Converting mountain bike tires from tube type to tubeless - motivation? Goat Heads


Staff member
Since we are now living in an area with great mountain biking trails and goat heads, I decided to convert my mountain bike tires to tubeless. Tubeless bicycle tires have thick liquid in them that will plug puncture holes. No more stopping to change a tube.

A special thanks to @Azjeff who not only inspired me to change to tubeless, by telling me the horrors of goat heads, and also talked me through the process and took a couple phone calls when I got stuck.

I already had tubeless valve stems that came with my Specialized Stump Jumper FSR and ordered rim tape and MUC OFF sealant.

How difficult is this conversion? It's not. If you can change a tube, then you can convert to tubeless. It's really that simple.

Front tire removed. I had to dry the tire and wheel, as there was a bit of water inside, but no rust. I cleaned the wheel and the tire thoroughly.

These valve stems came with the bike and after 2 moves and 6 years I was able to find them!

The wheels were pre-taped with non-adhesive style bands. Convenient! I didn't have to tape the wheels!

Valve stem installed

Tube removed and the tire back on wheel, then MUC OFF goes into the tire. My tire size, 27.5x3 calls for 100ml. The bottle has a sight window and is conveniently marked with a scale in 100ml increments. The bottle comes with a soft filler hose, which is a nice touch.

I bought a Presta to Schrader adapter so I could use my air compressor to seat the tire beads. I highly recommend these as it makes bead-seating much faster and easier.

The tire was back on the rim and I was ready to take the bike for a spin to get the MUC OFF distributed around the inside of the tire. Just one problem, air was leaking from around the valve stem. At first I thought the problem was the valve stems, because the rubber seal shape looked like it may not be large enough to seal the valve stem hole. I took the tire off to inspect the stem to see if it might be leaking at the seal to wheel interface. I couldn't see anything wrong, but it was leaking there, so off I went to a bike store to see of they had valve stems with cone shaped seals. I asked the guy at the shop what he thought could be the problem and he said factory wheels often have bands without adhesive and that air was likely leaking around the band into the wheel cavity, then out the valve stem hole.

I picked up a couple of new valve stems with cone shaped seals.

The wheel tape looked fine, but I lifted the edge up to see if there was any MOC OFF under the tape and sure enough, lots of MUC OFF. The factory tape wasn't sealing. Which is understandable that in 6 years it probably hardened a bit and was no longer capable of holding air.

I cleaned the inner wheel surface and put adhesive seal tape to cover the spoke holes.

In the previous picture you can see the air between the tape and the wheel. You have to really work the air out with your fingers or better yet with a soft rubber type tool.

No air between the tape and the wheel.

I did use the factory valve stems to see if they would seal and they do.

Both wheels are done the same way and now with no leaks around the spoke holes to the valve stem.

I no longer fear goat heads.
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You forgot a picture of what a goathead is. These grow on a ground hugging plant and are as sharp when they're still green and attached as they are when they die and fall off the plant. Absolutely will ruin your day to ride through a goathead patch. Terribly painful to step on one that drops off a shoe in the house.
They look like I would kill every plant around me with fire and replant it just so I made sure I didn't have any. Good lord, those look like absolute torture to step on. I'd imagine pets have a hard time with them as well if they're nearby.
I run Mr Tuffy tire liners in all my bikes. Rarely have any issues with any my bikes. I run Schwalbe Marathons on my commuter bike so it's double protected.
I found the rear tire flat when I was getting ready to ride tonight. Hopefully the ride distributed the MUC-OFF well enough so that the tire stops leaking.
@Azjeff have you ever tried tire liners?
I tried to install liners one time, got frustrated and gave up. Went from just tubes in Pa to Slime tubes when we moved here because cactus and goatheads to tubeless when I got a Devinci in 2016 that was tubeless ready. Gamechanger.
I found the rear tire flat when I was getting ready to ride tonight. Hopefully the ride distributed the MUC-OFF well enough so that the tire stops leaking.
That happens sometimes. You did everything right.
We discovered them while in New Mexico, they go through a lot of things like the soles of shoes, tires and anything else they come in contact with. They are devilish!!!!!
I have yet to see one, even though we spent the winter in AZ. I'll bet they are hell for dog's feet?
It's still leaking, any ideas?
Pump it up and squirt all over with soapy water and find where it's coming out. Did you put 3-4 oz in?

I have yet to see one, even though we spent the winter in AZ. I'll bet they are hell for dog's feet?
You definitely know when the dog steps on one. Our dogs just stop and put a foot up until someone comes and pulls it out. We don't have many around where we are now but they were all over in the previous town/trails.
So you blue taped one wheel and not the other?
This is not the wheel that came with the bike. I had a wheel built with a Power Tap hub, which came pre-taped with sticky tape. It was this tape that had the leak. I retaped it with blue tape.
I jinxed myself 😂 Good tires and liners won't repel 10+ thorns. Had to go off road due to construction on the bike trail. Must of went right over the plant. Saved the front tire but not the back.