Welcome to our Ask a Mechanic column where our expert mechanic Daniel Slusser answers your bike maintenance questions. If you have a question for Daniel, please post it on our Facebook Wall or e-mail Daniel directly at firstname.lastname@example.org. In today’s entry Daniel discusses how to inflate tubeless tires without the mess and hassle. There is also a special section on how to make a custom tool that is a favorite of bike mechanics everywhere.
Question: I have been riding tubeless mountain bikes tires for a long time and don’t plan on ever going back to tubes. But, I’ve always struggled to get the tires mounted and inflated without make a huge mess of wasted sealant. It usually takes a lot of messing around with getting the bead just right so that the tire will bead up and seal. I am using a compressor after failing with a floor pump, but it is still difficult. Do you have any tips to make it easier? From: Devon
Answer: Done properly, tubeless tires can sometimes be easier to install than tubed tires. For all of you reading this that are scoffing, making sounds akin to a leaking floor pump, and about to click away, just hear me out and I think you will agree after trying these techniques. They work for both Mountain and Road tubeless equally well but I will use mountain as my example because they are far more common.
Preparation is key and that includes choosing the right tires, rims, and tools. Always use a tubeless rated tire. ALWAYS. These tires have a bead that is engineered to be air tight and consists of a square shaped cross-section that creates a better interface with the rim and also incorporates special rubber lips made to seal against the rim’s bead hook. For rims, always use one that is tubeless compatible. This will ensure that the shape of both the rim bed and the bead hooks are designed to seal a tubeless tire bead. Next, make sure you have a good valve. I like the WTB tubeless valves and the Stan’s No Tubes valves because they are compatible with and seal against any rim and they have removable cores. Removable cores are critical to making inflation easy.
Lastly, there should be some consideration given to the inflation method you choose to use. You want to use a method that gets the most amount if air into the tire in the least amount of time, in order to quickly seat the bead. Compressors are ideal. My next choice is the Lezyne Dirt Floor Drive Pump that is designed to move a large amount of air with each pump stroke. Seating tubeless mountain bike tire beads with this pump is remarkably pain free. After the Dirt Floor Drive I would choose a CO2 inflator followed by a standard floor pump.
Now that the parts and tools are sorted it is time to install everything. Begin by mounting the valve into the rim and tightening down the lock ring tightly by hand (don’t use pliers, just get it as tight as you can with your fingers). Then remove the valve core with a set of pliers or a blue Park Tool SW-3 spoke wrench which is conveniently just the right size for the job. Make sure that there is no sealant plugging up the valve. If there is dried sealant inside, use a sharpened spoke to pick it out (see below why everyone who rides should have one of these homemade tools and instructions on how to make one).
The next step is to mount the tire to the rim. Install both beads, one at a time, without putting any sealant inside the tire, as we will take care of that later. Now hang the rim with tire installed on a repair stand or wall hook so that there is nothing touching the tire. We don’t want anything to deform the bead and prevent a seal. An alternative to using the hook is to lay the wheel on top of a bucket or trash can with the spokes resting on the rim of the bucket.
Before you begin inflating you should don eye and ear protection, just in case. Now just use your inflator in such a way that you fill the tire as fast as possible and the bead will pop onto the bead hook with minimal effort. Stop once you get to 30psi. If the tire isn’t seating, then you need to stop and pull the tire bead toward the bead hook all the way around the rim and try again. If it still leaks, then use your hand to press down on the tire radially to force the bead against the bed of the rim to create a seal. Do this anywhere along the rim where you hear a leak. Then remove the pump and don’t worry about all the air rushing out of the core-less valve and the bead unseating. Just let it happen, the hard part is done.
Now use a Stan’s No Tubes 2oz bottle or something similar to inject the sealant through the core-less valve. 4oz is best for mountain tires, but you can get by with 2oz. Replace the valve core and inflate the tire again to 30psi. This should go quickly and smoothly because of the prep work done earlier. If you loose any sealant during this part of the operation it will only be a few drops. After inflation, shake the wheel again to distribute the sealant, but you can hold onto the tire this time now that it is inflated and sealed.
You are done! No mess and no headache. You may need to reinflate the tire a few times over the next two days until the tire fully seals. May your Stan’s last long and your tires remain flat free my friend.
Special Pro Tool Making Section
The sharpened spoke tool is the most basic, easily made, and frequently used tools by any pro mechanic. I use mine to dig thorns, glass, and wire out of tire casings, to flare the ends of cable housing, to pick at and clean jammed or corroded parts, unplug fouled valves and tubing, or to pry up small items in hard to reach places.
They are easy and cheap to make. Most shops have a few junk spokes laying around that they will likely give you for free. Just cut the spoke to length and use a grinder or some sandpaper to sharpen the tip and you are good to go. You can get fancy with them too and make a tool for fishing out cables from the inside of frames. Your imagination is the limit!
Daniel Slusser is a professional bicycle mechanic with over ten years of experience. He holds a bachelor’s degree in business administration from HSU and a master’s degree in history from Cal Poly University. When he is not riding, wrenching, or writing he enjoys spending time with his wife and two children.