This is a topic that I enjoy talking about, because there isn’t really a wrong answer.
Should I convert to a tubeless mountain bike tire system?
There are many fierce opinions on this topic. There are definitely pros and cons to both sides. Everyone is familiar with the foloowing scenario. You are riding along enjoying yourself on your bike when you hear the hiss and soon the whump whump whump as your tire goes flat. You look down and see several thorns stuck in your tire, and all your precious air is gone.
I can’t count how many flats I got as kid growing up, and how times I had to yank out the inner tube and glue a new patch on. This got old really fast. This is the main reason the tubeless system was developed: to reduce flat tires. Flats are caused not only from thorns, but also pinch flats, where the tube is pinched between the rim and the bottom of the tire.
So does this mean you’ll never get another flat? No. But! The likelihood and frequency of flats will be very much reduced.
Tubeless Mountain Bike Tires.
The differences between tubed and tubeless systems are several. The obvious is the removal of the inner tube. There exist two tubeless systems in the biking world: the UST standard (which stands for Universal Systeme Tubeless) and the conversion method. The UST standard uses a sealed rim that mounts to a UST bead tire. This can get pricey as a new rims are required, along with the labor needed to build a new wheelset. The UST system is normally run without sealant.
The other option is the conversion method, or “ghetto tubeless” as many cyclists have nicknamed it. This method was pioneered by Stan’s No Flats group. The conversion system can be used with your existing rims and tires if desired, while others opt for tubeless specific tires.
This involves dismounting your existing tires, installing a sealing rim strip around the circumference of the rim where the tire bead will sit. Then the tire is mounted on one side, several ounces of special sealant added inside the tire, and the second bead of the tire mounted. At this point the tire can be inflated. Sometimes compressed air is needed to get the beads to seat so the system will seal. This last step can be tricky depending on the particular tire being used.
Some tires will seat the bead much easier than others. Once the tire is inflated and beads seated, the wheel assembly is swished around, and laid on one side for ten minutes, then the other to allow the sealant to seal against the bead surface. It can take several hours and up to a day for all the little gaps and leaks to seal up. Once they’re sealed though, you’re good to go.
The sealant is usually latex based, although several other types are in use. How it works, is when a puncture or leak occurs, the small latex particles contained in the sealant will be pushed by the leaking air into the hole where they clump together and seal the hole. Pretty nifty. This is very nice in areas with lots of thorns, such as the southwest US.
Pros and Cons
Pros: I’ll stick to the ghetto tubeless here, as that’s what I’ve run. Fewer flats! I’ve had many thorns stuck in my tires, and I just pull them out, rotate the tire, and presto! The puncture is sealed. I’ve even punched a branch 1/4″ in diameter through my tire and the hole sealed up (shown below). Neat stuff!
Also, a significant benefit to tubeless is being able to run lower air pressures in your tires. Lower pressures will give you a smoother ride, increased traction by making the tire softer so it can deform to the contours of the ground. This has been a noticeable improvement to me, personally.
Cons: As great as a tubeless set-up is, there are downsides.
First, in the ghetto tubeless set-up, the sealant can dry out after a few months so you need to replenish it periodically, even more often in a hot climate.
Second, you should still carry a spare inner tube. A large sidewall cut or large puncture may not seal up with sealant, so a spare tube would be needed. I recently needed to use a spare tube to get me home off the trail during a ride. My sealant had dried out and I didn’t add any more.
Here comes the third con: it’s messy. Installing a tube on the trail to get you home after a flat can be messy. All that sealant in that tire needs to come out before you can install the spare inner tube. It can get messy.
Fourth, some tires fit and seal better than others. Depending on the tire you use, your mileage may vary. Fifth, not much, if any, weight savings. Depending on your choice of tire, and quantity of sealant, you might not be reducing the weight of your wheels. This may not be a factor to you, but it is something to keep in mind if you’re trying to shave weight from your bike.
Verdict: I love tubeless! Fewer flats, better traction, and smoother ride via lower air pressure make it totally worth it to me!
Feel free to comment if you have any questions and let me know of your experiences if you’ve run tubeless before.