Two cyclists pedaled past Paul Bunyan Snowmobile Clubhouse in Bangor and onto the groomed ATV trails. Snow crunching under their tires, they climbed the hill and disappeared into an evergreen forest, leaving behind the faintest of tracks.

The couple — Craig MacDonald and Sarah Hannah of Bangor — were riding fat-tire bikes, commonly known as “fat bikes,” designed to tackle soft terrain, such as snow and sand.

“Mostly it’s the tires that make a fat bike a fat bike. The bigger the tire, the more float you get on a softer surface,” said MacDonald, the vice president of the Penobscot Region chapter of the New England Mountain Bike Association, or NEMBA.

McDonald purchased his first fat bike two years ago. This winter, he introduced his girlfriend Hannah to the sport. Already hooked, she’s training to compete at the first-ever Sugarloaf Fat Tire Festival, April 3 to 5, in Carrabassett Valley.

The three-day event will feature the Sugarloaf Fat Tire Downhill Race, as well as free fat bike demos, guided daytime and nighttime rides, a fat bike raffle; a season kickoff party for the Carrabassett Region New England Mountain Bike Association; and a guided ride to lunch at Stratton Brook Hut, an alpine lodge on the Maine Huts and Trails system.

“It’s really designed around people who haven’t tried (fat biking) yet to come and try it and check out these people who are already doing it and are accomplished at it and doing something extraordinary — climbing up Boardwalk and coming down Sidewinder, the banked slalom course,” said David Hughes, board member of the Carrabassett Region chapter of NEMBA and an organizer of the event.

A growing community

In the past few years, fat tire biking has gained popularity in Maine, mirroring a nationwide trend.

“People are starting to ride fat bikes a lot more around here,” said Jim Rose, owner of Rose’s Bike in Orono. He began offering fat bikes at his shop a couple years ago when he realized that the sport was growing.

Those looking to get into fat biking can simply look to their local NEMBA chapter, of which there are six in Maine: Bethel Area, Carrabassett Region, Central Maine, Greater Portland, Midcoast Maine and Penobscot Region. Another great resource is the Bicycle Coalition of Maine, a group devoted to expanding cycling opportunities in the state.

“The growth of fat biking is tied directly to the growth of mountain biking,” said Hughes. “They’re really one sport, just one’s done in the winter and one’s done in the summer.”

The short history of fat bikes begins in the 1980s, when mountain bikes first became a common commodity at outfitters and sports shops, according to a 2014 story published by the Adventure Cycling Association. During that time, people began modifying mountain bikes to ride on sand and snow. And in 1987, the first Iditabike event — a 200-mile bike race in the Alaskan backcountry in winter — was held.

It wasn’t until 2005, however, that fat bikes became available to the general public when Surly, a well-known bicycle company, released the Pugsley, a fat bike with 3.7-inch wide tires. In the following years, dozens of companies followed suit, offering their own versions of fat bikes.

It’s not just the tires

Fat bike tires range in size from 3.5 to 4.5 inches wide, while a standard mountain bike has much narrower tires, typically 2 to 2.5 inches wide. But that’s not the only difference between a fat bike and a mountain bike.

“Some people think you can take a tire like this and put it on a regular mountain bike,” said MacDonald, placing a gloved hand on the snowy 4-inch wide tire of his fat bike. “You can’t do that. The frame needs to accommodate the size of the tire.”

As the number of companies making fat bikes has increased, the price range and quality of the bikes has expanded. You can currently dish out $4,595 for an Aluboo Bamboo fat bike or pay just $200 for the simple Mongoose fat bike at Walmart.

Regardless of the quality of your fat bike, there’s one thing you need to know: while mountain bike tires have a tire pressure of 30 to 50 psi, fat tires should be about 8 psi to handle soft snow. The lower tire pressure means more surface contact, better traction, better floatation and more cushion. As the terrain hardens up, fat bikers usually will increase their tire pressure.

“The tire pressure is really important,” MacDonald said. “You may actually change your tire pressure throughout a ride because you’ll encounter different conditions.”

“Trail conditions play a big part in where you can and can’t ride,” Hannah said.

Sharing the trails

To prepare for the Sugarloaf race, Hannah has been riding on a variety of Bangor-area trails, including the trails of the Rolland F. Perry City Forest in Bangor, multi-use trails in Orono, the Perch Pond bike trails in Dedham and local snowmobile trails.

Good fat biking routes are surfaced with smooth packed snow, making snowmobile trails an ideal fit. Typically, the colder the conditions, the better. Sticky snow and mud is difficult to ride through, even with fat tires.

“Around here we mostly rely on snowmobile trails,” Hannah said. “We’re trying to expand in this area, getting in with snowmobile clubs, making our sport known and kind of working with them for us to be able to use their trails.”

On March 17, MacDonald and Hannah headed out on the Bangor snowmobile trails in the morning, when the day was coldest and the riding conditions best. They floated on top of the packed snow as they emerged from the forest and rode along the chain-link fence of the Bangor International Airport.

“I really enjoy going fast like a little kid,” MacDonald said. “That’s the thing about biking. You can be an adult, but it’ll make you feel like a kid again … Some of the most spectacular crashes I’ve ever had have been on a fat bike.”

For that reason, MacDonald suggests that anyone trying fat biking wear a helmet. From experience, he knows how quickly a patch of ice can cause a rider to fly off trail and into the trees.

Past the airport, the couple worked their way up a long hill, something they’d both enjoy zipping down on the way back.

“It works a lot of muscles you don’t think it would,” Hannah said. “It brought my fitness to another level.”

“Biking is an all-over workout. But really, it’s also a great workout for your mind — a stress reliever,” MacDonald said. “In the winter time, when I go fat biking, that’s my yoga.”

Hannah and McDonald regularly attend group fat bike rides organized by the Penobscot Region chapter of NEMBA and area bike shops. While they usually visit trails in the Bangor area, they sometimes travel to places such as Sugarloaf Outdoor Center, home to a vast network of multi-use trails that attract cyclists year round.

“I think a lot of people believe they can’t do it, and you can,” Hannah said. “It’s something you can get out to do. It won’t be easy, there’s no part about it that’s easy, but you can do it.”