VicBC_Biker

Right; that makes sense.
A friend who is a tubeless fan got the LBS to switch the bike to tubeless. When I asked about roadside repair, the answer was "I'll put in the tube I carry if that's necessary".
"Have you practiced takng the tubeless tire off the rim and re-installing?"
"No, I'm not going to do that for fun since it will be so messy with the sealant and I'm not sure I can re-seat the bead with my floor pump."

Living on the edge.

The one time that friend had a tubeless big leak, he was near home/LBS and limped back with no drama, so that part worked OK.

Sorcerer

I prefer running bikes tubeless.

But this weekend I rode a mountain bike with inner tubes and I have to say it was more difficult and exciting. These were big rides.

I will convert to tubeless mostly for the increase in traction, compliance, and resistance to flats
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downtube42

I was 30 miles from the end of a 600k, when i ran over something that put a 1/2" cut in my GP5000, right down the center. Sealant spraying like mad. I rolled the bike until the cut was on the bottom, and sealant just poured out. Plugged it, CO2 , and was rolling just like that.
That was a few weeks ago. Today i finally replaced the tire. I've never needed anything but a floor pump to seat tubeless.

There was one heck of a thing growing inside the tire. Looks like swamp thing.

terrymorse 

Hmm. About those perceived "benefits" of tubeless:

Traction: How does tubeless improve traction over tube-in-tire? I'm skeptical of this claim. Traction = f(contact_patch, rubber_compound, tread_pattern). Are these parameters different in a tubeless? I doubt it.

Compliance: Another curious claim. Compliance = f(casing_stiffness, rubber_thickness), and the mass of a tubeless tire is about equal to a similar tube-in-tire, so the compliance ought to be roughly equal.

Resistance to flats: Other than the pinch flat advantage over some tubes (latex tubes are also resistant to pinch flats), the tubeless "resistance to flats" is provided by liquid sealant, which also functions well inside an inner tube.

Advantage tubeless? I'm still not seeing it.

VicBC_Biker

Aren't 'traction' and 'compliance' related to the tire pressure (and tire choice) more than the presence of a tube? If tubeless allow lower pressures, perhaps this is the thinking?
Really, looking at the tire pressure online calculators, there isn't a great deal of difference in recommended pressures between tubed and tubeless.
More than once I have heard stories like this:"I ran tubes and pumped the tires to the number on the sidewall. Then my LBS switched me to tubeless and told me to inflate to xx psi. Huge difference!! I'm convinced!!!"

Tubeless does eliminate pinch flats (replaced with 'burping' ??), and sealant and plugs can fix some holes, so perhaps that's the basis for the 'resistance to flats' statement?

Sorcerer

I don't see it either. Truth is, I feel it.

My opinion and experience come from tubed and tubeless mountain biking..

The closest thing I have to a road bike is a gravel bike with 33mm tubeless tires on it.

When I went through the process of transitioning to tubeless tires it was not easy. I was skeptical.

Champlaincycler

Have avoided this thread until now, just a lot of posts and a fair amount of reading. Just read all the way through. Lots of thoughtful reasons to stick with tubes or go tubeless, most having to do with convenience or hassle, or lack of same. Little discussion , more casual mention, about speed and tire pressure. Forgive me if I overlooked something.

There was a mention of a 2 mph gain from going tubeless, seems like a lot to me. Also, lots of talk about reduced tire pressures when going tubeless. Can someone explain to me why you can run lower pressure with tubeless tires and still gain speed. I'm in to lower pressures already and like wider road tires (32-38), appreciate that I can be faster and more comfortable on the roads I ride. How does tubeless make me faster? Apologize if this is too simple a question.

Eric F 

Lower pressure = larger contact patch = more traction
Lower pressure = more compliance
I know of very few people that run sealant inside inner tubes. If you're going to use sealant, why bother with using a tube?

terrymorse 

Lower pressure may be run in either a tubeless and tube-in-tire configuration. Since a tubeless tire has larger internal volume, the tubeless tire's contact patch at a given pressure will be smaller than an equivalent tube-in-tire's. Therefore, less traction at a given pressure.

The one point where tubeless has an advantage is at very low pressures, where a tube-in-tire runs the risk of a pinch flat (which can be mitigated by using a latex tube). But what's the use case for low pressure, high traction on a road bike? Unpaved roads?

At the same pressure, a tubeless tire is less compliant.

Probably because it's trivially easy and quick to replace a punctured tube, so few people bother to use sealant.

if you're going to use sealant, why bother with tubeless?

Eric F 

You're making comparisons at the same pressure. I'm not.

I used tubed tires for years. I understand how they work and how to repair them. My most recent bike purchase included tubeless tires.. It took me a bit to understand how the system works, and how to deal with them on the side of the road. It didn't take me very long to realize that I won't go back to a tubed tire. A comfy ride with no pinch flats? Nice. Almost zero concern about small punctures? Excellent.

Clearly, tubeless tires aren't for you, Terry. I respect your knowledge in a lot of areas, but your justifications on this argument don't make a lot of sense to me when I compare them to my real-world experiences. You do you, brother.

terrymorse 

I’m seriously looking for objective facts about the benefits of tubeless over tubed. Other than avoidance of pinch flats, I can find none that stand up to scrutiny. Most of the claimed benefits mentioned here are knocked down easily with just some simple physical reasoning.

But I’ll keep looking.

PeteHski

Main benefit for me is less flats and easier external plug repairs when you do. One minor benefit of the lower pressure is that it makes life easier when using a mini-pump to re-inflate.

If you don’t get many flats and you don’t mind having to remove the wheel and tyre to swap/patch tubes then tubeless is probably not for you. But those are hassles I prefer to avoid.

terrymorse 

Are those plug repairs permanent, or are they more of the "boot the hole, cross your fingers and hope you make it home" type that are common to tube-in-tire repairs?

PeteHski

IME they are permanent, although that is based on mtb tubeless experience. I’ve yet to need them on a tubeless road tyre as I haven’t had a flat in the 2 years I’ve been running them.

tomato coupe

Yes, they're permanent ... until they're not.

GhostRider62

I made that statement in a Freshman engineering physics class. The Nobel Prize winning Professor trashed me. I rebutted that my 1970 1/2 Z28 turns 12's if I run wider tire tires but i can't hook her up with narrower rubber. Science. He still brutalized me.

One reason to run sealant inside latex tubes is to significantly slow down the rate of pressure loss to minimize the risk of crashing. Depending upon the geometry of the bike and ability of the rider, those couple of seconds could save at least some skin. I ride a low profile recumbent. If you get a quick flat on the front tire, you are more than likely going down. My average speed on flat roads is about 30 mph. The first time I went down at 30 mph was on an upright in a Criterium. It ain't fun. It is less fun at 60+

Sorcerer

Mark Cavendish, to the best of my knowledge, is running Roval clincher rims with inner tubes. He is currently the fastest man on a bike.

In this case, tubes for the win!

There are all kinds of tire set ups in the TDF peloton this year. It's interesting to see. Certainly it appears that tubulars are still relevant as well.

Respect for clinchers with inner tubes is deserved. I think on my summer bike tour I will be using inner tubes despite my preference for tubeless, because I feel that they will be easier to repair in a field situation.

Lazyass

His entire team is running clinchers now and I'm sure the mechanic is loving it. Turbo Cotton open tubulars with latex tubes. Open tubulars are the only clinchers I buy but I still prefer tubulars myself.

Open tubulars do have super tight beads and on those aero rims they're probably hard as hell to mount for the average Joe.