cyccommute 

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Yes, I know that the sealant dries out but I can see no mechanism for why it would happen. All tires lose air but the sealant isn't "air". It is an emulsion that contains a whole lot of water. Water shouldn't be able to get past the rubber in the tire. Air can but water is a larger molecule and the tire's rubber is very hydrophobic. The polarity of the water is a mismatch for the polarity of the rubber...very much like oil and vinegar.

Perhaps the other components in the sealant are setting up a situation where the mixture is being allowed to diffuse through the tire but that's not a good thing. I have seen some early tubeless tires and early conversions using regular tires which blistered under the tread but I would consider that to be a very undesirable result.


No, that is an opinion. The same could be said about Slime or other sealants in tubes. I don't like flats any more than the next guy but I'm not going to use Slime because it is extremely messy nor am I going to use tubeless because it is extremely futzy. That's also an opinion.

Fix it for ya. Slime in a tube is just the same as sealant in tubeless. The tube is only vulnerable to pinch flats if you insist on running insufficient air in the tire. There may be a reason to run less air in an off-road tire but there is no reason to run so little air in a road tire. Road tires have a much lower profile and lower volume than off-road tires. If you were running them so low as to risk a pinch flat with a normal tube, you are risking damage to the rim.

There is also nothing inherent in tubeless tires that makes them more resistant to flats. Sealant (same as Slime) is added to seal punctures so that you don't have to remove the tire to repair flats all the time. It's difficult to reseat the tire in the field and/or repair the leak. You could just as easily run a tubeless tire without sealant but you might not like the consequences. On the other hand, you could put the same sealant you use in a tubeless tire in a tube and get the same benefit...exactly as Slime and other products do.

And a tube in a tire won't rupture on its own unless the tire is damaged. But a tubeless tire that suffered that kind of damage wouldn't hold air either.

La Tortue

Simply pumping up an old fashion tubed tire to a certain pressure and it staying there is a novel idea. This is probably something more talked about on the couch than actually occurring on the road. I've seen tires burst while sitting in the hot sun, I've seen them change due to temperature changes not to mention perfectly aired tubes explode when unexpectedly coming across inches of raised concrete. Or how about the especially unlucky bloke who's double flat was induced by the metal bollard squares along the Chief Ladiga Trail? Couch talk is one thing but truth is flats happen on the road. The other truth is tubeless reduces those chances of a flat by a whole lot. This is being demonstrated on the road every day.

cyccommute 

Kind of non sequitur but...

Whoever said anything about pumping up a tire to a certain pressure and having it stay there? If bicycle tires were metal, you could expect the pressure to remain consistent but a tire is a semipermeable membrane with regard to air and the rate of diffusion can be calculated using Fick's Law of diffusion. It happens with any tire, tube or tubeless and there is no need for "couch talk". It's known and you haven't discovered anything.

Yes, tires might burst while sitting in the sun but, considering that tubeless tires are run at a lower pressure due to the limitation of the tire, tubeless are more likely to blow off a rim than tubed tires that can take a higher pressure if the pressures are equal as I've already pointed out in post 19 and post 22. That's Charle's Law.

Impact momentarily decreases the volume in the tire and increases the pressure in the tire according to Boyle's Law. Depending on how close you are to the maximum pressure of the tire, that increase could be enough to exceed the limits and blow the tire off the rim. But it would happen for either kind of tire and would happen at a lower pressure for tubeless tires. While you might be able to slam into road hazards without risking a pinch flat, you can still damage the tire or blow it off the rim if you do slam into road hazards. A properly inflated tubed tire isn't going to suffer pinch flats all that often and has less likelihood of exceeding maximum pressure because it has a high maximum pressure.

What? Was this in the National news? You could just as easily damage a tubeless tire on some kind of road debris. You even said that the high mileage guy "shredded" a tubeless tire.

OMG! I never realized that flats happen on the road. I always thought they happened in the middle of the night and were caused by flat gremlins! I learn something everyday on the Bike Forums!

All sarcasm aside, yes, any pneumatic tire can be flatted. Any. It is a completely random event and and there is nothing you can do to prevent it. Tubeless only reduces the flats by using heavy sealant which has to be refreshed for some reason from time to time. You could accomplish the same thing by using sealant in tubes.

La Tortue

Meanwhile, Tarzan (a tube and tire rider) gets another flat while Teeth Grinder, (exclusively a Schwalbe One tubeless rider) continues to roll flat free in their quests to set a new world record for most miles ridden in a year. Ultracycling: Endurance Cycling Records - HAMR

La Tortue

Steve Abraham (Teeth Grinder) provided an interesting response yesterday when his host for the night asked him how many flats he has had. Taken directly from the hosts post:

He's on the red bike, but with the new silver wheels - and the bike is looking good, Everything is as it should be. I asked how many punctures and the obvious answer was "I don't know - they repair themselves" ( ).

Real data from the road is worth more than a gazillion opinions from the couch.

La Tortue

More on Schwalbe One Tubeless tires from Steve Abraham during an interview about his ongoing one year time trial:

"Special tubeless tyres from Schwalbe that self-repair if they puncture and save me lots of riding time. The 10 minutes required to fix a punctured tyre could cost me 3 miles of riding, and I seem to get punctures every one to two days on a big riding day. So I am saving what could add up to a thousand miles of riding by using tubeless tyres."

I'll bet Tarzan goes to tubeless before the year is up.

La Tortue

The facts on the road keep adding up. Did anyone notice this news? Martin Elmiger, Team IAM Cycling, finished 5th in Paris-Roubaix 2015 on his brand new Schwalbe tubeless tires.

DrIsotope

About 1,000 miles on my 700x28 Schwalbe Ones, and I'll never go back to tubes. Do they corner faster, or roll faster, or weigh less than a comparable clincher? Don't know, don't care. But I do know what they do do (tee hee) and that's not get flats (unless you could burbling/spitting sealant for a few seconds whenever you run over something too big,) and ride significantly better than a tubed tire. Because I don't have to run 100+ psi. I run mine at 70psi front and rear, and have done so since the day I installed them. So to any of the couch commandos who poo-poo tubeless never having tried it once, come back when you have some empirical evidence to offset your blind conjecture. Because if you don't think a tubeless tire @ 70psi is going to ride better than tubed @ 100psi... well, I don't know what to tell you. I watch people spend loads of money on shock-absorbing seatposts, carbon this and that, and saddle after saddle, just trying to battle the rough ride brought about by road tires. Doesn't it make more sense to change the source of the problem?

TL;DR: I run tubeless because I don't get flats and they ride a lot nicer.