The world's most in-depth and scientific reviews of outdoor gear

The Best Fat Bikes of 2018

The Farley is our top pick for its fast-rolling attitude.
By Ian Butler
Thursday April 26, 2018
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Fat bikes have exploded in popularity in recent years. Who doesn't love the idea of being able to ride through winter's snowy and sloppy months? We rode some of the most compelling fat bikes on the market to determine key ride characteristics. These utilitarian bikes can serve as bikepacking rigs, snow bikes, foul weather commuters, or even daily trail bikes. Not sure you need all of that rubber? Check out our simple and effective hardtail mountain bike review.


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Best Overall and Best Buy


Trek Farley 5 2018


Editors' Choice Award

$1,729 List
List Price
See It

Stock Tire Size: 27.5x4.5
Fast-rolling
Carries speed + monster truck attitude
Prefers life on the ground
Poor brake specification

The Trek Farley is a fast-rolling monster truck. The 27.5x4.5 inch tires are larger than the standard 26x4-inch or 26x5-inch. This bike is at its best charging trails with a head of steam. The larger diameter tires help keep this bike out of bomb holes and are not easily disturbed by roots and rocks. Climbing is solid once you get the big wheels rolling. Not to be overlooked, this bike also takes home our Best Buy award. The $1729 price tag is impressive given the very high levels of performance. The build kit on the Farley 5 was impressive on the whole. Our biggest complaint about this bike is the SRAM Level brakes which simply aren't powerful enough for this big, fast, bike.

Read review: Trek Farley 5 2018

Best for Bikepacking


Surly Ice Cream Truck 2018


Top Pick Award

$1,999 List
List Price
See It

Stock Tire Size: 26x4.8
Aggressive Geometry
Steel frame with braze-ons for racks
Heavy
Low-speed handling is only okay

The Surly Ice Cream Truck is a steel bike that has a utilitarian feel. The Ice Cream Truck is capable of long bikepacking trips thanks to its braze-ons for racks and comfortable steel frame. Want to charge? The aggressive geometry on the Surly allows for excellent stability at speed. Despite its heft, the Ice Cream Truck scoots uphill effectively.

Read review: Surly Ice Cream Truck 2018.

Fat bikes allow for plenty of grip on greasy rocks and leaves.
Fat bikes allow for plenty of grip on greasy rocks and leaves.


Choosing Tire Size


Tire options have significantly expanded in recent years. There are designs ranging from fast rolling, XC-style tires all the way to aggressive freeride choices. All of the different widths, sizes and casings can get confusing. Tires can completely make or break a ride… and your bank account.


Width is an important consideration. This typically correlates to what type of surfaces you will ride the most. A 4.5-inch to 5-inch tire is going to be best in packed powder and fresher snow situations giving better chance of staying on top of the snow and not having to trudge as much. CYou would choose a narrower tire like a 3.6-inch to a 4-inch if you tend to ride harder conditions. This could be hard packed snow, ice, or dirt. The narrower tire is going to reduce rolling mass and cause the bike to corner and accelerate faster.

Rim width can drastically affect tire performance and compatibility. Too wide a tire on a 60mm or similar rim will lead to over-rounded tread profile and poor performance. Similarly a 100mm wide a rim with a narrower tire will also lead to a bad result. It seems like the industry has landed on around 80mm rim as a common size. 80mm rims are versatile as to what tire widths will play nice and the weight is often reasonable.

The Ice Cream Truck in its element.
The Ice Cream Truck in its element.

27.5x4-inch tires are becoming more common. The bigger diameter tends to hold speed well and roll over obstacles with greater ease compared to 26-inch tires. The downsides are that they don't accelerate or corner as quickly. Also, only a few manufacturers make this tire size.

Tread type is a very important consideration. Taller and more widely spaced lugs will help dig into looser snow, while still shedding the snow if it gets sticky. On harder surfaces the lower profile and more tightly spaced lugs roll much faster. Deeper, more aggressive tread on hard pack can creat a lot of drag.

Ice  snow  sand  mud  fat bikes offer excellent traction.
Ice, snow, sand, mud, fat bikes offer excellent traction.

Do I Need Studs?


The best way to determine if you need studs is by assessing your trail conditions and temperature fluctuation. If the temperatures fluctuate greatly your snowy trails are bound to get icy. If your trails get icy, studs are enormously beneficial. If you live in a super cold climate where the trails are packed powder or fluffy, you may not need studs. If you do choose to go with studded tires, brace yourself. Studded tires can approach up to $300 per tire. The upside is they will last you a very long time.

The other important thing with studs is to follow the manufacturer's recommended break-in procedure to set the studs. This is most often between 10 and 20 miles of pavement riding at you preferred riding pressure to ensure that the studs get embedded firmly and don't fall out.

Casings are another important factor for consideration. The tires that come on many entry-level bikes are the less expensive 30 to 60ish TPI or "threads per inch" inside the rubber of the casing. This is part of how these big tires hold their shape. The fewer TPI the heavier and less pliable the casing is. A tire with a 120tpi will be lighter and more supple. That is important because the more pliable a tire, the better it will morph over trail surface. This is especially important when running your tires tubeless. Going tubeless is less about weight reduction and more about freeing the tire from the oppressive friction that a fat tube gives against the inside of the tire. Tubeless tires also allow for even lower pressures.

Tire pressure is critical for optimal traction.
Tire pressure is critical for optimal traction.

Frame Material


Frame material is important for any type of bike. Stiffness and weight are the most notable factors for fat bikes. Ride compliance is a bit harder to decipher with the big volume tires and a bit less important than it would be on a 29" hardtail. Aluminum is still the best stiffness to weight to price ratio. As a result, most low-mid price tires are aluminum. Steel is not as common as it tends to add weight and lacks a bit of the snappy feeling of carbon or aluminum. Steel frames should also be treated to prevent rusting. Carbon has the ultimate stiffness to weight ratio…and a higher price tag. Making a fat bike light and laterally stiff is a game changer.

Hype about Q-Factor? Is it important?


Q-factor is the distance between the crank arms measured parallel to the bottom bracket. There has been a lot of discussion about Q-factor on fat bikes because the whole frame is wider. You need your cranks to clear the chainstays, therefore, you have to have a wider Q-factor. For many riders, this is a non-issue. For folks who might get knee or hip pain, it may be beneficial to look for a bike with a narrower Q-factor. This becomes increasingly important for longer and harder rides.

Do I need suspension on my fat bike?


But aren't those big tires your suspension? Well yes… and no. The wide tires at low pressures take some of the edge off and smooth out smaller bumps very well. Once the bumps are bigger and more frequent, the hits can be harsh and the bike can tend to get bounced offline. If the terrain you ride is rough and technical, then you might want to consider a fat suspension fork. If you are riding on mostly packed, groomed, or smooth trails you probably don't need a suspension fork or the weight it may add. Another thing to consider for cold temperature riding is that not all suspension or dropper posts are designed to work well below freezing. Full suspension fat bikes are few, but make sense for riding on rougher trails without snow.

Fat bikes provide four-season versatility.
Fat bikes provide four-season versatility.

Using a Fat Bike as a Daily Trail Bike


Plenty of folks use a fat bike as their daily driver trail bike. That said, it is not for everyone. It can be a viable option depending on your riding style and the terrain you ride. On loose or sandy terrain, they can offer unrivaled traction. Any situation where a regular trail bike does not have the float or grip, a fat bike can be beneficial. A fat bike is nowhere near as playful or nimble as a regular mountain bike. Riders who get aggressive might not like the undampened bounce of a fat bike at high speeds. Fatties are best as special terrain, off-season, or backup bikes

Caring For a Fat Bike


Caring for a fat bikee is not too much different than for a regular mountain bike. This stands to reason, as most of the components are not necessarily fat specific. The biggest differences are the importance of tire pressure and rust/corrosion.

Tire pressure can make or break a ride. Too much and you don't get all the benefits that led you to a fat bike in the first place. Too little and you risk sidewall/casing breakdown and potential rim strikes. Investing in a good, low-pressure gauge or a fat bike specific pump will help you find the sweet spot every time. Keep in mind that a fat tire will lose pressure when it goes from warmer temps inside to cold. The best thing to do is get the bike into the cold for 15 min before your ride and checking pressure before heading out.

Preventing rust and corrosion can be a losing battle. This is especially horrible in areas that use salt treatments on the roads. Your bike can be exposed to salt when on your bike rack or riding sections of road. It is not fun washing your bike in freezing temps, but it will help keep it in better shape. After a ride, let the bike drip dry and then clean with a light cleaner or bike wash. Make sure the chain doesn't go dry or get too built up with grime.

A fat bike will get you out and about during the snowy monthes.
A fat bike will get you out and about during the snowy monthes.

Gearing


Gearing on a fat bike is pretty similar to that of a regular 29" bike with one exception. In snow, you may want to have a lower range in case you encounter softer trail conditions especially while climbing.

Clothing


A key rule for fat bike clothing is to dress lighter to avoid overheating. You should start your ride feeling a bit cold. The heat that fat bike riding generates is much like xc skiing or alpine ski touring. That is why a layering system is important. If there isn't too much wind or precipitation, soft shell jackets and pants tend to breath the best making sure that you don't end up saturated with sweat. Wool socks and thermals are the best as they can still give some insulation when wet and they wick well. Making sure that you can still run a chamois under your bottoms is critical.

Using a thin, wind resistant cap under your helmet in warmer conditions is a good idea. On colder days, take a balaclava. Gloves for cool, cold, and super cold conditions are an absolute must. Footwear is critical. If you ride clipped in, there aren't a ton of choices. As with ski boots it is best not to skimp on quality footwear. Going with a boot or shoe designed for fringe seasons as a winter boot is not advisable. For flat pedals, choose a breathable, waterproof boot with a relatively low profile tread for pedal grip. A good long pinned pedal with a minimalist body that will clear snow easily is best.

It's a good idea to bring extra layers and/or a hard shell on longer rides. Having and extra set of gloves and socks can make thing go from bad to better in very short order. A pack of hand or toe warmers can get you out of a bind if your extremities get too cold.


Ian Butler