Fat Bikes

If you’ve looked around the mountain bike world at all, you’ve almost certainly noticed fat bikes. There are plenty of them out there, and they are instantly recognizable: the balloon-sized tires stand out in any company! Fat bikes have gained a reputation for stability, easy riding, and fun, and they are an ideal choice for less experienced mountain bikers. But what is a fat bike, why should you consider one, and what should you look for if you want to buy one? Let’s break down the characteristics, advantages, and disadvantages of the big-tired bike, and take a look at what you can expect to find at different price points.

What is a Fat Bike?

A fat bike is usually defined as a bicycle using tires of 3.8” width or larger, ranging up to 5” wide. These oversized tires are usually mounted on rims 2.16” wide or wider. That’s twice the size of a standard mountain bike tire or more. The tires can seem almost freakishly large at first glance, and some riders never get used to the look, but there is a purpose to having all that rubber under you. The width of the tires provides stability and cushioning. The tire size allows you to run on very low tire pressures, keeping the tires squishy and allowing them to absorb bumps and grip the terrain under the tire.

The tires define a fat bike, but there are other typical fat bike characteristics, most of which are related to the tire size. Here are a few things you can expect to find on a fat bike:

  • Rigid frames and forks – Most mountain bikes have a suspension fork up front and many have rear suspension as well. Fat bikes often drop the suspension, relying on the tires to cushion the ride. Some fat bikes use short-travel suspension forks specifically designed for fat bikes (conventional suspension forks won’t have enough tire clearance), but most retain the rigid fork. Suspension is a major contributor to the cost of a mountain bike, which gives rigid fat bikes a substantial cost advantage.
  • 26” wheels -Almost all conventional mountain bikes use either 29” or 27.5” wheels. Most fat bikes still use the old 26” wheel standard. That’s because wheel size is measured by rim diameter, and the huge tires add several inches. The actual working diameter of a fat bike wheel with the tire installed is quite a bit larger than 26”. Some fat bikes use the 27.5” or even 29” standards, but 26” is most common.
  • A bit of weight – Rubber is heavy, and wheels are a major contributor to the weight of any bicycle. Fat bikes carry a lot of rubber, and will usually be heavier that conventional mountain bikes at equivalent price points. Low-priced fatties with steel frames can weigh over 40 pounds. Carbon frames, tubeless tires, and high-end components can drop the weight considerably, but you’ll pay a price for those features.
  • A bit of width – Wide tires force some structural changes on a bike, and one of those is that the distance between the pedal attachment points (known in technical circles as the Q factor) increases. Fat bikes designed for winter riding may spread the pedals farther apart to accommodate heavy clothes and boots. For most riders this isn’t a problem, but if you’re small or if you prefer to ride clipped into your pedals the greater width could be a comfort issue. The best way to find out is a test ride!
  • Soft tires – Fat bikes use much lower tire pressure than conventional mountain bikes. Many riders use pressures as low as 8 PSI for soft-surface riding, 12-15 PSI for trail riding, and a more conventional 20-25 PSI for road and urban riding. A small change can make a big difference in the way the bike feels, so you’ll need to experiment to find the best pressure for you and your riding conditions. Soft tires provide enormous grip and stability, but they can also require more effort to pedal.

All of those features contribute to the distinctive appearance and handling characteristics of the fat bike. Many riders love those characteristics, but they aren’t right for everyone, and you’ll have to decide whether a fat bike is right for you.

Why Ride Fat?

Fat bikes were originally developed for use on soft surfaces like snow and sand. Enterprising riders in Alaska and the southwest began experimenting with large-tired bikes in the 1980s, stitching rims together and using two tires side by side to produce custom bikes capable of riding on soft surfaces. These bikes remained at the fringe of the mountain biking world until 2005, when Minnesota-based Surly introduced the Pugsley, the first first commercially available fat bike.

Most riders don’t use their bikes in snow or sand, and if that was all fat bikes were good for they would have remained a niche product. That’s not what happened. Once fat bikes were readily available riders started trying them out on other surfaces and for other types of riding, and many people quickly fell in love with them. Enthusiasts praised their simplicity and stability, and beginning riders who saw staying upright as more important than going fast snapped them up. Enthusiasts raved about the sensation of “floating” over terrain and about the solid, secure feeling they got from riding on all that rubber.

That bike boom peaked in 2014 and 2015, with 37 new fat bike models introduced across those two years. Since then the market has stabilized: not all riders appreciate the aesthetics of the fat bike, and many preferred the agility, speed, and suspension of conventional mountain bikes. Fat bikes remain very popular, and they have staked out a solid market niche, but they don’t appeal to all riders.

So how can you tell if a fat bike is right for you? Consider these factors.

  • Fat bikes are great for beginners. If you’re new to mountain biking you’re probably more concerned with feeling secure on your bike than with high speed, agility, or slack geometry. The simplicity, sturdiness, and stability of fat bikes lets you keep your attention on the ride instead of the bike, which makes them a great choice for beginners.
  • Fat bikes are fun. A fat bike is a perfect choice for cyclists who ride just for the fun of it. Thare are fat bike-specific competitions and races on terrain chosen to favor fat bikes, but for most fat bike riders speed and endurance aren’t the primary goals. The same qualities that make fat bikes great for beginners make them ideal for riders more concerned with fun than with pushing their limits.
  • Fat bikes are versatile. Fat bikes are stable, comfortable, and serviceable on anything from urban roads to back-country trails to the sand, snow, and mud they were designed to dominate. You may want to adjust your tire pressure for different surfaces, but you can ride virtually anywhere on a fat bike, and you can ride all year.
  • Fat bikes are ideal for larger riders, especially if you’re on a budget. Many larger riders find that the entry-level suspension forks found on affordable mountain bikes flex under heavier loads, reducing both riding comfort and the lifespan of the fork. Rigid fat bikes are more durable and more secure, and the tires still suck up the impact of rough surfaces.
  • Fat bikes are affordable. Don’t get me wrong, if you want to spend a pile on a high end fat bike, you certainly can. The lack of suspension still allows bike makers to turn out usable fat bikes at quite reasonable price points. Don’t expect high-end components on these low-priced bikes, but you can get on a fat bike and on the trail without spending a fortune.

No bike is perfect for everyone, and there are also some potential drawbacks to fat bikes that you might want to consider before choosing one.

  • Fat bikes are slow. Of course you can ride fast on a fat bike, but with the same power input a bike with narrower tires will always be faster. If you’re not riding for speed that’s not an issue, but if you’re riding with a group that’s on conventional bikes you’ll have to do more work to keep up. If you’re riding with other fat bikers, that’s not a problem!
  • Fat bikes are heavy. The extra rubber means extra weight. That doesn’t just translate into slower riding: if you have to carry your bike up stairs or mount it on top of a car on a regular basis you might think twice before going fat, unless you can afford one of the relatively light high end models.
  • Fat bikes are less agile. The fat bike is great for rolling over terrain, but it takes a high degree of skill to navigate one through technically challenging terrain that involves dodging around rocks, roots, or other obstacles. If you ride technical terrain a conventional mountain bike might be a better bet.
  • Not everyone likes the look. The distinctive appearance of fat bikes can be divisive. For some riders it’s love at first sight. Others can’t stand them. If you really don’t like the style you have plenty of other options!

If a fat bike sounds the right ride for you, you’ll have plenty of options. Let’s look at what you expect to find at different price points.

Buying a Fat Bike

If you’ve decided to buy a fat bike you’ll have to evaluate your options. Your budget will be the single biggest factor governing your choice, but there are a few features you’ll want to consider.

  • Tire size. All fat bikes use oversized tires. Some models may only have enough clearance for tires up to 4”, others may accommodate tires up to 5” wide. This may not be a major issue for general riding, but if you plan to ride on snow, sand, or rough terrain you’ll want a bike with the widest possible tire clearance.
  • Frame material. Most fat bike frames are made from steel, aluminum, or carbon fiber. Steel is cheap but heavy, though higher end steel frames can achieve lower weights. Aluminum is durable, relatively light, and popular. Carbon fiber is lightest but most expensive.
  • Suspension. Most fat bikes use rigid forks, but some higher-end models use suspension forks specifically designed for fat bikes, like the RockShox Bluto or ther Manitou Mastodon. If you plan to ride steep or rough terrain, a suspension fork will give you a significant advantage.
  • Components. The most critical components to look at are brakes and drivetrains. Lower-priced bikes will use mechanical disc brakes. These work well but if you’ll be riding steep terrain or long descents the more expensive hydraulic disc brakes will be more comfortable. Drivetrain components are usually from dominant manufacturers Shimano and SRAM, and quality is usually proportional to price. If your riding involves lots of climbing a large gear range is an advantage. Other than that, cheaper components are heavier and less durable, but they will get the job done and you can upgrade as you go along.
  • Fit. Even the best bike won’t serve you well if it doesn’t fit. If you fall conveniently into a standard size category you’ll have no problems, but, if you’re tall, short, or in between categories you’ll want to put some care into your choice of size and model. A test ride and a consultation with the professionals at a good bike shop can help you choose a bike that fits you perfectly.

All of these factors are reflected in the price of your bike. More money will get you higher end parts and more quality, but you can still get a serviceable fat bike at a reasonable price. Let’s look at what you can expect at some different price points.

  • Under $500. You won’t get a high end bike, but if you want a mountain bike and you have less than $500 to spend, a fat bike is a great option. You’ll probably find a bike with a steel frame and basic components; it’ll be heavy but it will work and it will stand up to serious abuse. Mongoose has a reputation for turning out sturdy fat bikes at very accessible price points, and is a great place to start your search for a low-cost fat bike.
  • $500-$1000. Add some bucks to that $500 and you’ll start getting into lighter aluminum-framed bikes with better components, suitable for more aggressive riding. The Framed Minnesota 2.0 sits squarely in the middle of this range at $700, and features a SRAM drivetrain and Avid BB5 mechanical disc brakes. Closer to the $1000 mark you’ll find the KHS 4 Season 500 ($900), which adds hydraulic disc brakes to the mix, and the highly regarded Rocky Mountain Blizzard 10 ($1000).
  • $1000-$2000. At this point you can expect to find entry-level models from premium manufacturers. Frames will be aluminum and brakes will be hydraulic discs, and you can expect to move up to mid-range SRAM and Shimano drivetrains. You can certainly spend more if you want to, but a bike at this price level will satisfy all but the most demanding riders, and unless you have very specific needs there’s really no need to look for more. Standouts at the lower end of this price range include the KHS 4 Season 1000 ($1200) and the Norco Bigfoot 2 ($1100). At the middle of the bracket you’ll want to look at the Specialized Fatboy SE ($1400) and the Kona Wo, a value standout at around $1500. Push the budget up to $2000 and you’re looking at bikes like the Salsa Mukluk SX Eagle and the Surly Ice Cream Truck, bikes you can ride with confidence anywhere.
  • $2000 up. Push the price high enough and you can add as many frills as you like. If you want your fat bike with a carbon fiber frame, a suspension fork, and premium components you’ll have lots of options. It’s not really necessary for most riders, but if you want the best and don’t mind spending, bikes like the carbon-framed Salsa Beargrease ($3049), the well-reviewed Pivot Les Fat, which can accept 27.5 or 29” wheels (over $4000), and the suspension-equipped Canyon Dude CF 8.0 Trail ($3000). If you’re in this luxury bracket, be sure to shop around: there are many great bikes available and at that price you’ll want to get the right one for your needs.

If you’re reviewing fat bike specs (or any bike specs) it’s easy to get carried away with the hype that surrounds high-end componentry. That can be a mistake, especially if you’re on a budget. The expensive parts are beautifully made and provide spectacular performance at a very low weight, but they can also be very expensive, and you can have a perfectly serviceable bike without spending the extra money. Don’t worry that your mid-range bike won’t be up to the job: even relatively cheap bikes will usually provide very solid service, and upgrading your legs, lungs, and skills will do more for your riding than upgrading most components!

The Bottom Line

Fat bikes are popular for good reasons. They are sturdy, stable, and versatile, and they provide excellent service for beginning riders and many specialized riders alike. If you think you might want a fat bike but you aren’t sure, don’t let the odd appearance deter you! A test ride on a fat bike will tell you a lot, and if you’re like many riders it could be a revelation. It may seem like a new and unusual thing, but you may just find that it’s the right bike for you!