Dave's road tubeless doubts

This post deserves a TL:DR summary, which is: If you aren't super comfortable with road tubeless and willing to spend some time and expense figuring out exactly which combo works for you, and also willing to petentially suffer a reduction in the lifespan of your wheels, stick to tubes. With a whole bunch of data now showing superior rolling resistance with clinchers and latex tubes, that may be the best way to go in any case. The ability to use latex tubes is another bonus of aluminum rims. 

For mountain bikes, tubeless is mandatory. For cross, it has its challenges (which we've done a heck of a lot to help eliminate) but the benefits can be so profound that the juice is for sure worth the squeeze. For road, though Mike and I personally use tubeless, we haven't been evangelical. It comes with downsides, which we'll talk about here. 

A potential "do as I say and not as I do" instance

We've been observing and talking about spoke tension drop in clinchers for a couple of years now. Since I've done THE WORST job at tagging posts, it's hard to find all the posts on the topic, but these two posts from last spring are good examples. There were a bunch of forum discussions in the spring of 2014, but I can't even recall which forum they were on. We even made a video to show the effect last spring. 

Wheel Fanatyk has what might be the second best wheel blog out there, and they did a series of posts in the fall about this whole topic, including the outward splaying of brake tracks which we'd discussed in above-linked post called "Pressure Drop Follow Up." What they did in particular, for which I have huge appreciation, is measure a bunch of tires to find how tightly they will fit. Their whole methodology and execution of this is excellent. What their measurements reveal is something that anyone who's installed more than one kind of tire will already have known - tire bead circumference varies by manufacturer and model. 

They've also measured overall circumference of a number of different rims, but they haven't shown the more relevant tire trough and bead seat diameters (which are simple secondary measurements from what they've done and shown). The overall circumference is of little value in its own right as, for example, a Zipp 404 shows a large outer diameter, but 404s are known to be relatively easy to fit tires onto (perhaps too easy?).

In order to resist the higher inflation pressures of road tires, road tubeless tires need a tight fitting carbon bead. The carbon bead more or less doesn't stretch, which is critical to having the tire not blow off the rim, and thus to keeping your teeth in your head. In that respect, it works quite well, but at what cost?

Non-tubeless road tires have either wire or Kevlar beads (if you're reading this, you probably have Kevlar beads). You probably notice that your tires get easier to install over time, which is because the beads stretch a bit over time. This stretch reduces the constricting pressure that the tire imparts on the wheel. 

Compressive tire loads cause a reduction in the circumference of the rim. Wheel Fanatyk estimates a possible 1mm reduction in the circumference, and my calculation gave me an estimate of .1mm in diameter reduction, so they estimate a bigger effect but we're not that far off in the absolute. I based mine off of "the spoke tension drop is x, the thread pitch of a nipple is y, the spoke tension drop is equal to z turns of the nipple, therefore the diameter reduction must be..." The important thing is that we're both seeing the same effect, in the same direction, with reasonably similar magnitudes. 

Compression is bad for the wheel for several reasons. It takes more initial spoke tension to maintain the minimum necessary functional spoke tension. Compression changes the dish of a wheel. Compression puts stress on the rim that almost certainly shortens a rim's useful life span. 

At the risk of speaking against my book somewhat here, I have two road bikes in current use (one disc, one rim brake, otherwise more or less identical) and those four tires are all tubeless. It works fine for me, but on a scale of 1 to 10 in tubeless experience, I'm about a 643. So if you are willing to invest time and money into getting your road tubeless set up perfectly, knowing that it comes with the potential to compromise your wheels, then it may be worth it to you. Otherwise, tubes are your best bet. 

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Greg – It's great that you're having a good experience but shouting down dissent and advocating that this is all roses and puppy dogs in all regards isn't appropriate or, frankly, welcome here. Thanks.


Pro Ones are the way to go . I have them on my carbon tubeless hoops as well as on my alloy rims .Completely problem free on both applications . I put them on and remove them from all rims without any tools . Faster ,Smoother , Lighter , Reliable, Easy to mount and remove .Throw away your tubes folks its 2017 .


Hans – Good question, which I probably can't answer as comprehensively as you or I wish I could.First, there appears to be a risk of me being generally seen as anti-tubeless here. I'm not. Just look at my bikes – I've probably ridden tubeless more than most, and helped more people try it on road and cx than like kinda almost anyone. My point is that it takes the bad things that clinchers do to wheels and magnifies them. I don't think either camp is wrong, but I quite do think it's wrong that there are camps in any case. People should use what works for them, not what anyone tells them to do or what's hot this week. Despite being accused of the contrary, my attitude is reflexively and resolutely one of free choice and free.expression.That said, there are no absolutes in this. A tight clincher tire (whether tubeless or not – and from here on "non-tubeless" will be called clincher and tubeless will be called tubeless) exerts compressive force on a rim. The tighter the tire, the more compressive force. If you put a tubeless tire on, and inflate it, and measure the tension drop, and then deflate it (in the spirit of the Patriots playing in the Super Bowl tomorrow) but leave the beads out on the bead shelf, the spoke tension drop will stay about the same. Air pressure doesn't introduce more compression, the carbon bead provides all of it. And that carbon bead won't ever really stretch – that's what makes it necessary to use in a tubeless tire. A tight clincher will do about the same thing through being inflated. Then deflate it, and the spoke tension returns almost back to the starting point if not all the way. The wire or Kevlar bead in a clincher stretches. Notice how installing a new Conti GP4000 takes some effort and will, but then isn't ever that tight again? Inflation is a variable in spoke tension drop there. And inflation doesn't seem to be as effective at compressing the rim as the tubeless tire's carbon bead is. My guess is that a lot of rims have less compressibility than air (which is a compressible gas, after all), but that carbon beads are the master of all. Those f'ers take charge. But again, not all carbon beads are the same tight on all rims – rims vary and tire beads vary, as shown in the Wheel Fanatyk thing I linked. So there are no absolutes. Also I ride 23mm tires all the time. Of course they're tires that are labeled 23 but measure somewhere in the 25 to 26mm range, which is just fine for me on road. Clearance gets thin when I use a rear tire that's actually 28 (as many "25"s are), and at 160 I just don't need that big a tire. New England roads suck, but I'm not doing Paris-Roubaix here, so it works great for me. JLP -I thought I addressed it pretty comprehensively in the post prior to Hans's, but it was two posts not one, the second one more adamantly stating the absolutist perspective of the first one, with the last line of the second being what I took to be an "I'm right and everyone else is wrong" statement. Also no info on what rims the excellent experience with Pro Ones has happened with, so no one gets to learn about that, and which reinforced the sheen of "this always works way better if you don't think so you're wrong." If you haven't guessed, I don't think absolutist statements hold a lot of value. As I looked at it from the perspective of someone deciding whether to post a constructive comment, it seemed to me that we were headed in the direction that any non-pro-tubeless and more specifically non-pro-Pro One comment would be met with a similar response. That pattern had been established. And that stifles free speech and meaningful discourse, which despite accusations to the contrary is the opposite of what I want to do. Of course it's easier to misconstrue tone in writing than in verbal speech, and once again I'm willing to be wrong, but that was my take. Thanks and have a nice weekend.


Dave, What did Greg say that was so offensive? I read his comment and there was nothing there that should have warranted your response. You (Dave) need to calm down.


Wondering if you guys can quantify the difference in tension drop between tube and tubeless setups. I know tension drops when mounting a tire, but didn't know it was significantly greater for tubeless. I haven't observed that, but can't say I have measured for that specifically. I usually increase build tensions with this in mind . I have 20k miles on my commuter wheelset that I run tubeless (Pro One). I have not been on tubeless the entire life of these wheels, but certainly once I switched (~12k miles ago) I will never go back. Despite a handful of punctures, no flats on Schwalbe One and then Pro One tires. That is worth it (and they are really nice tires). I will say that the value is lost in me at < 25mm tires as pressure is too high (I surmise) to seal all but smallest punctures. But who wants to ride 23mm tires anymore.


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