How To Convert Your Fat Bike to Tubeless Using a Split Tube

I recently purchased a Motobecane Boris X9 fat bike. Of course, I immediately started to customize it! I was very unfamiliar with how, or if I could, go tubeless with my Vee Mission 26×4.0 tires on my Weinmann HL-80 rims. These “lower price point” rims and tires can be found on fat bikes that cost over twice as much as my Motobecane did, so this how-to will be useful for a wide range of fat bikes.

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To save weight initially, I took out those heavy stock tubes and put in some 27.5in. standard mountain bike tubes. They worked great at first, but after I blew my front tube on my first fat bike ride, I knew I needed something a little more durable.

After many hours of research, including reading, YouTube videos, and speaking with others who have tried tubeless setups, I concluded that the split tube method is the best setup for these types of rims. Best of all, it’s relatively inexpensive and easy! Here’s what I used for the setup:

  • Two 26×2.4-2.75″ Presta valve tubes
  • Bottle of Stan’s NoTubes sealant
  • Closed cell foam (I used a sill seal gasket I picked up at Menards)

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To begin, remove the tire and tube. Put on the new tube and inflate it a little. Then, cut the tube down the middle, all the way around. There’s a seam down the middle of the tube to guide you.

Note: I used 1 24″ tube instead of a 26 for a snug fit on the rim. I’ve even heard of some people using 20″ tubes.

After the tube is cut in half and folded over the rim, wash out the inside of the tube with some soapy water. Then, take the tube off the rim.

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Now, cut the foam to fill the concave area in the rim. I used two separate layers of foam, each held together with a small piece of duct tape. You might only need one layer depending on the brand or thickness you use. The foam should at least fill the concave void. Make sure you poke something through the foam to create a small hole where the valve stem hole is located.

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Now, slip the tube on over the foam. Tighten down the nut on the valve stem and center the tube on the rim.

Now it’s time to put on the tire. It should be a snug fit. You might need tire levers to get it on. Make sure the foam and tube stay as centered as possible when installing the tire. Don’t worry about the tire being completely seated at the edge of the rim: it will pop into place once you inflate the tire.

Next, inflate the tire. I used an air compressor, but it could have probably been inflated with a floor pump. The tire should seat nicely and hold air. Now, you can deflate the tire and add 3oz of Stan’s sealant by either removing the core on the valve and injecting it (easy way), or pop part of the tire off and dump it in (hard way). Since the tires on fat bikes are quite large, you may choose to use extra sealant.

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Finally, trim off the excess rubber. I left approximately a half inch all the way around. You’re going to want that little extra if you plan to remove and reinstall your tire on the same tube in the future.

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I did not ride my bike immediately after the tubeless setup. The next morning my rear tire was flat, but the front was still holding air. I aired the rear tire back up and rode it around on various terrain and could not get the tires to burp air. For a good test, I still need to give it a good, long, aggressive ride. I am impressed so far, though. The true test will be how it holds up in the brutal Wisconsin winter at low pressure!

This is not the only way to set your fat bike tires up tubeless, but it worked best for me. I hope it saves you time if you are looking to do the same thing.

Now, go ride your bike!

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