Fat Bike vs. Mountain Bike: What’s the Difference?

Deciding between a fat bike and a regular mountain bike isnʼt as simple as choosing between a mountain bike and a road bike. 

After all, both mountain bikes and fat bikes have been engineered with a similar objective in mind—off-road biking. Plus, they have similar styles as well.

Before deciding on a model, you need to be aware of your expectations from the bike. Additionally, you need to figure out your budget and identify the type of landscape youʼre most likely to be mountain biking on. 

Finally, ask yourself how often you intend to ride. Are you planning to bike all year round or only for short periods? 

You’ll only be able to make an educated purchase (investment) after discovering all the answers to the aforementioned questions.

How Do Fat Bikes Different From Mountain Bikes?

The major difference between a mountain bike and a fat bike is the tire size (width of the tires). As you may have deduced, fat bike tires are much wider than mountain bike ones.

On average, youʼll find that fat bike tires measure anywhere between 3.8- to 5.2-inches wide. On the other hand, standard mountain bikes come with tires in the 1.9- to 2.6-tire width range.

While we are talking about tires, letʼs also discuss the pressure the tires operate at. While most fat tires are capable of running at incredibly low pressure of 5–14 psi, most mountain bike tires canʼt run below 22–25 psi. 

The thing is—a fat bike tire is much more voluminous than its counterpart and, as such, doesnʼt bottom out and hit the rim even when you hit an obstacle.

Since fat bikes have to accommodate larger, wider tires, they have wider rims too. Youʼll see that most fat bike rims measure 65mm or wider. 

Comparatively, mountain bikes have narrower rims, not exceeding the 30mm-width range.

Thereʼs also a stark difference between fat bike frames and mountain bike frames. The fork arms, chainstays, and seatstays on fat bikes are made much wider by manufacturers to accommodate the wide tires. 

As a result, youʼll also notice that the hub spacing is wider on a fat-tire bike than on mountain bikes. 

The extra wide rear hub spacing, subsequently, results in a wider crank spindle and bottom bracket, keeping the chain ring further from the frame and preventing the chain from operating at an unusual angle.  

In essence, you could say that almost everything on a fat-tire bike is wider, but are fat bikes fast and are fat bikes easier to ride? You may also be wondering – are fat bikes good for beginners?

Well, letʼs get to the juicy bit to find out. We’ll also look at the pros and cons of both fat bikes and mountain bikes. 

Let’s finally settle the fat bike vs. mountain bike debate. 

Fat Bike Pros

Helps you ride in muddy, snowy, and loose terrain

Most fat-tire bikes make it possible for you to bike in deep snow, mud, and loose sand. Instead of digging in, they tend to float across the top on such surfaces. 

You see, fat, huge tires evenly distribute the weight of the rider, bike, and gear across more surface area so that the wide, fat tires apply less pressure on the ground, thus, allowing the fat bike to float along without sinking in. 

This rollover feature is often called flotation. Fat bikes offer more traction on such surface areas too.

Facilitates a comfortable ride

As I mentioned earlier, most fat bike tires operate at extremely low air pressure. As a result, they are able to absorb vibrations and shock better on off-road trails, facilitating a comfortable ride in even the most treacherous and rugged terrain.

Offers outstanding grip/traction

The larger, wider fat tires are able to make more contact with the ground, increasing friction between the ground and tire. As a result, the wide tires can offer better traction and grip. 

The increased traction is particularly important when negotiating slippery terrain.

Versatile enough all year round (all-terrain bikes)

You can ride on a fat-tire bike all year round, irrespective of the weather conditions. They operate fine on smooth surfaces, slippery terrain, and loose trails. 

What more could you ask for from a bike? 

Plus, a fat bike can be adjusted to fit narrower tires. If that doesnʼt showcase versatility, I donʼt know what will.

Fat-tire bikes can help you burn more calories

Compared to mountain bikes, fat-tire bikes have larger tires which means that a fat bike requires you to burn more energy to maneuver it and get rolling. So, in essence, you stand to burn more calories mountain biking on a fat bike.

Fat Bike Cons

Of course, like everything in the world, fat bikes arenʼt perfect either. They do come with their fair share of disadvantages. 

Letʼs go through some of them.

Difficult to find replacement parts

It is a well-known fact that fat bikes mostly use non-standard hubs, disc brakes, rims, tires, cranks, and bottom brackets. Since they are non-standard, they are quite uncommon and difficult to find. 

As a result, replacement parts of fat bikes arenʼt very accessible.

Imagine how inconvenient itʼd be if you were biking in a remote region and you find yourself with a broken or cracked rim. Youʼd probably need to travel to the capital to find its replacement.

Fat bike tires create more rolling resistance

Wide tires, almost as big as car tires, create plenty of friction with the ground. As a result, they are slow-moving and require a lot of energy to get going. 

Fat biking isnʼt suitable for you if you donʼt want to expend a lot of energy.

Fat bikes are heavier than mountain bikes

Since fat bikes have wider tires, wheels, rims, and almost everything else, they carry more material than a mountain bicycle, making them quite heavy. To put things into perspective, a fat bike can weigh around 33–40 pounds whereas a traditional mountain bike typically weighs in around the 22–30-pound range.

The heavier a bike is, the tougher it is to navigate/maneuver through technical trails and steep hills. 

Fat bikes donʼt make you a better rider

A fat bike, owing to its large, knobby tires, is capable of going over any type of obstacle including dips, branches, rocks, roots, and sandy patches making them easier to ride. As a result, you wonʼt be able to develop your technical skills as a rider as you wonʼt need to avoid or navigate obstacles on the trail. 

In layman’s terms, riding a fat bike allows you to bike on the mountains more easily.

Mountain Bike Pros

Replacement parts are easier to find

Mountain bikes are found and sold in every corner of the world. As a result, you can take your bike with you even in the remotest of areas without having to worry about finding replacement parts if you damage your disc brakes, for example.

They are more efficient

Downhill bikes donʼt create as much rolling resistance as fat bikes. As a result, they travel faster and are much easier to ride on. 

Even keeping the bike at a specific high speed doesnʼt require much energy as most mountain bikes cruise. On the other hand, coasting on a fat-tire bike is next to impossible.

They are lighter due to their lightweight and flexible frames

Compared to fat bikes, on mountain bikes, everything is narrower—think rims, tires, and mountain bike wheels. Since mountain bikes require less material to make, they are considerably lighter than most fat bikes. 

It also helps that they are mostly made of lightweight carbon frames. A lighter bike goes faster, is more efficient, requires less muscle power, and is easier to maneuver too.

Mountain bikes are cheaper

Go for a downhill mountain bike if you donʼt want to spend a bomb on a bike. Mid-range mountain bike models cost anywhere between $1,000 to $1,800. 

Are fat bikes cheaper? No, youʼd need to spend an extra $500 to purchase a budget fat bike.

Mountain Bike Cons

Mountain bikes canʼt operate on sandy, snowy, and muddy trails

It is almost physically impossible for a person to ride through sandy, snowy, and muddy terrain on a standard mountain bike. Traditional mountain bikes also canʼt handle rough terrain covered with large rocks.

However, some bikes come with dual disc brakes which offer more safety when crossing slippery terrain.

Mountain bike rides arenʼt as comfortable to ride on as fat bikes

Mountain bikes donʼt offer as comfortable of a ride (smooth ride) as fat bikes for off-road riding. Since most mountain bicycle tires have less volume and operate at a higher tire pressure, they donʼt absorb shocks and vibrations as well as fat bikes. 

Granted, a high-spec mountain bike does come with a rear suspension fork to handle the bumps, but so does a fat bike.

Mountain bikes donʼt offer as much grip/traction as fat bikes

Since mountain bikes are designed for off-road mountain biking, they do offer an acceptable level of grip and traction, just not as much as fat bikes. 

Since mountain bike tires have narrower tires, they arenʼt able to form much contact with the ground, resulting in less friction, which ultimately leads to less grip/traction.

It requires technical riding skills

Though any Tom, Dick, or Harry can ride a mountain bike easily, it takes special skills for mountain bikers to go through technical, rocky terrain with minimum fuss. 

Comparatively, fat bikes can roll over any type of obstacle, including dips, branches, rocks, roots, and sandy patches, etc. So, even the most novice riders would be able to ride off-road and participate in extreme riding. 

Conclusion

Now that you know the pros and cons of both fat-tire biking and mountain biking, you can easily weigh your options and choose a bike model that suits your riding style and goes well with the terrain you’re likely to ride on the most.  

Finally, ask yourself, how often you intend to ride and where – are you planning to bike all year round or only for short periods? Once you’ve determined that, you can figure out if you want to run fat tires or thinner ones. 

Ultimately, when considering the pros and cons of a fat-tire bike vs. mountain bike tires, well, it really boils down to personal choice.