Fat bikes fill a unique niche in the cycling world. Aptly named (if a bit tongue-in-cheek), fat bikes are a sub- type of mountain bike named for the enormous tires they use. While traditional mountain bikes typically run tires between 2.0” and 2.3” in width, fat bikes tires typically start at a massive 4” wide, and grow from there. And these massive tires do more than just look cool. They actually provide extraordinary functionality, especially when put toward their intended use.
Fat biking exploded in popularity for a brief moment a few years ago. It seemed like every other customer that came into my shop was either expressly looking to buy a fat bike or was at least intrigued at the sight of what looked like a normal mountain bike in nearly all respects except for the huge tires beneath it. The massive enthusiasm that fat bikes generated was, unfortunately, quickly overshadowed by the advent of plus- sized mountain bikes not long after.
Plus bikes tried to essentially combine the best elements of traditional mountain bikes and fat bikes into a single trail-shredding machine that typically ran 3.0” tires. Plus bike received mixed reviews, with some riders immensely enjoying the added traction provided by the larger tires while others lamented the extra rotational weight. In any event, plus bikes may have caused fat bikes to fall off riders’ radar a bit, but make no mistake, they are still around, and fat bikes still very much have a place in any cyclist’s stable.
So what type of riding are fat bikes intended for? Well, the answer is somewhat mixed in the sense that riders can enjoy riding their fat bike pretty much anywhere they’d ride their traditional mountain bike. True, a fat bike’s huge tires may not be entirely necessary in terms of the traction required to ride a particular trail. But that doesn’t mean it can’t come in handy. The nearly unbreakable traction provided by a tire 4” wide or wider can allow riders to fly up steep climbs they otherwise may not be able to crest on a regular mountain bike. Indeed, the top times on some of the steepest, most technical climbs in my area were set by a local rider on a super-light fat bike, which goes to show that, like many bikes, fat bikes should be put into too small a box.
Despite their versatility, fat bikes are built to excel in a couple of areas in particular where traditional mountain bikes just can’t hold a candle. The first, and arguably foremost, area where fat bikes excel is in the snow. There is simply no question that a fat bike with a studded 5” tire is going to handle a snowy trail with ease, whereas a traditional mountain bike (and even a plus bike) will, at best, merely survive. And the difference becomes even more stark if the snow is fresh rather than packed. Traditional mountain bikes can usually at least handle snow-packed trails if the bike is equipped with burly trail tires. But when the snow gets deep, the traditional mountain bike’s relatively narrow tires will sink through the snow, whereas the fat bike’s massive tires will float on top of it.
The second area where fat bikes provide a manifest benefit over their skinnier counterparts is in the sand.
Drawing inspiration from the beach cruisers of olde, the floatation provided by a fat bike’s massive tires makes riding over sand much more enjoyable than slogging through on skinnier tires. What is more, fat bike tires use tread patterns very similar to those of other mountain bike tires. Thus, it’s easy to see how a knobby, aggressive tread pattern spread out over 4” or 5” is a total game-changer when it comes to riding through sand, not only on the beach, but also in places like Moab, Utah, revered for its countless miles of dusty, sandy desert trails.
Yes, fat bikes may not garner quite the interest that they did a few years ago, but they still very much have a place not only in our hearts, but in the world of cycling, also.
In this article, we’re going to take a look at a few of our favorite women’s fat bikes. As with our article on women’s gravel bikes, this one will also set out a few key factors to consider before purchasing a fat bike. Some of those considerations, such as frame material and drivetrain, are quite similar to the choices riders need to make before purchasing a gravel bike. But there are a couple of factors that are specific to fat bikes, therefore deserving special attention and consideration.
The Bikes
While fat bikes may not be as overtly popular as they once were, there is still a vibrant market for them, along with a dedicated base of cyclists that love fat biking. The bikes listed below are a few of our favorite women’s fat bikes on the market today.
Specialized Hellga
Specialized makes a bike for pretty much any type of riding you could image. So it should come as no surprise that they’ve waded into the fat bike game, too. Specialized’s women’s-specific fat bike is called the Hellga.
The Hellga’s defining feature is its remarkably low standover height of just 676mm. Featuring a dropped top tube not found on the men’s counterpart, the Fat Boy, the Hellga provides ample room for smaller riders to stand over the bike comfortably.
The Hellga is built around an M4 aluminum frame and fork, and it uses a Sram X5 10-speed double-ring drivetrain with 36/22 chainrings. Paired with an 11-36 cassette, this should provide plenty of range to get up even the slickest snowy climbs.
The Hellga rolls on 32h Stout rims laced to Stout disc hubs spaced at 190mm in the rear and 135mm in the front. This durable wheelset is wrapped in Specialized’s famous Ground Control tires in size 26×4.6. Each Hellga build is rounded out with a host of women’s-specific components ranging from Specialized’s Myth saddle to narrower handlebars than those found on the smallest men’s counterpart.
Framed Alaskan Carbon
Minnesota’s Framed Cycles is dedicated to the idea that riding a bike should be fun, and that it doesn’t need to be expensive. Given the Twin Cities are consistently rated some of the most bike-friendly cities to live in, it’s no surprise to learn that Framed’s passion for cycling shows through in every bike it produces.
Framed’s women’s-specific fat bike is called the Alaskan. This bike also features a steeply sloped top to provide for maximum standover clearance. The Alaskan is built around a carbon frame, saving some weight and offering better-pedaling efficiency than its aluminum counterparts. Paired with a carbon fork, the Alaskan is ready to take on the steepest climbs you can find. And if the downhills are what you really live for, Framed offers an Alaskan build with a Rock Shox Bluto suspension fork to really soak up the bumps.
Framed currently offers the Alaskan with either a Shimano Deore 1×10 or Sram NX Eagle 1×12 drivetrain. Riders will pay a bit of a premium for the 1×12 drivetrain, but the extra range is worth it in our opinion, especially considering the Alaskan comes stock with a 32T chainring.
The Alaskan rolls on 27.5” wheels wrapped in 3.8” tires. While this contact path is a bit narrower than that of other fat bikes, the larger wheels tend to roll over obstacles such as roots and rocks more efficiently than smaller wheels. Framed also offers riders the option of choosing carbon or aluminum rims, meaning the Alaskan can quickly turn into a lightweight ripper while still maintaining its essential character as a fat bike.
Borealis Flume
Borealis is a company dedicated to making fat bikes. Based in Colorado Springs, Colorado, Borealis knows a thing or two about making bikes for riding in the snow. As a dedicated fat bike manufacturer, Borealis offers a variety of fat bikes for riders to choose from. But the one that caught our eye is the Flume.
This bike, like the others that we’ve looked at, also offers a relatively low standover height, allowing smaller riders to remain comfortable while standing over their bike. Featuring an alloy frame and a variety of both rigid and suspension fork options, riders can put together pretty much any build they can imagine. Borealis’s website not only makes it easy to select each individual component that goes into the bike, but it also is perfectly transparent in how each component affects the weight and price of the complete bike.
In this vein, Borealis offers the Flume in five different Sram 1×12 buildouts, ranging from the functional and affordable NX Eagle kit to the super-trick Eagle AXS XX1 wireless electronic drivetrain. Borealis also offers riders a choice of hubs, spokes, and rims in all sizes, which means the Flume can run both 26×5” tires for the snowiest winter rides to 29×2.8” tires for speeding through singletrack in the summer, and everything in between. Leaving no detail forgotten, the Flume features three bottle cage mounts so riders can pack all the hydration they need for all-day excursions.
Because Borealis equips every Flume with parts the rider selects, price will vary from build to build. For this review, we spec’d out a Flume with a rigid carbon fork, alloy rims, and a mid-level Eagle XO drivetrain to arrive at a total price of $2,642 and a total weight of just 27.45 pounds.
The Buying Guide:
Fat bikes, as we mentioned, are a sub-set of mountain bike. As such, they share many characteristics with traditional mountain bikes like flat handlebars, disc brakes, wide-range gearing, and wide tires. Fat bikes just happen to take that last characteristic to the next level!
Frame material
There are two primary materials that fat bike frames are made from: aluminum and carbon fiber. Aluminum bikes are typically heavier than carbon bikes, but they’re also almost categorically less expensive. Thus, an aluminum fat bike is perfect for the rider getting into fat biking for the first time, while carbon bikes are great for riders seeking the ultimate performance out of their fat-tired machines.
Drivetrain and gearing
Another consideration that goes into any bike purchase is the type of drivetrain the rider wants to use. And while running the correct gearing is important on any bike, it deserves a special look here due to the unique terrain that fat bike riders often ride.
Again, as with gravel bikes, there are a variety of drivetrain options to choose from, including both
mechanical and electronic options. The first decision to make, accordingly, is whether you want to run a mechanical or electronic drivetrain. As with their road and gravel-oriented groupsets, Shimano’s electronic mountain bike groupset uses wires, while Sram’s is wireless.
The next decision you should be prepared to make is whether you want to run a single-ring or double-ring setup. However, because most mountain bikes now universally use single-ring drivetrains and wide-range cassettes, you may not need to make this decision at the time you purchase your fat bike. But if you’re absolutely set on running a double-ring setup, don’t worry. Although it may be a bit difficult to find a fat bike that comes equipped with a double-ring drivetrain, some fat bike frames are at least compatible with front derailleurs should the rider wish to change the bike’s setup sometime down the road. Moreover, single- ring drivetrains are very well-suited for mountain biking and likewise for fat biking.
That leads us into gearing considerations. Because fat bikes will typically use single-ring setups, the first decision to make is the size of your front chainring. Given that fat bikes excel on steep climbs and through loose terrain, speeds are typically a bit slower than on traditional mountain bikes. Thus, we’d recommend running either a 28T or 30T chainring, depending on the size of the largest cog in the cassette. This will help you say closer to the middle of your cassette at typical riding speeds, reducing drivetrain friction and chain wear while also ensuring you have plenty of range to make it up steep climbs.
Wheel and tire size
Although fat bikes’ quintessential characteristic is their massive tires, those tires come in lots of options. Many fat bikes, especially many women’s fat bikes, use 26” wheels, as they tend to fit more easily into smaller frames and accordingly allow for better frame geometry. Still, some fat bikes use 27.5” wheels and some even fit 29” wheels as well.
As we’ve already mentioned, fat bikes are designed to run tires between 4” and 5” wide. Many come stock with tires 4.5” to 4.8” wide, but it’s worth asking just how wide you can go. After all, if your plan is to ride your fat bike in the snow, you’ll likely at least want the option to run a 5” tire.
Q-factor
Q-factor is perhaps the single most important consideration specific to fat bikes. According to Otso Cycles, an industry leader in the fat bike arena, a bike’s Q-factor is “a function of crank spindle length, bottom bracket width/type, and chainstay specifications to ensure proper chain-line relative to tire dimensions and rear hub spacing.” In other words, Q-factor essentially refers to the distance between the pedals when they’re installed on the crankarms. Otso explains, because Q-factor “affects how far apart the pedals are,” it “in turn affects the biomechanics of pedaling and the handling of the bike.” [source: https://otsocycles.com/pages/q- factor-and-the-voytek].
Because fat bike frames must have room to clear enormous tires, they necessarily must use wider bottom brackets than traditional mountain bikes. This ultimately causes the pedals on the crankset to sit farther apart. This isn’t necessarily a problem, but if a bike’s Q-factor is too wide for a particular rider, it can feel awkward to pedal or even lead to biomechanical injury due to improper muscle recruitment and lower body alignment.
All this is to say that it’s important to test ride a variety of fat bikes before taking one home.
Final thoughts
Fat biking puts an exciting twist on mountain biking and allows riders to not just continue riding outside through even the harshest winters, but to look forward to it.
Fat bikes’ massive tires open up lines and trails that would otherwise be difficult or impossible to access on a traditional mountain bike, providing for some epic adventures along the way. So if you live in a place with sandy trails or snowy winters, or if you’re just looking for a way to shake up your normal mountain biking routine, we highly suggest heading down to your local bike shop and taking a few fat bikes for a spin.
