How To Seat The Tire Around The Valve Stem

Here is a new feature on this blog called "Ask Mr. Tubeless".  Think of it like the Car Talk show.  The readers asks any question about tubeless road bike tires, and I will supply the answers including wise cracks. You could pose your question to me in an email or as a comment anywhere on this blog.

Here is the latest question from a reader named Brian:

To say that it [installing tubeless road bike tires] can be a bit of a struggle is a severe understatement. At one point I seriously questioned whether I had a 600c tire. The 30 minutes I spent wrestling a Hutchinson Fusion 3 on a rim was no fun. At one point I seriously questioned my manhood, and debated whether my lack of grip strength was a sign of some aging disease. I managed to get it on, which at the time seemed a miracle, and had sore (and stained) fingers for the weekend. Of course none of that mattered as no amount of soap suds, tire sealant, and frantic pumping would seat the tire. I could not get the bead to seat near the valve stem, it seemed the rubber seal on the end of the stem got in the way. I may try yet again, on a separate rim (alas, not a Mavic UST) but am already contemplating an eBay sale to recoup my losses. I would pay a shop to mount the tires, but as you suggested, all my local mechs look at me as if I am asking to have a live rattlesnake installed on my rim. If you like the Fusion 3, watch eBay this summer as a pair of Hutch Fusion 3 are going to go to the lowest bidder.

Don't Give Up Brian

Many people claim the best way to install a tubeless tire is to start with the valve. I disagree.  I always do the valve last, and here is why. As Brian discovered, narrow road bike rims don't have that much room for the bead of the tire to fit between the rim and the valve stem. If you don't immediately get the bead seated, it will be unbelievably difficult to get the bead over the rim on other side of the wheel.  If you do the valve last, then you have no immediate worries about seating the bead. Also, make sure you are using a valve stem designed for road tubeless, as MTB valve stems are too wide to use in most road bike rims!
 
As for technique, I will seat 3/4 of the bead by hand, and then hold one side with my hand while inserting a blue plastic Park Tools tire lever on the other side, just an inch or so past the part that is already seated. I rotate it, pulling the bead over the rim, slide it over a centimeter or two and rotate it down and up again.  I repeat, holding the other end of unseated bead, until the entire bead snaps into place. This is most difficult with new tires. After the tire has been inflated and deflated a few times, you can even do this with your bare fingers sometimes.

As Brian found, if you can't seat the bead around the valve, no amount of miracle sealant (even milk : ) will seal your tire. Once both of the tire beads are completely over the rim, the easy way to fix this is issue is to loosen the nut on the valve stem almost all the way.  Then, push the valve into the tire, opening up room between the rim and the valve for the bead to fall into. Next, push the valve back into place by pushing on it through the top of the tire. Finish seating the valve by firmly tightening the nut. Inflate the tire with the compressor first, using soapy water along the bead if necessary.  Only after you have heard all the satisfying popping noises will you know that the tire bead is firmly seating. Then deflate the tire, remove the valve core, and add sealant. Re-inflate and you are good to go!

Please update us Brian to let us know how you did.

If you have any more questions,please feel free to let me know!