12 Things to Consider When Buying a Fat Bike
Special Contributor: Christina Grande of Alaska Bike Adventures
Buying a fattie? Congrats on your gateway to winter fun!
The best thing that you can do is take some test drives.
Borrow bikes from friends. Try different brands from different shops. My local bike shop rents demos by the week (at a discount) over the holidays. This helped me decide between the Rocky Mountain Blizzard and the Salsa Mukluk a few years ago.
In addition to how a bike feels, the type of riding you plan to do is your biggest consideration. If you are a beach rider in Florida then a fully-rigid (no suspension) fat bike is a great option. If your fattie will be your year-round rig for every type of terrain you may want suspension.
1. Standover height. This is the height between your crotch and your top tube. It is the most important part of your fat bike fit. When you put your foot down in soft snow you need clearance. If you are in between sizes, size down. This is something that your local bike shop (LBS) can help you with (but it doesn’t require a ‘custom’ bike fitting.)
2. Dropper post. A dropper post is a seat post that can be raised or lowered while riding with the push of a button on your handlebars.
Fatbike Girl: This is really a matter of personal preference. For winter riding on narrow and/or ungroomed trails, it’s hard to get your leg over your bike when you sink your foot in soft snow and lowering your seat helps. And dropping your seat makes it easier to start pedaling after you’ve put a foot down. Once you’ve started pedaling and gain traction you raise the seat back up to its regular height.
My partner thinks a dropper post is silly, but he is much taller than I am! I’m not currently running a dropper post because we now have more groomed trails in our area so I feel like it’s not necessary. In the old days the only grooming we had was when we all went out and stomped down the trails with our snow shoes!
Christina: Not all droppers are created equal in cold temperatures. Some work better than others. The PNW dropper post has been a really popular one for winter. I have been riding a Fox dropper for the past two years and now I am realizing it’s returning slower in cold temps from the first time I got it.
For dirt season, a dropper is helpful when going down steep hills. Lowering the seat for a descent allows you to ride more in control, faster and shift your center of gravity much more easily (without the saddle and post getting in the way).
3. Wheel size. 27.5” is the latest trend in fat bikes. Fans of the 27.5” wheel size claim that there is slightly more contact with the riding surface which provides additional stability and traction compared to 26″ wheels. However, this also makes the height of the bike a tad higher so consider standover height when weighing your options. And with a larger wheel size you gain some climbing ability but lose a little maneuverability.
Christina: If you are just starting to ride fat bikes and if you have an option for wheel size I would go with 27.5”. It will be great, especially if you have never ridden a 26” wheel size. I had a hard time getting used to the 27.5” wheel size after riding a 26” wheel size for many years. I thought the handling was not agile and snappy but I definitely noticed the faster rolling. After a few rides I started to get used to the wheel size and now I can’t remember how the 26” rolled. I personally ride 27.5 x 5 in front and 27.5 x 4 in back.
Also check out the 26” vs. 27.5” comparison on Fat-Bikes.com.
4. Wheel swapping. If you want to roll your fattie in the dirt months consider a bike that is configured to take an additional wheel set.
Fatbike Girl: I have a 29+ wheel set that I put on my Mukluk for bikepacking in the summer and for gravel grinding during the mud season.
A fat bike makes a great bikepacking bike.
In fact, my fattie is what propelled me into bikepacking in 2020. I even went solo on Mother’s Day! The Salsa Mukluk feels incredibly stable when weighted down and I’ve ridden technical single track fully loaded with no problem at all. In fact, it hugs the ground like it’s meant to be a pack mule!
(Bikepacking is camping with your bike, but your camping gear is loaded on your bike and not a backpack!)
Christina: For an additional wheelset, you could also consider a 27.5+ or just a regular 29er set up. I run 29 x 2.6 on my Otso in the summer. Super great for trails and still wide enough for chunky rides.
5. Tire width. You will want the widest tire possible if you will be riding trails that are not always groomed, will enter ultra endurance events, or if you plan to do some winter bike packing. A tire width of 4.8-5.0″ will provide the most floatation in soft snow. (A 4.8″ wide tire is plenty fat!)
According to Carla, Fatbike Girl contributor and “Princess Fatbike Faller-Offer”, in Nordic countries many people use a 4” tire width for commuting in the snow.
Fatbike Girl: I ride with a Surly Bud and Lou tire combination. They are 26” x 4.8” tires mounted on 80mm rims on my Salsa Mukluk. I also have the Bud and Lou on 100mm rims on my Surly Moonlander. In my opinion there’s nothing you can’t do on these tires.
Christina: Also, tire pressure can make a big difference while riding. You will adjust tire pressure on a fat bike more than any bike. 5 psi (pounds per square inch) will feel like a world of different between 10 psi. A low pressure gauge is good to have at first to get familiar what tire pressure feels like. (After a while you’ll be able to estimate pressure with the ‘squeeze’ test.) One of my favorites is the Meiser gauge. Or a digital gauge is great too!
Note that your tire pressure will be different on snow vs. dirt. You will also adjust your tire pressure according to different snow conditions. In soft conditions you will ride with a lower psi (around 4) for more floatation compared to hard-pack. You can also run very low tire pressures more readily with tubeless tires. See Determining Tire Pressure for Fat Bikes and The Rules of Fat for details on tire pressure.
6. Suspension. This is a personal preference and depends on your riding style and whether or not your fattie will be your year-round bike. If you are trying to save money then you can buy a fully rigid fat bike for starters and add a suspension fork later.
Fatbike Girl: I ride a fully rigid carbon Salsa Mukluk year-round, including technical single track. In place of suspension I simply keep the tire pressure dialed in so that I float over the rocks and roots. Essentially the tires are my suspension but I don’t bomb straight down super technical terrain like I used to!
When I upgraded from my aluminum Mukluk to a carbon Mukluk, the carbon fork made it feel like I had front suspension. Having a carbon fork soaks up a lot of chatter.
However, if you plan to ride your fattie year-round you might consider a front suspension fork. My local bike shop, The Bike Mill, recommends the Manitou Mastadon fork. It comes in both the 27.5 and 26 wheel sizes and two sizes for tire width. Also check out the Lauf Carbonara fork, which is built on the principle of “zero” maintenance and purportedly works in all weather conditions (think subzero) and stands up to salt and sand.
In my opinion full suspension on a fat bike is overkill, but I tend to be “old school.”
Christina: A front suspension fork is way fun. It makes the front wheel feel super planted. However, it does add weight to your bike. I ride ride a lot of “backcountry rides” where I am out in the middle of nowhere so I tend to play it conservative and swap all my fun stuff like a suspension fork to a rigid fork and lose the dropper post in case something breaks out there.
7. Tubeless ready or tubeless compatible rims and tires. Tubeless tires enable you to run lower pressure for better floatation in soft snow. A tubeless setup will also minimize the number of puncture flats and eliminate pinch flats. You will also shave off a little weight.
REI has a great post about the pros and cons of tubeless tires.
Fatbike Girl: I run tubeless which is sometimes a hassle in the winter when my valves get gummed up with tire sealant and I can’t readily adjust air pressure on the trail. There are ways to prevent and deal with this but it’s something to consider. I was trying to get my valve core unstuck one time and accidentally let all the air out of my tire. Also, if you change tires frequently you might want to run tubes. I’ve had some real issues with trying to get a tubeless tire unseated!
For new fat bike riders I would recommend starting off with tubes so that you can easily adjust your tire pressure and learn how much psi to run in different conditions — without worrying if your valves will gum up. You can always switch to tubeless tires later.
Christina: I’ve also experienced this same scary situation on the trails in single digits. Not a time I want to experiment with my stuff, but that’s when I learn best. Ha! When I was actually pumping air into my tire, my Lezyne pump unscrewed my valve core, letting the air shoot out of the tire too fast. That experience always made me check the status of my valves before winter riding. I also replace the valves at the beginning of each season.
Cleaning the valve (of the tire sealant) with rubbing alcohol works well. Also, check your valve core periodically throughout winter to make sure it is tight – ensuring that the donut ring is tight against the rim.
See video by Stans on Valve Core Maintenance.
If you run tubeless make sure that the sealant is rated for cold temps such as Orange Subzero Sealant.
8. Braze-ons. These are the bolts that are attached to the frame of your bike for water bottle cages or other types of attachments. For instance, my Salsa Mukluk has 5 braze ons, three on the frame and two on the carbon fork. (Note that all not all carbon forks have braze-ons.)
Since I have a size small bike frame my frame bag doesn’t hold a lot of gear. The multiple braze-ons give me more carrying capacity. Also, I prefer to carry more weight on my bike frame than in a backpack, especially in the winter when I’m constantly adding and shedding layers.
Alternator drop out. Some bikes have an alternator plate to mount a rack instead of using the through axle.
9. Frame type. Aluminum, steel, carbon or Ti. If you are like me, the type of frame is a cost consideration.
Steel. The first fat bike I ever rode was loaned to me for a 24-hour snow event. It was a Surly Pugsly. Heavy but durable. But hey, fat bikes aren’t exactly the thoroughbred of the racing scene anyway! You can’t go wrong with any of the Surly fat bikes in my opinion. I also like the way steel bikes hug the dirt.
Aluminum. My first fat bike purchase was a used Salsa Mukluk, a great entry bike because of the cost.
Carbon. When I upgraded to a carbon bike it was a game changer due to the weight savings and because the carbon fork made me feel like I had front suspension. However, I do worry about frame integrity because it is also my bikepacking bike and I’ve dropped it a number of times in scree fields.
You could consider running a carbon fork on an aluminum bike to improve your ride without shelling $$ out for a carbon bike.
Another less expensive approach to making it a comfy ride without having to go all-out carbon is upgrading to carbon handlebars. It will reduce the vibration in your hands and also cut the cold transfer into your hands like aluminum does.
Titanium: Very expensive but the people that ride Ti love it because it feels stiff and light with good compliance. (I hesitated to add this because there aren’t many people who ride Ti fatties!)
10. Hydraulic or mechanical brakes. Most fat bikes come stock with hydraulic brakes, either SRAM, Shimano or Magura. For hydraulic brakes, when you press the brake lever it moves fluid through a system that flows to the pads which press on the brake rotor.
Mechanical brakes are a cable actuated brake system, meaning that there is no fluid (i.e. hydraulic fluid) and they are easier to fix in the field. Many of the folks who do long winter races like the Iditarod Trail Invitational will run mechanical brakes. However, hydraulic brakes are better than they were back in the day. If they do not feel like they are engaging like you want, check with your local bike shop and see if they need to be bled.
Christina: I have done a few 100-mile races with hydraulic brakes and they worked fine. When in doubt about your brakes, take it in the shop and see if they are working properly. Also, the fluid in SRAM and Shimano brakes are different. SRAM uses DOT fluid and Shimano uses mineral oil. It is said that the DOT fluid will do better in colder conditions because it has a better cold-rated temperature.
11. 1X Drivetrains. Is it better to go with 10 speed, 11 speed or 12 speed? All of them are good but the 12 speed gives you a great range to climb hills. This makes a huge difference when riding up hills and on snow.
If you end up with an 11 speed and want to get a lower gear, you can change out the front chain ring to a smaller tooth count. So if you had a 30-tooth (30-T) chainring, a 28-tooth (28-T) chainring will make it easier to climb (this is what I did on my first fat bike). It’s nice to have a lower range of gears, especially when your bike is fully loaded.
12. Pedals. Many fat bikes will come with no pedals or cheap plastic pedals for test rides. You have the option to ride a fat bike with flat pedals or with clipless pedals.
Many folks prefer riding with flat composite pedals with threaded pins for better winter boot and pedal traction. It’s nice to have composite pedals over metal because it also cuts the cold transfer to feet. When riding in variable snow conditions, especially on ungroomed trails, having flats pedals is the safest route.
If you are an experienced rider and/or will be riding easy groomed trails or packed roads you may prefer clipless pedals. This will give you the advantage of having a more efficient pedal stroke. There are specific winter clipless boots – the best are 45NRTH and Lake. (The boots have different temperature ratings, also see Fatbike Girl’s Winter Cycling Boot Review.)
Fatbike Girl: I’ve always ridden with flats because our snow conditions tend towards “squirrely” and I put a foot down frequently!
Note that you don’t need specific winter boots for riding. I use my winter pak boots and duct-tape hotties to my feet!
Before you spec out your new bike be sure to set aside $$ for bike bags, bar mitts and studded tires if you’ll be riding through the winter. Bar mitts/pogies are oversized “mittens” that slide over your handlebars and keep your hands warm in addition to gloves.
Most winter riders have at least one bike bag (a frame bag or a seat bag, for example) to carry extra clothing layers. For my favorite bike bags and bar mitts see 5 Perfect Presents for Your Favorite Fat Biker.
Depending on where you live, many people who ride fat bikes will also buy studded tires, which could be $300 to $400 a pair. If you have freeze/thaw conditions in your area, it’s better to have ultimate traction on icy patches. There are different tire widths and tread patterns for studded tires. There are also “studable” tires that you can stud on your own which allows you to pick where to place the studs and how many studs to add (i.e. stud placement for corner tractor). And don’t confuse stud with Studd!
Finally, don’t let all of this techno-babble get in the way! My first fattie was a used Mukluk that I bought on eBay and I had several fab seasons on it. I learned as I went along and slowly accumulated bike bags and a kit that works well for me.
Roll fat, roll strong my friends!
A huge thanks to guest contributor Christina Grande, owner of Alaska Bike Adventures and day job at The Bicycle Shop in Anchorage. She leads fat bike glacier rides, winter day single track rides and multi-day fat bike trips in the White Mountains National Recreation Area near Fairbanks.