Fatbikes are a lot of fun. If you get a lot of them together, they are a blast!. What’s not fun are flats on a fatbike. Flats are never fun, but add in big wheels and the possibility of working in cold temps during the winter, and you have the recipe for less than smiles.
Tubeless is nothing new now a days. Tubeless wheels (typically) have fewer flats from punctures, and ride smoother. It’s pretty easy to understand why I wanted to convert my fatbike to tubeless. The problem?. There isn’t a great fatbike tubeless solution. There are no systems, no dedicated tubeless wheels (a big dollar idea), no tubeless tires, etc.
I decided to try to set up my wheels tubeless, even though it’s not supposed to work.
The Popular Options:
It seems like there a few schools of thought on the early fatbike tubeless methods.
- Ghetto Tubeless – Using a normal tube after slicing it open length wise thus creating a make shift rim strip with a built-in valve stem,. add sealant, inflate, and trim the excess tube if desired.
- Traditional – Add tape, install valve, add sealant, inflate.
I choose to attempt a traditional approach as it has the least weight and is the least complex. Some people build up the center of the wheel cavity with non porous foam to help seat the tire, I choose to skip this step because after the tire seats, it serves no benefit.
I used Gorilla Tape (both wide and standard widths), Stans valve stems, Stans sealant, Surly Holly Rolling Darryls, Surly Knard 120 TPI for the rear, Surly Big Fat Larry 120 TPI for the front, Surly rim strips, Stans injector, air compressor, floor pump, and a five gallon bucket.
How I Did It:
I cleaned the wheel thoroughly including the sides of the rim (1). I added a Surly rim strip (2). I added one layer of the wide Gorilla tape down the center of the rim carefully covering the entire rim strip, and then afterwards using the standard width Gorilla tape to cover both the left and right sides individually, carefully placing the tape all the way to the edge of the rim. I also used a pick tool to poke a small hole for the valve stem. It is important to make the valve hole smaller than the diameter of the valve (3).
I then inflated the tire to 30 PSI to ensure the bead seats on both sides of the wheel. Once the beads seated I carefully deflated the tire and broke the seated tire free on only one side of the wheel. I then removed the tube and then installed the Stans valve stem.
I then wrapped the tube previously removed around the outside of the tire. This helps push the tire to the edge of the rim, helping seat the tire when you inflate it.
I then used an air compressor to inflate the tire. If you hear any air leaking out, press on that area with your hand.
Once the tire starts to inflate, I stopped inflating with the air compressor and used a floor pump to inflate the tire to 30 PSI to ensure the bead was seated thoroughly. Once the bead is seated I carefully deflated the tire and removed the valve stem core. Using the Stans injector, I injected six ounces of Stans sealant into the wheel through the valve stem. I then re-inflated the tire with an air compressor initially. After the tire takes some air and begins to fill, I switched to inflating it with a floor pump to ensure I filled it to 30 PSI.
I then did the “Stans” shake to seal any leaks. If you don’t know what that is, there is a video detailing what I am referencing here.
After shaking the sealant onto the sidewall all the way around the wheel, I sat the wheel down on a bucket for about three minutes to allow the sealant to work its magic on the sidewalls of the tire.
I repeated the shake and bucket work at least three times per side of the wheel, rotating which side of the wheel is pointed down each time. If you are still leaking sealant and or air out of the sidewall, repeat this step until the leaks seal completely.
I then deflated the tires to about 12 PSI (my desired riding PSI), and repeated the shake and bucket trick two more times to be sure everything was sealed all the way.
It worked!. The Big Fat Larry tire was a real pain to get seated. The Knard seated without any real effort. I believe this was because the Big Fat Larry is a 4.8″ tire and the Knard is a 3.8″ tire and on the 82mm rim the 3.8″ tire has less tire per mm in width to displace. I think an air compressor is a must for mounting a Big Fat Larry tire on a 82mm wheel. The conversion lost about a pound or so in weight. They still ride wheelies just fine :) I’ll provide updates as I spend more time riding on them, but so far, I couldn’t be happier!