Tubeless 101: Part 3

If you are re-using a previously mounted tire, make sure the bead area is clean!

Tubeless 101: Part 3

If you missed Part 1 or Part 2, please go back and review those posts as these are meant to be a series.

Last time I went over how to dismount a tire, I gave some tips on sealant recovery, and in this post I will discuss preparations for mounting either a previously used tire or a new tire on a freshly prepped rim.

The first order of business is to make sure that everything necessary for good seals inside your system are clean, fresh, and in good shape. I recommend that anything that looks suspect be replaced regardless of its age. You may have had that tubeless tape for only a few months, but trust me, if it looks the least bit compromised, it is far easier to deal with it now, when you have everything apart, than when it fails you on that 50 mile ride out in the middle of nowhere. Never mind the frustration of having done all that work to mount a tire and then having to peel it back off because you didn't decide to replace the tape, or put in a new, fresh valve stem. Trying to 'get by' can get you in trouble. And in my experience, it isn't worth the risk.

Remember folks: Tubeless tires are not for everyone, nor do you need tubeless tires in many cases. And also: Tubeless tire set ups are not only more technical and maintenance intensive, but more expensive as well.

Still determined to go tubeless? Okay, moving on now.......

Cleaning up a previously used tubeless tire for remounting.

 Cleaning up the old tires is a must for good tubeless set up. So I would concentrate on the area of the bead of the tire. The part that is to seal onto the rim is a critical point and must be free of old, coagulated sealant, or you risk a failure or a lot tougher time re-seating the tire on the rim. How you accomplish this clean up is going to depend upon what sort of sealant you had in there.

Orange Seal makes a "skin", as does Muc-Off No Hassle Puncture Protection Sealant. My "home brew" does as well. In these cases, a peeling off of the old sealant seems to work fine, but it can be a tedious job. Generally speaking, you may as well just do the entire inner casing. Other sealants, like Stan's or Caffe Latex don't make a skin, but will leave a layer of sealant, or coagulate into "stanimals" which you can easily remove. To get all the remaining layers of sealant out. you can scrub with warm water and soap, or....... A certain energy drink that comes in a black can with a green "M" on it will take off the sealant. Just pour some in the tire casing, slosh it around, and dump out the remaining sludge, wipe down, and you should be good to go. Really. It works, and I've tried it, but you can do it the traditional way if you'd like.

The next bit you need to have perfectly clean is the rim well. That is if your tape is the least bit compromised. I use rubbing alcohol to clean off any skin oils or dirt. Then I start re-taping the rim starting opposite from the valve hole. I always, always do two rounds of tape. The risk of having the tape fail in a spoke hole drilling is just not worth trying to get away with one round of tape. By the way, many OE tape jobs are just one round, so if your bike came with pre-taped wheels, best to check that out.

I like to use tape that goes all the way to the rim bead wall. Covering where the bead of the tire sits will not only give you a better seal, but it will make the tire fit tighter too. Running tape slightly too narrow, or tape that you have to run on one side, then another because it is too narrow, is a bad idea and will cause a leakage leading to failure eventually. Conversely, using tape that is too wide is obviously a bad way to go as well. Any wrinkling should be kept to a bare minimum and taking care in laying down the tape will reap dividends down the line.

Muc-Off tape, Orange Seal valve, in a Shimano GRX rim.

One technique that does work well, but takes extra time, is to go ahead and mount a tire with a tube and air it up with the newly installed tubeless tape. The pressure of the tube and tire with air presses the tape into the rim well and gets a good seal on the rim. But not everyone has that kind of time.

Now the last bit which is important for the set up is probably one of the most overlooked bits. The valve stem and in particular, the valve core, are critical to get right or your tubeless set up will be problematic and prone to failure.

Valve stems come in a lot of variants. My favorites, as stated before, are made from chrome plated brass. These are sturdier and less likely to bend, or come unseated within the inner rim, which can cause leakage. In fact, I'm not a fan of having anything aluminum in the valve assembly. Generally speaking aluminum threading is weaker, the aluminum itself is prone to oxidation due to the sealant carriers in many sealants, and their bases many times are suspect, in my opinon, in comparison to brass valve stems. It is tempting to want to save weight and have pretty anodized flashes of color here, but I'm bot convinced this is such a great idea.

One more thing- Make sure you get the correct length valve stem. If you have a deeper profile rim, especially carbon rims which typically are aero and deeper, then you'll need a longer stem. If you have more typical aluminum rims which are not very deep in profile, then get shorter ones. Do not use a stem longer than you need because when you start using a pump it will act like a lever on the stem and a long stem may bend or break off, if it is aluminum. You can also compromise the inner seal at the base of the stem inside the rim by bending the stem too much in a pump head.

New valve core (top) and two bad ones.

Sometimes when remounting a tire I will replace the valve core. You can remove these and upon careful comparison with a new one you can easily determine if the rubber seal or plastic seal is compromised. Valve cores have direct contact with sealant and can corrode, the rubber and plastic can easily be deformed, broken down, and the brass bits can fail due to oxidation. In fact the middle core above has a frozen outer nut, so you can't even close the valve anymore. A cursory glance at these makes it seem that nothing is amiss, but I would not use the bottom two cores at all. Get a new one if you aren't sure. It's well worth it.

Standard Presta nut (center) and an aluminum nut (left) with a stepped nut on the right.

Presta valve nuts are even important. I like the stepped, brass/chrome plated ones because I can get a firmer grip on them for making the valve stem seal against the inner rim well. Regular nuts are hard to get a hold of. Aluminum ones are hard to get tight enough before they strip out sometimes, and that's why I don't like them.

Okay, got all that cleaned up, installed, and ready to go? Next time I'll cover the final details regarding mounting tires, introducing sealant, airing up and setting beads, and finally the tricks I use to seal up a new tubeless set up. NOTE: I sometimes actually have used, or am going to use, products and styles of doing things I don't necessarily agree with. The aluminum valve stem pictured above in the rim well is one of those things. I do this to prove to myself, and to test for review at times, products that are worthy or no, disregarding any preconceived notions I may have. So, eventually I get informed opinions, and not just guesses. Hopefully these posts are helpful. Stay tuned for the next one coming soon.