As an adventure travel writer, I’ve experienced mountain and road biking in a few iconic destinations in the United States and overseas. One of the greatest bike culture impressions left on me was in Amsterdam, Netherlands, where 320 miles of paved cycle-designated roads are chock-full of bikes: One-quarter of the country’s population cycles daily. And an additional two million electric bikes navigate the road. The city’s well-integrated cycling paths parallel the roads and tram lines with their own painted lanes and cycle traffic lights. Compared to the bike-friendly cities of the United States, that level of urban bicycle infrastructure is incredible to experience.

When I think about sustainability with regards to biking, I often think about the lifestyle and resources available to local Hollanders. A significant portion of the population gets daily exercise while commuting by bike and simultaneously less vehicle emissions are increasing global warming. With this glorified perspective of bikes, I’d not yet considered how the manufacturing of bikes might add an environmental toll that should warrant a pause. I wanted to learn more about the materials that are used to create our mountain bikes.

When I’m not covering adventure travel stories, I’m an outdoor industry news reporter. As a journalist, I was able to reach out to ten of the country’s top mountain bike companies. After chatting with these founders, owners, vice presidents of product development, and managers, these are the most progressive changes taking place in the industry today.

Revel Bikes: Solid Bikes and Sustainability

Revel Bikes Founder Adam Miller has always been obsessed with bike manufacturing. As a pre-teen, Miller bought used bikes from garage sales and eBay to resell the parts or build his own Frankenstein-fashioned two-wheelers. Over the years, Miller worked at a local fat bike shop then collegiately raced mountain bikes.

“I grew up racing road, cross-country mountain bikes, and cyclo-cross. I got really into making bikes, because I like making stuff. I learned a lot about composites and carbon fiber. There is a ton of cool stuff you can do with composite materials—and the bike industry was not pushing those limits, I thought,” says Miller, who launched his first bike company, Borealis Fat Bikes, during college, followed by Why Cycles and then Revel Bikes, in 2019. The brand quickly received accolades including the Best Mountain Bike of 2020, awarded by Outside Magazine, as well as honorable mentions from VeloNews and BikeRumor for best bike of 2019.

But Miller didn’t really tell me about those awards. He was most excited to chat about Revel’s sustainability efforts. “We’re pushing the limits on sustainability, and that leads us to the most exciting product launch that we've done,” he says.

Fusion-Fiber: An Alternative to Traditional Carbon

Enter Revel RW30 Wheels, which are “one-hundred percent made in America, and based on a whole new type of composite. They are not made out of traditional carbon fiber,” explains Miller. In bike anatomy, each wheel has a rim: the circular, outermost material that holds the tire. A tire is a removable case that is mounted around each wheel. Tires are made out of firm rubber and provide traction. A variety of wheel and tire materials and sizes exist, which can each perform slightly differently for an array of terrain and rider preference.

But the most important thing to pay attention to isn’t the actual wheel. It’s that the wheel is made out of materials that are not traditional carbon.

Carbon is super light, very strong, stiff, and is used to make bike frames. It’s the prized material among many manufacturers when it comes to bike performance and rider preference. However, carbon development is irrefutably negative for the planet. Carbon bike frames contain toxic resins, carbon fiber is extremely difficult to recycle and nonbiodegradable, and overseas factories—where 99% of bikes sold in the U.S. are made—often throw the excess trim into the ocean, reports Outside Magazine. Not to mention, those materials are handled indoors by humans with no universal health safety standards.

The essence of why carbon is loved is also what makes it so damaging to human health and the environment. Carbon is tenacious due to the epoxy resin that’s used to bond the carbon fibers together. But Revel’s new material, Fusion-Fiber, eliminates that epoxy. “We partnered with a manufacturer that makes parts for Boeing, Airbus, and HondaJet—a crazy high-level of manufacturing—that’s four hours away from Carbondale, CO. They developed this material and we were the first company to use it in bicycles. It gets rid of all of the epoxy, which has all of the bad stuff in normal carbon. The epoxy is replaced with a nylon polymer,” explains Miller.

The end product weighs the same as carbon but is stronger and recyclable. Plus, it’s more cost-effective to make. Miller adds, “Epoxy is brittle. Instead, this wheel is really quiet, so when you hit a rock, it dampens.”

What the Industry Says

So far, the industry agrees with Miller’s perspective. PinkBike published a first impression of the wheel: “Mounting up tires was straight forward, and I had zero issues airing up with a standard floor pump. In my time on the trail, I can confirm that they deliver in terms of stiffness and compliance, and I've had zero issues with anything otherwise. The wheels do seem to do a good job of damping trail chatter, especially at high speeds, and there is something unique about the way they ride compared to other carbon wheels that I've been on. Long-term use is yet to be seen, but we'll provide an update once I put a lot more miles on them,” said journalist Daniel Sapp.

And Worldwide Cyclery reported, “It's certainly one of the lightest 29mm internal carbon rims on the market; it's only 470g for a 29-inch carbon rim. Compare that to an Enve M730 with the rim strip, which weighs about 110g more at 580g. While in testing, Revel was able to retain as much strength as any comparable wheel.”

An Exclusive Partnership: CSS Composites

To develop Fusion-Fiber, Revel has an exclusive manufacturing partnership with CSS Composites, a company co-founded by James Seear and Joe Stanish. Miller and Stanish met a decade ago, when Stanish was the VP of Operations at ENVE Composites. “I feel really lucky that we're at the forefront of this new material. We're using it in bikes, but other companies are using types of thermoplastic (editor’s note: that’s another word for nylon polymer) composites, too, like the Airbus A350 XWB wing. A new [GMC] truck bed uses a similar type of thermoplastic composite, too,” says Miller. (Check out GMC’s strength tests against the CarbonPro truck bed in this commercial—it’s worth a watch.)

So, Revel’s bike materials are made out of the same materials as an airplane? Sort of.

“Carbon fiber is a bunch of threads of material. Traditional carbon fiber is dried, impregnated with epoxy resin, and those fibers are woven together. Then, they go into an oven to cook and cure to become solid. We use the same original carbon fibers, but instead of traditional epoxy use, we use a nylon polymer,” explains Miller. Then, the difference with the automobile, aerospace, and wind turbine manufacturers that are also tapped into this manufacturing process is that they need “a type of nylon adhering agent that has a higher temperature range. Our bikes aren't being used in negative 80 to 300 degrees Fahrenheit. That's the step where the manufacturing process changes and a different factory handles it. And our particular nylon polymer blend is proprietary for what we're using it for in the bike industry,” he says.

No One Else Is Doing This?

Revel’s Fusion-Fiber actually sounds similar to what Guerrilla Gravity recently introduced: Revved Carbon, a patent-pending carbon fiber blend that replaces traditional carbon fiber used in the bike industry via a new made-in-America manufacturing process. According to Guerrilla Gravity, this new material is “environmentally-responsible” with many green advantages. However, the brand hasn’t yet disclosed how exactly their secret ingredients differ from traditional carbon fiber. In addition to the material, the process largely uses automated methods rather than humans.

“We developed a new carbon fiber manufacturing process, to be specific. The type of carbon fiber is definitely new to the mountain biking industry, and that’s where the impact-resistance comes from. It was driven by the idea, ‘Hey, we want to keep making our bikes here, but we also want to make carbon fiber bikes, and we want to make them more durable. How do we solve that problem?’” says Guerrilla Gravity Founder Will Montague.

Revved Carbon is used to build the brand’s bike frames. Matt Giaraffa, the chief engineer at Guerrilla Gravity, took inspiration from the aerospace industry, namely Boeing, reports Bike Magazine (which is also a similar parallel to Revel). Several years of research and development was needed to nail down the carbon blend, which included testing various fiber orientations and types, according to PinkBike.

“We essentially developed a new manufacturing process that allows us to make our bikes here in the U.S. for a comparative price point to what they could be made for in Asia, so that allows you to shorten the supply chain and lower your carbon footprint. Allows you to iterate quicker. Allows you to reduce inventory. And the resin that we use is also more impact-resistant, so it also improves the product performance, as well,” says Montague. Compared to traditional carbon, Revved Carbon is more impact resistant, easier and cheaper to recycle, and safer for humans to handle, according to Guerrilla Gravity.

What does the industry say, so far? In an examination of the Guerrilla Gravity Trail Pistol bike, the frame was anecdotally stiffer and more supportive than the Transition Smuggler (another carbon frame bike), shared Blister Review: “The Smuggler had some moderately significant flex through corners, whereas the Trail Pistol was tracking a bit straighter.” According to the review, the Smuggler was better at ironing out mid-sized bumps, more supple, and maintained better traction through corners. But the Trail Pistol handled big hits more gracefully, as well as pumping and popping off of rollers. Enduro Mountainbike Magazine echoed a similar sentiment, reporting that the frame of the Guerrilla Gravity Gnarvana is not the most supple.

Guerilla Gravity also mentions on their website that with the creation of Revved Carbon they sought to manufacture a mountain bike that blends the best qualities of aluminum, steel, and carbon--so maybe the blend includes all three materials? The Boeing 787 Dreamliner is made out of “woven mats of carbon that are embedded in plastic,” reports BBC. According to Boeing, the airframe is nearly half carbon fiber reinforced plastic, and the remaining materials are mostly steel, titanium, aluminum. Hopefully after that patent is processed we can all learn more!

Revel: Stoked on Recyclable Material

Beyond the actual manufacturing of Revel’s Fusion-Fiber, Miller is stoked about the holistic program that the brand rolled out. “If someone breaks their wheel, we pay to ship it back to recycle it. And we recycle every single bit of scrap from the manufacturing process. And we just made our first-ever product out of the recycled composite material: a tire lever,” he says.

“Now, the goal is to make as much as we can with this new material. I think that it will change the whole face of how bikes are manufactured,” says Miller. It seems the only factor slowing down Miller’s goal is the overall cost of research and development. But with time, Miller intends to incorporate the sustainable material into as many bike parts as possible.

In his perspective, “None of what we're doing is environmentally friendly: we are manufacturing products that no one needs but are cool toys to explore nature. If we're going to make stuff, doing it in a more environmentally friendly way is the best thing we can do.”

At the moment, both of these manufacturing processes and materials are only accessible to the two brands that pioneered them, which is fair. But it would be amazing to one day see a full disclosure of Guerilla Gravity’s carbon fiber materials—I’m so curious to evaluate their sustainability. And it would be incredible to see more mountain bike companies—if not all—invest in environmentally-friendly carbon fiber for mountain bikes right here on U.S. soil.