel for the bike and potential areas of improvement, Peterson, who is able-bodied, says he rides a handbike six days a week. He also surrounds himself with world-class athletes like Schabort, who provide him with feedback on potential improvements. That's been the case since he started making performance wheelchairs in 1987.

Bob Croslin for WIRED

"George Murray won the Boston Marathon in a wheelchair. We ended up going into business," Peterson says. "I worked with him, and there was a lot of, 'Let's try this,' and we just kept trying to improve things. I've drawn out way more bad stuff than I've made good stuff, but you have to try things."

Nearly 30 years later, that spirit of trial-and-error has resulted in one of the coolest vehicles out there, period. But carbon fiber is pricey: A REVO-X with standard brakes and wheels runs about $10,000. With the add-ons that most top-level athletes use—carbon wheels, electronic shifting, a power meter built into the cranks—we're talking 18 grand. In sports technology, state-of-the-art is never cheap.