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Technical FAQ: Tubeless troubles

Technical expert Lennard Zinn offers tips and tricks for mounting tubeless tires.

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Have a question for Lennard? Please email him at veloqna@comcast.net to be included in Technical FAQ.

Dear Lennard,
I hope this finds you well. I have been having a devil of a time lately with flats. That’s probably more a run of luck than anything else, but what has made it worse has been that I have got some arthritis in my fingers now and just don’t have the strength to get the edge of a tire back over the rim. I have been using Continental GP 4000 II with my Boyd Rims but can’t find the 4000s anymore and so have had to switch to 5000s. I think that took the challenge from hard to impossible.

I end up having to use tire levers to reseat the tire, pinch the tube and waste another tube. For yesterday’s ride, I was down 3 tubes and the cost of an Uber home.

I am tempted to switch them to tubeless- the Boyd rims are Tubeless compatible. I’m not sure how effective that will be tough because I am using 23mm tires. With the 22mm internal rim width that is all that the frame will accommodate. I think that means I’d have to use a fairly high pressure- and so sealant wouldn’t be as effective.

I also wonder if a different tire would be better?

I would be grateful for any thoughts you might offer.
— Don

Dear Don,
It is not safe to run a tubeless 23mm tire on a 22mm inner-diameter rim. Do not do it.

There is insufficient retention, especially if you’re running the tire at high pressure. It’s not a great idea to do it even with an inner tube.

When you’re putting a tire on, are you finishing at the valve stem? The section you’re trying to push on last with your thumbs should be at the valve stem. You probably start with a little air in the tube, which is a good idea to keep the tube from twisting and from getting under the tire bead. However, you want to deflate it completely when you’re pushing the last bits of the tire bead over the rim edge on either side of the valve. Before doing the final push with your thumbs, go to the section of the tire opposite the valve stem—at the rim seam, and push the beads inward to get them to drop into the rim valley. By finishing at the valve and pushing the opposite section of tire into the rim valley, you minimize the rim diameter you’re trying to stretch the tire around. The further benefit is that when it’s tough to keep the inner tube from sticking out under the last bit of tire bead you push onto the rim, once the tire is on, you can suck those wayward edges of the inner tube back inside the tire by pushing up on the valve stem.

If you’re not doing these things, there might be hope for your thumbs to still be able to get your tire on. There are more mounting tips below, as well.
― Lennard

Dear Lennard,
I’ve been using tubeless on my gravel bike for about two years, but I am now building up a new road bike with disc brakes, and I have a new set of Campagnolo Bora WTO 33 wheels that I’m trying to set up with tubeless tires. I’ve tried Vittorias, which were impossible to even get on, and I am trying Bontrager R3’s now. I’m ready to give up! I’ve been riding and changing out clincher tires of many brands on different wheels — aluminum and carbon — for more than 45 years. It takes me an hour just to wrestle one tire on, then I’m too exhausted to do the second. I’ve watched the videos, read the instructions, talked to shop mechanics, and I JUST CAN’T DO IT!

When I did get one R3 actually on the rim, and I tried setting it up with Orange Seal using a Bontrager air chamber pump aired to 150 psi, the sealant just blows out at some point. I tried this 6 times. I figure I’ll just run tubes, but then there is the near-impossible task of getting a tire on. Is there an informal chart or cheat sheet that tells you what brands of tires mount the easiest on which brand of wheels? Experimenting can get expensive fast. Can I punt on tubeless and just find a clincher that will fit? My old rim brake bike has some ENVE clinchers that I can easily get tires on and off of. Looking at all the quality carbon disc wheels out there, they are all now tubeless-ready.

As a long-time experienced cyclist and garage mechanic, I’ve never been so frustrated with the industry. I don’t have a choice on quality wheels for the road. Gravel setups seem to work at least, though still not easy. Thank you for letting me both vent and ask for advice.
— Brent

Using a tubeless-ready pump to inflate tires to 160psi may help seat some times on some rims. (Photo: Greg Kaplan)

Dear Brent,
First of all, I’ll repeat my section from above on ensuring that you finish tire installation at the valve stem. If you’ve watched videos and gotten tips from mechanics, you likely are already doing this, but it is such a critical thing that so many experienced riders do incorrectly, I’ll repeat it.

The section you’re trying to push on last with your thumbs should be at the valve stem. Start with a little air in the tube to keep the tube from twisting and from getting under the tire bead. However, deflate it completely when you’re pushing the last bits of the tire bead over the rim edge on either side of the valve. Before doing the final push with your thumbs, go to the section of the tire opposite the valve stem — at the rim seam, and push the beads inward to get them to drop into the rim valley.

By finishing at the valve and pushing the opposite section of tire into the rim valley, you minimize the rim diameter you’re trying to stretch the tire around. The further benefit is that when it’s tough to keep the inner tube from sticking out under the last bit of tire bead you push onto the rim, once the tire is on, you can suck those wayward edges of the inner tube back inside the tire by pushing up on the valve stem.

If you’re already doing this and have trouble getting the tire on still, then try putting it on the rim from the other side. Because they are rolled into a circle, aluminum rims tend to have a slight difference in diameter from one edge to the other, so you might be trying to get it on over the taller side. This is worth a try even with carbon rims.

The Bead Biter tire levers have clothespin-type clamps on the end opposite the lever. If you have two or three of them, you can advance them one at a time, leaving one clamped to hold the bead from slipping back while you pry at the opposite end of the unmounted section of the bead. They can eliminate the frustration of a tight tire bead slipping back on one end of the unmounted section whenever you pry on the opposite end. Holding the wheel in the Tubeless Tower makes it even easier.

For inflating, you might try removing the valve core before inflation so that the air goes in faster.
― Lennard


Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder (www.zinncycles.com) and purveyor of non-custom huge bikes (bikeclydesdale.com), a former U.S. national team rider, co-author of The Haywire Heart,” and author of many bicycle books including Zinn and the Art of Road Bike Maintenance,”DVD, as well as Zinn and the Art of Triathlon Bikesand Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.” He holds a bachelor’s in physics from Colorado College.

Follow @lennardzinn on Twitter.