Adventure Cycling Association Forum

Bicycle Travel => Gear Talk => Topic started by: HikeBikeCook on February 28, 2022, 10:32:38 am

 
Title: Tubeless versus Tubes - how well do tubeless hold air?
Post by: HikeBikeCook on February 28, 2022, 10:32:38 am
I just built out a new set of wheels (actually had these built professionally) to incorporate my new dynamo hub. I decided to go tubeless with this build since that seems to be the trend. I was super happy with the weight savings - 1.8 pounds lighter with the new hub.

I now have two sets of wheels for my Surly Disc Trucker - the original set with tubes and a tubeless set. The rims are Velocity Cliffhanger 26" which are tubeless rated and the tires are Surly Extraterrestrials - also tubeless rated. Schwalbe does not make a 26" tubeless. The tires were mounted with Stan's and the bead set with a tank air compressor.

Anyway, I have not put air in my tubed tires since last fall and they are still holding pressure, while the tubeless manage to hold air for a little less than a week. Since it is the dead of winter in New England I have only ridden about 20 miles on the tubeless and have added more Stan's a few times now. I am waiting for a warm day to put them into a tub of water to trace any leaks.

My question is - is this normal for tubeless tires to be losing air so fast?
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: Iowagriz on February 28, 2022, 07:57:27 pm
No experience with road tubeless, but I've run mtb tubeless for over 10yrs.

Yes, checking pressure weekly is part of the deal. MTB runs a lower pressure (23), so I imagine the higher road pressures lose more air and might be more quickly noticed.

Side note, I seem to lose more air in the colder temps. No idea why.

Sent from my SM-N975U using Tapatalk

Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: HikeBikeCook on March 01, 2022, 06:32:17 am
No experience with road tubeless, but I've run mtb tubeless for over 10yrs.

Yes, checking pressure weekly is part of the deal. MTB runs a lower pressure (23), so I imagine the higher road pressures lose more air and might be more quickly noticed.

Side note, I seem to lose more air in the colder temps. No idea why.

Sent from my SM-N975U using Tapatalk

Thanks, that makes sense since these have been in my basement, which is cold, and are now in the garage a week at close to freezing. The tires are 26X46 and I pumped them to 60 lbs. (the limit) hoping to push the sealant into and voids.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: driftlessregion on March 10, 2022, 06:11:21 pm
Yes, tubeless tires lose air faster. A small price to pay for the benefits.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: HikeBikeCook on March 11, 2022, 03:19:23 am
Weather has allowed me to ride outside these past few weeks and the tires are holding air much better. Now air loss on the front over a week and only a 2 lb. loss out of rear out of 60 lbs. Now happy I switched.  :)
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: wildtoad on March 12, 2022, 03:18:11 pm
Glad to hear that your setup has improved re air loss. That mirrors my experience w/ road-oriented tubeless, it can take a few rides after initial setup to get to the point of "acceptable" air/psi loss. But you will lose psi faster than a butyl inner tube setup. Cool/cold weather can also prolong that initial sealing process depending on your sealant. For example, I really like the Panaracer sealant as it's the best I've used for sealing so-called "supple" tires, but it's not the best choice (or even a good choice) for cold weather.

I think tubeless is a great option for wider tired touring bikes (I run 650b x 50mm actual) running "moderate" psi.

Still skeptical re it's application for narrower tires/higher psi (28mm and narrower). I experimented last summer w/ 700x28 tubeless tires on one of my go fast road bikes...tires and rims both optimized for tubeless. Setup was easy (tires seated w/soapy water and regular floor pump) and performance was fine throughout the summer. Was running mid 70s psi or so; air loss at higher psi was on par w/ a latex inner tube. Did have to refresh the sealant more often than I anticipated, not sure why. For this season, I am going back to my regular clincher + latex tube setup on that bike; it's lighter than the tubeless setup (I get to play weight weenie on this particular bike) and I can do without the sealant hassle.  I expect things will continue to improve in the roadie context as the big tire makers continue to pour more $$$ into road tubeless.

Happy riding.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: HikeBikeCook on March 12, 2022, 03:40:51 pm
The one thing I am finding frustrating is the available choices of tubeless tires in the 26" size. I went 26" to match my wife's need to run 26" for stand-over and only wanted to deal with one tire size while touring. It looks like the Surly ET's are about the only game in town. I was hoping to ride more like a 40-42 instead of a 46 and the road noise was more than the stock Conti's it came with. I am hoping the road noise will lessen over time as the sharp corners of the tread wear down. I think it has after the hundred miles I now have on them. The first time I road them people on the bike trail turned their heads as I approached since they heard me coming.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: ray b on March 12, 2022, 03:44:43 pm
Sold on tubeless with sealant for off-road riding - especially at lower pressures.

On the road, I'm less impressed, as I generally have fewer punctures, and the seemingly mandatory use of sealant to maintain air pressure (the crux of the question raised in the thread) adds an unwarranted layer of complexity. Will re-visit tubeless for <30 mm tires when sealant is no longer necessary to avoid a lot of tire-pumping every morning on tour.

One more image for those with money. I'll admit that in inexperienced hands, rim cement/tape rivals sealant for creating a mess, but at what point do my fastest rims and tires move from tubular ("sew-ups") to tubeless? (Yes, I still occasionally get to enjoy that hum from high-pressure tubulars on a good road.)
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: HikeBikeCook on March 12, 2022, 03:58:59 pm
Having run sew-ups many years ago I have absolutely no desire to return to them. With my tubeless now holding air for at least a week I would have to say the hassle of tubeless is far less that that of sew-ups and may proves less than tubed tires. The tubeless sealant pretty much wipes off.

I recall the tubular glue building up and having to be scraped off and once leaking in my under seat bag. I also had the joy of almost rolling my front sew-up off the rim on a sweeping corner during a fast downhill. Operator error, I was in a hurry and had done a quick tire change and did not let the glue setup properly. Scared the crap out of me.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: froze on March 20, 2022, 08:50:55 pm
I just built out a new set of wheels (actually had these built professionally) to incorporate my new dynamo hub. I decided to go tubeless with this build since that seems to be the trend. I was super happy with the weight savings - 1.8 pounds lighter with the new hub.

I now have two sets of wheels for my Surly Disc Trucker - the original set with tubes and a tubeless set. The rims are Velocity Cliffhanger 26" which are tubeless rated and the tires are Surly Extraterrestrials - also tubeless rated. Schwalbe does not make a 26" tubeless. The tires were mounted with Stan's and the bead set with a tank air compressor.

Anyway, I have not put air in my tubed tires since last fall and they are still holding pressure, while the tubeless manage to hold air for a little less than a week. Since it is the dead of winter in New England I have only ridden about 20 miles on the tubeless and have added more Stan's a few times now. I am waiting for a warm day to put them into a tub of water to trace any leaks.

My question is - is this normal for tubeless tires to be losing air so fast?

I just love that word...trend...it's sort of like saying the new trend is to jump off a cliff, let's go do it because everyone else is!

I'm assuming that your Surly Disk Trucker is for touring purposes since that's what it was built for, and I assume you want to tour, or bike camp on it.  Here's the deal, since you already have both tube and tubeless wheels I would use the tubeless for local riding, and then switch to the tube wheelset when you go touring or camping, why as you scream bloody murder at me?  On a tour you ARE going to have a flat, it's the name of the game, which means you will end up putting a tube in the tubeless tire, so if you're going to eventually put a tube in it you might as well start off with tube tires.

Tubeless setup is very low maintenance when all goes well, however, the bead is very tough to seat and to break when your hands are tired from riding all day.  Not to mention you will need a special pump inflator that can pump the blast of air needed to seat the tire, and as far as I know at this time, they're too big to be carried on a bike, they're for home use only and not on the road use, so you would be forced to install a tube.

Tubeless tires are a pain to put on rims, that is on purpose so as to seal better, but if you're on the road and have to put a tube in you will need a good set of strong tire irons to get those buggers on the rim.  A VAR Tyre lever is a fantastic tool that fits into most seat bags and works extremely well with tubeless tires, combine that tool with a pair of Soma Steel Core tire levers and you can put any tire on.

Tubeless are a bit lighter than tube tires, that is true, but that is only with one application of 2 to 3 ounces of sealant, once you put in more than one application then the tubeless tire gets heavier and heavier with each application, after the first application your tubeless tire is heavier than a tube tire.  A 105 gram (3.7 ounces) 700x38 tube weighs almost as much as the sealant weighs, put in another application and its way over the weight of a tubed tire.  You need to replace that sealant about every 3 months.  The tubes I use in my touring bike are ultralight tubes and weigh 105 grams, I went with ultralight tubes since the tires (Schwalbe Marathon Almotion) are supposed to be very flat resistant, besides, I've found no difference in flat protection from a heavier tube to an ultralight tube, so why bother with the extra unnecessary tire weight?  The tubes I use are the Schwalbe SV18 in case anyone was wondering.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: dkoloko on March 21, 2022, 10:04:19 am
One addition to the comments by Froze. Lighter weight is not the prime advantage of tubeless tires over tubed. It is being able to lower tire pressure with no diminution in performance.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: staehpj1 on March 21, 2022, 10:07:50 am
I'm assuming that your Surly Disk Trucker is for touring purposes since that's what it was built for, and I assume you want to tour, or bike camp on it.  Here's the deal, since you already have both tube and tubeless wheels I would use the tubeless for local riding, and then switch to the tube wheelset when you go touring or camping, why as you scream bloody murder at me?  On a tour you ARE going to have a flat, it's the name of the game, which means you will end up putting a tube in the tubeless tire, so if you're going to eventually put a tube in it you might as well start off with tube tires.
I would question that logic.  I typically get quite a few flats on a long tour out west in goat head country with tubes.  I have not used tubeless on tour, but my MTB experience with it would make it seem fairly that I would be likely to get by with not needing to ever install a tube on most tours even months long ones.  I know that I have yet to get a flat on my tubeless setup in a period of time where I would have had dozens if not scores of flats with tubes.  I am not counting the times when i noticed that the tubeless setup was starting to lose air a bit quicker and needed to have more sealant added.

I would be willing to put in a tube once in a great while with a tubeless setup rather than deal with many goathead thorn flats. 

Quote
Tubeless are a bit lighter than tube tires, that is true, but that is only with one application of 2 to 3 ounces of sealant, once you put in more than one application then the tubeless tire gets heavier and heavier with each application, after the first application your tubeless tire is heavier than a tube tire.
I am not buying that unless you are talking about applying additional liquid from the start and even if you need to do that it is because you are losing sealant.  My best guess is that yes there is some weight gain as sealant is added, but the sealant weight is lost in two ways.  First some sealant is lost through whatever holes are being sealed or whatever is lost through poorly sealed beads or burping (burping not likely an issue on the road).  This accounts for at least some percentage of the lost sealant.  I am pretty sure the large majority of the weight of the sealant is water.  The water is lost in one way or another or else there would still be sealant sloshing around.

Some water is undoubtedly lost leaving solids behind, but the amount is quite small compared to the total sealant added.  I am not saying it isn't a factor at all, but for most tourists it is certainly noise level stuff and even for weight weenies it probably isn't a major concern.

Okay so, I held off on sending this while I did a very quick and dirty experiment.  I soaked up 10 grams of sealant (Stans, wells haken) into a couple paper towels and dried them out in a warm oven.  I couldn't get a read on how much weight was left in the paper towels because it was less than the rounding error due to the scale not reading to tenths of a gram.  Dry weight of towels at start 4g, weight of towels after soaking up 10g of Stans 14g, weight of dried towels again 4g, calculated weight of solids left 0g.  Obviously there were solids left but they were less than the margin of error of the experiment.

The little experiment can't give a real number, but it seems to show that once the water was removed there wasn't a large amount of weight in solids when compared to the total weight of the amount applied.  I can think of ways there could ba a gram or two grams of error in the little test, but for sure it demonstrated that most of the weight was water.

I'd expect that it would take a major part if not all of a quart bottle of Stans and maybe even more to yield enough solids in your tires to equal the weight of you 105g (3.7oz.) tube if added over the course of normal usage, not that you'd likely add that much in the life of a road tire.

Also even the amount you add to start with is probably only there at the begining.  By the time you add again most of it is gone so the average is somewhere in the middle.  If you add 3-4 ounces of sealant in a new tire IME you lose a good bit while it is all getting seated in.  You may even need to put is a double dose because the tire is getting seated.  By the time it is fully seated and settled in you likely have less than a normal starting dose (maybe half?).  Then you lose a little with every puncture sealed.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: staehpj1 on March 21, 2022, 10:17:05 am
One addition to the comments by Froze. Lighter weight is not the prime advantage of tubeless tires over tubed. It is being able to lower tire pressure with no diminution in performance.
That and an effectively more supple sidewall yield a lovely ride feel.  Something that may not be valued by many, but is a joy to some of us.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: HikeBikeCook on March 21, 2022, 10:32:27 am
Now that I am riding outdoors on a regular basis my tubeless tires are holding air about the same rate as those with tubes. I lose about 1 to 2 pounds per week and some of that may be due to the cold nights we are still having in New England, since my bike hangs in an unheated garage. Yes, the bead was difficult to set originally, mostly due to the fact the tires were shipped folded, and I did use a compressor. But the bead was no tougher to get on or off than that of my tube tires, in particular those 160 PSI tires on my Litespeed.

I weighed the wheel sets after adding a generous amount of sealant and noted the weight saving AFTER the sealant was added.

I said the tubeless is the new "trend" because more and more manufacturers are making tires and rims tubeless ready. Touring bikes have benefitted from mountain bike technology over the past twenty years and it seems that mountain bike evolution is having more of an impact on touring bikes than the road bike evolution IMHO. There have been numerous posts on this site discussing 3X, 2X, versus 1X for touring but the "trend" to 1X came from the mountain bike side of the industry, as has the "trend" to tubeless tires.

It would seem to me that when long distance mountain bike travelers are singing the praises of tubeless tires maybe long distant bike tourers should take notice. If I am 30 miles from nowhere on a mountain bike I need to fix my issue or hike out. On a touring bike, if I cannot fix my issue I can hitch hike to the next town or even call AAA these days. :)

Yes, I am going to carry a tube as back up, but I would rather carry one spare than three -- 2 in the wheels and 1 in my pack.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: froze on March 21, 2022, 09:50:35 pm
If you have the right tires you won't get flats from goatheads, I know this because I use to live in the Mojave Desert of California.  The only tire I found back then that worked, after trying many tires, was the Specialize All Condition Pro, never had a flat with those, but since that time a few other tires have come along that would be virtually flat free as well.  You may have had a lot of flats with goatheads, I don't doubt that, but the blame for those flats was your tires that were not up to the task.  I've done some loaded camping and with Schwalbe Marathon Almotion tires, which are not supposedly as good against flats as the Marathon HS 440, but I haven't had one flat yet.  I opted for a lighter tire knowing I was raising the risk of getting flats, but I don't want to be touring on 960 gram tires, the Almotions are around 625 grams and have a lot less rolling resistance than the HS 440's.

Your experiment was flawed, the tire is a sealed tire, there is no place for the liquid to evaporate away like with the paper towel thing you did.  On top of that, a small pin hole prick would probably only leak out maybe a gram or two at the most, so you would have to have a lot of pin prick holes to lose 3 or so ounces of sealant, and no one gets that many holes.  The sealant will dry out inside the tire, but what state does it leave when it dries out? sticky patches, and or dried CLUMPS of cured latex, the stuff is still in the tire, it just turned into another state.

At the end of the day you have to do what you think is right for you, for me, I don't want to deal with trying to reseat a tire on the road because you can't so I have to carry a spare tube or two, I have to do that anyways whether it's tube or tubeless.  And with using the right tires flats would not be all that common if at all.  Of course, the argument would be that using the right tire you wouldn't get any flats in a tubeless either, and that's true!  But if you do have one, it's more of a headache with a tubeless set up.

Another disadvantage that I forgot to mention is that the sealant is known for clogging valves.

I think the weight thing is false between the two types, by the time you add in sealant, special rim tape which is heavier than standard tape, you're pretty much a wash.

Running lower PSI using tubeless increases the chances of damaging the rim.

Removing a tubeless tire after the sealant has dried will leave you with a sailor's mouth, although if you use a C clamp you can break the seal easily enough.

Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: staehpj1 on March 22, 2022, 10:04:36 am
Your experiment was flawed, the tire is a sealed tire, there is no place for the liquid to evaporate away like with the paper towel thing you did.  On top of that, a small pin hole prick would probably only leak out maybe a gram or two at the most, so you would have to have a lot of pin prick holes to lose 3 or so ounces of sealant, and no one gets that many holes.  The sealant will dry out inside the tire, but what state does it leave when it dries out? sticky patches, and or dried CLUMPS of cured latex, the stuff is still in the tire, it just turned into another state.

This all got me thinking a bit and I looked up what I could find on the subject.  I found an article on cleaning out the crud periodically.  Their claim was that the water evaporated through the casing over time.  I can imagine vapor slowly passing through the sidewall.  Anyway I decided that since my tires on my MTB had numerous applications of sealant and zero cleanings I'd pop them off and check them out.  So far I did just the front one.

It popped off the beads by hand and was super easy to un mount and remount.  Other tires are undoubtedly much harder to mount and remove, but these (Stans Ravens on Stans wheels) are super easy.  I put them back on with my hands and the beads popped on without removing the core before the compressor got above 20psi.  Ithe air barely started flowing when they popped.  I have even mounted them with a hand pump before.

Anyway I popped the tire off and weighed it it weighed 617g (1lb 5.8 oz) including what looked like an ounce or maybe two of liquid still in the tire.  There was some sludge and small lumps.  There was a coating of latex over the whole inside. there was thicker patches of jelly like more watery latex in places.

I scraped and scrubbed until it was bare over much of the inside with a very thin coat of latex over some of the inside.It is hard to judge the weight but a very small fraction of the weight of a latex tube.  Any way the weight after all that was 536g (2.86oz.).  Even if you add a very generous allowance for the coating I didn't get scraped off a 29"x 2.2" tube is likely to weigh more.

I tried to figure out how much sealant I had put in that tire and my best guess is 8 ounces so I figure that a fairly substantial portion of the weight does remain, but nowhere near all of it.

It does seem that if that is a worry an annual cleaning out may be prudent.  Mine had been at six years since first install with no cleaning and some long spells just sitting while other bikes were ridden of I was doing other things.  I would guess that is pretty much a worst case scenario for build up of gunk in the tire.

Quote
At the end of the day you have to do what you think is right for you, for me, I don't want to deal with trying to reseat a tire on the road because you can't so I have to carry a spare tube or two, I have to do that anyways whether it's tube or tubeless.  And with using the right tires flats would not be all that common if at all.  Of course, the argument would be that using the right tire you wouldn't get any flats in a tubeless either, and that's true!  But if you do have one, it's more of a headache with a tubeless set up.
We all pick our poison.  So far lately I have toured with tubes.  I tour ultra light these days and have beem on skinny road tires.  That has factored in and made me lean a bit more toward tubes especially since i don't own a road tubeless setup.

That said any tire I find pleasant enough that I choose it will get flats with some frequency.  In some parts of the country they are quite frequent even with a tire with some moderate flat protection.  Something like a gatorskin is about as far as I go toward flatproof.  Raiding on something like a marathon plus is my idea of hell.

Quote
Another disadvantage that I forgot to mention is that the sealant is known for clogging valves.
Yeah, but I have not found it all that big of a deal.  Just a minor annoyance.

Quote
I think the weight thing is false between the two types, by the time you add in sealant, special rim tape which is heavier than standard tape, you're pretty much a wash.
I tend to think that there is a bit of an advantage, but I am more interested in the supple ride that an effectively more flexible sidewall gives.  that and the protection from thorn flats.

Quote
Running lower PSI using tubeless increases the chances of damaging the rim.
Running too low pressure with any setup does.  Tubeless allows you to go a bit lower.  You get to choose how low you go.  The only thing is that with a tubed setup you get pinch flats when you go low.

[/quote]Removing a tubeless tire after the sealant has dried will leave you with a sailor's mouth, although if you use a C clamp you can break the seal easily enough.
[/quote]
Broke both beads easily with my fingers.  Zipped them off quickly and easily with one plastic park lever.  Easily put them back on with my hands.  I am almost 71 and have pretty bad arthritis in my hands and wrists (especially the thumbs).  My point is that it likely varies pretty widely with the particulat tire, rim, rim strip combination.  The even pop on the rime easy enough that I think I could do it with a mini pump.  I wouldn't want to rely on having to do that and would always carry a tube.

Also my experience is with one particular setup and it is a 29er MTB at that.   So it will likely not directly apply to a bike that I'd tour on.  It may be closer to apply for folks who tour with fatter tired setups.

I wonder about whether the easy seating of the beads on my bike is in part because of the very light sidewall and whether someone who opts for a more robust sidewall would have a harder time.  I'd have expected the opposite, but these tires pop right on every time i have tried them.  Granted they have only been popped off the bead and mounted a few times (mounted when new, popped off to fix a broken spoke when trail debris got into wheel, popped off to check sealant level, popped off today, and maybe some other reason I am forgetting)
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: HikeBikeCook on March 22, 2022, 10:33:15 am
Your experiment was flawed, the tire is a sealed tire, there is no place for the liquid to evaporate away like with the paper towel thing you did....

The sealant will dry out inside the tire, but what state does it leave when it dries out? sticky patches, and or dried CLUMPS of cured latex, the stuff is still in the tire, it just turned into another state.

As I read these two lines they seem to be contradicting each other. -- "No place to evaporate" versus "The sealant will dry out inside" - How is that possible based on the first sentence?
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: staehpj1 on March 22, 2022, 11:19:01 am
Your experiment was flawed, the tire is a sealed tire, there is no place for the liquid to evaporate away like with the paper towel thing you did....

The sealant will dry out inside the tire, but what state does it leave when it dries out? sticky patches, and or dried CLUMPS of cured latex, the stuff is still in the tire, it just turned into another state.

As I read these two lines they seem to be contradicting each other. -- "No place to evaporate" versus "The sealant will dry out inside" - How is that possible based on the first sentence?
I think there is at least some drying.  I believe some vapor escapes through the sidewall.  I don't believe the tire just gain 4 ounces every time you add 4 ounce of sealant over the life of the tire.  I used to believe that most of the weight was water and escaped somehow.  Now after pulling a tire off this morning and weighing it,  scraping it as clean as possible and weighing again, I think the truth is somewhere in between.  Given that I don't know exactly how much sealant I put in or how much latex is left in the tire after scraping I don't have reliable data.  I do have a general impression though.  It is this...  Some goo builds up over time if you keep adding sealant.  Not as much weight as the total sealant you add, but enough to make it worth cleaning out the tire once in a while if you don't wear them out frequently and add much sealant.

I should note this was in Florida.  In the arid southwest they may dry out much more.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: froze on March 22, 2022, 10:15:00 pm
Your experiment was flawed, the tire is a sealed tire, there is no place for the liquid to evaporate away like with the paper towel thing you did....

The sealant will dry out inside the tire, but what state does it leave when it dries out? sticky patches, and or dried CLUMPS of cured latex, the stuff is still in the tire, it just turned into another state.

You failed to read it correctly.  The stuff dried out leaving behind sticky patches and dried clumps, it's still there, it didn't evaporate away into nothingness, is simply dried up into another form.  I'm not sure what kind of example to use, try this one: let's say you have wet concrete, you can slush it around with a hoe, then you let it set for a day what happens to the cement?  You can no longer slush it around because it's hard, hard as a rock, but it's still all there, most of anyways minus some small amount of water that may have evaporated since it's outside, the cement simply dried out, the cement did not vanish into thin air.  I don't know how else to explain it to make it easy for you, but it's not that difficult to figure out what I said.

As I read these two lines they seem to be contradicting each other. -- "No place to evaporate" versus "The sealant will dry out inside" - How is that possible based on the first sentence?
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: froze on March 22, 2022, 10:32:28 pm
Your experiment was flawed, the tire is a sealed tire, there is no place for the liquid to evaporate away like with the paper towel thing you did....

The sealant will dry out inside the tire, but what state does it leave when it dries out? sticky patches, and or dried CLUMPS of cured latex, the stuff is still in the tire, it just turned into another state.

As I read these two lines they seem to be contradicting each other. -- "No place to evaporate" versus "The sealant will dry out inside" - How is that possible based on the first sentence?
I think there is at least some drying.  I believe some vapor escapes through the sidewall.  I don't believe the tire just gain 4 ounces every time you add 4 ounce of sealant over the life of the tire.  I used to believe that most of the weight was water and escaped somehow.  Now after pulling a tire off this morning and weighing it,  scraping it as clean as possible and weighing again, I think the truth is somewhere in between.  Given that I don't know exactly how much sealant I put in or how much latex is left in the tire after scraping I don't have reliable data.  I do have a general impression though.  It is this...  Some goo builds up over time if you keep adding sealant.  Not as much weight as the total sealant you add, but enough to make it worth cleaning out the tire once in a while if you don't wear them out frequently and add much sealant.

I should note this was in Florida.  In the arid southwest they may dry out much more.

You're getting lost on air vs water and what would take place inside a tire between the two.  You know air slowly "bleeds" out of a tire because you have to pump up your tires every day, but if you filled your tire with water instead of air the water pressure would remain unchanged for a very long time as long as there are no leaks, why?  water molecules are much larger than air molecules.  This why fabrics like GoreTex work, air passes through the fabric while the water just stays beaded up on the cloth not soaking through it. 

Most molecules that make up the air are smaller than water molecules (e.g. Ar is smaller than H2O), so it's easier for air molecules to diffuse into a container.  Most things that are "airtight" or "watertight" actually aren't, that is they permit some small flux of molecules. So, the answer comes down to practical considerations, if the leakage is slow enough not to matter for the intended use, then you can say it "doesn't leak". Most people would say that car tires are "air tight", but they go flat eventually, as air molecules diffuse through the rubber, or find their way through microleaks. In some situations, even much slower leaks than this are large enough to matter, in processes involving extremely high vacuum, rubber O-rings can't be used for sealing, because gasses diffuse through them.

That said, water vapor is a constituent of air, so something that is truly 100% airtight is also watertight: it does not allow water molecules to pass.  There are constituents of air that are smaller than water molecules, so presumably there is a hole size that will permit some air but no water.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: HikeBikeCook on March 23, 2022, 11:45:36 am
I guess the bottom line will be proven out at the end of my cross country trip. Since I am traveling with other riders, and one has the exact same bike but running with tubes, we can do a comparison on the number of flats encountered and how often we each have to top off our tires.

For now, at the start, my overall riding comfort has seemed to improve slightly with the tubeless in terms of handling, but that could just be tread difference. I have the weight savings, but that was not the goal. I had actually expected a weight increase because I added a Schmidt SON Dynamo and initially compared the wheel set weights to see how much weight the hub added. I was actually quite surprised and the huge weight savings from the tubeless -- and that accounts for sealant since the tires were sealed when weighed.

If I wind up inserting tubes along he way then I guess the "trend" may not be a good trend. I could also also save a few ounces by bucking another trend and swap my smart phone for a flip phone. :)

I will try and report back here once my trip is complete or if I return to tubes along the way.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: froze on March 23, 2022, 01:25:29 pm
Sun Dynamo for what? recharging rechargeable stuff I assume?  You won't be riding at night will you?  I thought about going that route myself but the cost of the system put me off, by the time you buy the dynamo and then have a new wheel built for it, I axed the idea after doing a lot of research.  A lot of people do use that type of system though, so it is a good system, I just decided to opt to a lower level system than that and went with a backpack type of solar system with a separate powerbank, it's a 3 panel system and combined with the powerbank the whole thing cost me maybe $65 on Amazon.  I've used it a bunch of times and it works great as long as there is sun!  But for days there is no sun I have the powerbank to recharge my stuff with.  The solar system can charge stuff up while riding too, I just tie it down on the top of my stuff on the rear rack and plug into whatever, but so far I haven't had to do that, I usually get to camp by 1pm so I just set it up and start charging, and most of my stuff I use isn't discharged more than maybe 33%, I have a low power usage iPhone SE I use just for this stuff, that phone and any lights I used are being charged at the same time and will take about 2 hours to charge.  That solar thing will charge up my phone as fast as a wall outlet!   

I think the Son Dynamo type of stuff is best for high power devices that drain batteries fast (maybe like for tablets), none of which I have, so the solar/powerbank combo made more sense for me, and a lot of touring people use solar stuff as well, I don't know what the percentage of touring people use one type vs another, but they all seem to be happy with either type.
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: HikeBikeCook on March 23, 2022, 01:51:02 pm
I have backpacked extensively (60 years now) and thru-hiked the AT. I own a multi-panel solar charger as well, but the Dynamo Hub got me a net weight savings plus day-time running lights. I have it paired with an Anker power bank, which the dynamo keeps charged with daily riding even with the lights running. The power bank gives me  the ability to charge my devices for a few days even without a recharge.

I did not consider the cost issue, since I have learned that lighter weight and better tech always costs more than your typical off the shelf stuff. There is always a fine line between lightweight and durability. When you are traveling long distances, over weeks or months, you better understand the reliability and durability of your equipment.

I use what works best for me. It may be more than others can afford, or totally different that what others would choose if cost we no object, but I have no problem with that. I bike and hike to please myself and not to impress others, or try to sell them on my way of doing things. I am always glad to share why I bought something, why I pack a certain way, or how I lace my boots. Not everyone agrees with me or find my methods do not work for them. That is okay! I encourage people to look at many examples and pick and choose the parts that work for their particular needs. I am constantly evolving and adapting based on what I learn from others. I have tried a dozen different pieces of new equipment in the last several months and wound up returning over half of it, either because it wasn't an upgrade to me, or it was lighter but not durable enough.

Like they say in the long distance hiker world - Hike your own hike!
Title: Re: Tubeless versus Tubes - how well do tubeless hold air?
Post by: froze on March 23, 2022, 09:30:25 pm
The newest Son dynamo hub weighs 477 grams according to Schmidt, the solar panel I got weighs 480 grams, so I don't consider 3 grams a big deal, the older Son hubs weigh more than the solar chargers do.

I like the Anker stuff, I got their smallest 523 Slim 10,000mah power bank because my charging needs are small, and it was the lightest weight power bank they sold at 208 grams, and their cheapest.

My only complaints with dynos are they are a more complicated mechanical device, which means something that could break down while camping/touring, the Son nor the Shimano are field serviceable unlike standard hubs; plus, they do have more resistance than a standard hub drawing about 5 to 6 watts when charging and about 2 to 3 when not, that is drag you're always pushing that you're not with solar.

There is more to consider when choosing between the two types.