Tire Pressure for a fat bike can be quite the adventure when you’re first starting out. It seems like everywhere you look someone has a different opinion. A regular bike pump won’t even register pressure below 10 psi. So how do you even know where to begin? In the world of fat biking the answer can be complicated. The main thing to keep in mind is to throw out everything you know about regular mountain bike tires. Fat bike tires are a different beast completely.
The giant tubes inside the tires help to support the sidewalls. Fat bike tire tubes are very durable compared to regular size mountain bikes. They don’t seem to be effected by “snake bite” style punctures from low air pressure like a normal sized bike does. I recommend that you setup your tires tubeless. It’ll cut a little weight from your fat bike. You’ll notice the difference if you go from tubes to tubeless when airing up your tires too.
That being said, I it’s important to experiment with different tire pressures whenever possible. The more you know how they feel at varying amounts, the more easily you’ll be able to select the correct pressure for your rides in the future. Start squeezing the tires by hand after checking the air pressure to get a feel for the stiffness of the tire. I air up that way most of the time now.
Go to high and you’ll be bouncing off of everything. Go to low and you get auto steer. Plus, you’re bound to get a nasty rimshot on rocky trails. Not to mention the extreme rolling resistance you get when going too low.
I have gone over unpacked snow and loose sand with 1-3 psi. While you can ride over almost anything with super low tire pressure, but the rolling resistance is almost 100%. Meaning every pedal stroke only moves you a short distance before you come to a full stop. Not too fun, but great for exercise and training.
I recommend that you purchase an air pressure gage that is designed for low pressure. Here’s the reliable one I use and recommend as it’s small and packable. Our High Pressure Pump It’s very portable and gives readings for fat bikes and mountain bikes up to 200 psi. It’s designed to fit both Presta and Schrader valves.
Prepare yourself to be blown away by how low these tire pressure numbers are. Again, forget anything you know about bike tire pressure. This is not a joke… I rarely get above 10 psi. At that level my tires are pretty rock hard when I squeeze them by hand.
Average weight rider of 170 lb. – For a good starting place use the chart below. Try a little more air in the rear tire than the front. This will help cushion your riding. *Use a little more air for heavier riders:
Loose sand: 4-6 psi
Wet packed beach sand by the surf: 6-8 psi
Rocky trails: 6-10 psi
Pavement: 10-12+ psi (Most fat bike tires have a max psi of 20)
Fresh snow: 1-4 psi (Everyone has a tough time with fresh snow so don’t worry. Fat bikes really need packed snow)
Packed snow trail: 2-6 psi (Packed non-cross country ski trails that are shared with hikers)
Groomed snow trail: 1-4 psi (So you don’t sink in and damage the trail)
The above chart is a great starting off point and should get you confidently riding a variety of terrain in no time. Doing a “squeeze check” with your hands on the tires will help you learn to air up or down your tires without a gage. It’s more about feel than anything for fat biking tire pressure. I prefer to ride with a little more pressure in the back tire since that’s where my weight is. The front tire I like to be softer so it has some shock absorbing properties.
In general, your fat bike will let you know if you have the wrong tire pressure. If you go too low then the sidewalls of your tires won’t hold up and you will be out of control while riding around even the smallest turns. Plus, you will begin to experience “auto turn” where the fat bike can’t maintain a straight line.
Optimal tire pressure is a vital factor in making you go faster. You can also use tire pressure calculator provides recommended tire pressure for Zipp wheels.