DrIsotope

Here we have a 700x35 Panaracer Gravelking SK, which has been hanging from the ceiling of my workshop for over a year. Note how I have to use special tools and techniques to remove it.



I mean, this isn't conjecture from down at the coop, but I think it goes toward proving a point.

La Tortue

Yep, I get your point. I use the same special tools and solvent as you do and it rolls off the same way.

unterhausen

one of the guys at the lbs jokingly told me the proper way to mount a tubeless tire was to pump it up until it blew off. Sounds like the OOB bike shop the coop bought out might have used that same technique. Not sure how you get sealant all over everything under normal procedures.

MattTheHat 

DrIsotope

trailangel

I'm having good luck with Finishline Multiseal on 2.25 MTB tires. Doesn't dry up. I had it in tire for 5 months and still all liquid when I took tire off.

cyccommute 

DrIsotope

I've been very tempted, as we have this thing with summer heat-- but I've also read, and been told by several people that it simply doesn't work above ~50psi. One of the mechanics at the LBS tried it in 700x25, got a puncture, and it just blew all 2oz right out the hole. I want it to work so, so much, because it would be nice not to go through almost 2 quarts of sealant a year (5 wheelsets!)

Please, please stop editing your posts right after you make them. Beyond that, dude... let it go. You don't know what you're talking about, and the sheer force of your lack of knowledge on the subject keeps generating gifs.



I honestly don't know what your problem is with tubeless. You don't like it, that's fine. But is it absolutely necessary to cloud every single thread in which the word "tubeless" occurs with your own brand of misinformation?

BlazingPedals

A tire with a tube in it could have blown off the same way, given the same... whatever did it. Which is to say there's nothing special about tubed tires that would have prevented a blow-off. I guess you can rule out pinched tube, at least.

cyccommute 

BillyD

If you guys can't get along then maybe somebody should move along.

u235

I've had a lot of dried sealant all over my seat tube, pump, front der cable (bottom pull with pully), rear blinky and under seat bag. Came right off the first time I washed the bike. No different than the dirt and gave it no thought. It was Stan's if that matters. I'd think anyone that ever had a big leak experienced similar. Sticking to a pourous rough rubber tire is not the as smooth painted metal. An example... No one ever has had a hard time cleaning or removing liquid or dried latex sealant from their rim.

Ferrouscious 

I have those tires. Before I got them, I looked them up on the Googles and I got some mixed reviews. The reviewers said they were great right up until fourhundo to sixhundo milés. They would supposedly blow right off the rim. I personally have not ridden 4-6 hundo milés on the tires (they are winter tires only). My 25/28 tires [25 being width, 28 relative volume (that's how Spesh markets them)] say 85-95 psi on the sidewalls.

CliffordK

I've wondered if there is any fundamental difference between running tube tires or tubeless (or tubes in tubeless tires).

Obviously tires remain inflated and stay in place due to a difference between atmospheric pressure outside of the tire, and inflated pressure inside the tire. If somehow one increased the air pressure between the bead and rim, there would be nothing to keep the bead from floating around. Nonetheless, that wouldn't really occur in a properly sealed tire.

And, my experience with tubeless so far (23mm), is that the tire fits tightly on the rim.

There are two factors with tire pressure and tire sizes.

PSI measures the outward pressure of the air on the tire, and is independent of tire size. So, having a bike tire or a truck tire at 100 PSI, the outward pressure is the same.

However, tire size apparently affects the stretch on the sidewall. So, the larger the tire at the same pressure, the more stretching force one puts on the sidewall and the bead.

I can't find the formulas at the moment, but they're on the web somewhere.

Ahh... LaPlace's law.
Pressure

So, as far as I can tell, the surface tension on the tire sidewalls vary with the cross sectional circumference (I think).

Anyway, if one has a 23mm tire at 100 PSI, and a 32mm tire at 100 PSI, then the sidewall tension of the larger tire should be 32/23, or about 1.4 times the sidewall tension. I think Thankfully I'm not an engineer.

This means that the bead interface of the 32mm tire must be 1.4 times stronger than the 23mm tire if the pressure is the same.

pvillemasher

You guys who run tubeless must get a lot of flats. I get one maybe every 1,000 miles or so max, 3 or 4 times a year.
From what I read in this thread about sealant, and from what I'm seeing in the videos in this thread, ain't no way it's for me. Jeez.

motrheadsroadie

CliffordK

I don't quite have 1000 miles on the front yet, but so far no flats, no leaks, and haven't re-pumped it yet.

But, yes, that is about what I get, one flat every 1000 miles or so... perhaps a half dozen a year (including a couple of bikes, trailers, etc).

I have to wonder how long until we start seeing some heavy-duty road tires coming out in tubeless.

Perhaps some vendors are waiting for others to shake out the problems before putting their flagship tires out as tubeless.

Perhaps the Gator Hardshell in tubeless?

They're coming. Perhaps in a decade we'll all be asking what tubes are

Very few car tires in the USA from the last 10 years take tubes, and most of those would be very vintage tires.

GlennR

I have 32mm Bontrager AW2 tires on Zipp 30 Course and run 60 front and 65 rear.

DrIsotope

Schwalbe Marathon Almotion is a step in that direction. It's a shame they're one of the most expensive non-fat tires you can buy. I paid a fair amount less for the tires on my car.

I don't get the tubeless-resistance of most of the big manufacturers, particularly Continental. Goodyear looks promising, but they're nearly as expensive as Schwalbe, who set the bar for absurdly expensive tires.

MattTheHat 

You know, that's an excellent point. Pressure is pressure.

-Matt

ericpmoss

I buy into Mavic's line on tubeless -- it's all about tolerances. Certain Velocity rims are notorious for being a bit undersized, which makes tire installation (too) easy. Slightly undersized tire beads work well in that case, but most tires blow off if run tubeless at pressures above 'soft'. Automobile wheels and tires are far more reliable in this regard, partly because of standards and partly because of much wider, thicker surfaces that seal. The bicycle industry is not nearly picky enough about tolerances between brands, IMO.

I'm not allowed to post URLs, so wind your way to

engineerstalk dot mavic dot com/en/road-ust-tubeless-bike-wheels-easy-safe-fast/

chaadster

This is a lot of threads for something relatively simple to understand: if the tire did blow off the rim, there was either excessive pressure or a bead/rim failure.

The big question is whether the tire, a 32c Specialized Roubaix Pro 2Bliss, was, in fact, under spec pressure, which @MattTheHat says is indicated as 115psi on the sidewall, but which Specialized publishes as 90psi max. Was the sidewall marking double-checked, Matt? It's curious, because 115psi is the listed pressure max for the Roubaix Road Tubeless 23/25c, so given the silly nomenclature, it seems possible that reading the specs, one might easily mixup the tires' max pressure rating.

If a max pressure mixup ocurred, then overpressurization is the culprit.

If the RP2bliss was not overinflated by 10psi or so, then either the bead failed allowing air to push out, or the rim yielded, allowing the bead to be pushed out. Either way, the tire and rim should go to the LBS for inspection.

It's certainly possible, if unlikely, that Specialized erred by printing the wrong maximum inflation pressure on the 32c RP2bliss, but that just takes us back to the overinflation scenario.

jimincalif

Maybe Specialized has recently revised its max pressure spec for these tires? Matt's tire might have been produced prior to this?

MattTheHat 

Nope, I definitely made a mistake on the sidewall pressure rating. The 115 PSI number was for the Continental GP4000SII 28mm tire which I put on the bike after the Roubaix Pros. The pressure on the sidewall matched the pressure shown on the Specialized page I quoted earlier: 75:95 PSI. I examined the tire very carefully. I found no damage on the tire at all, not on the top part of the tire, not on the sidewall, not on the bead area, nothing.

So, yes, the tire was run slightly over pressure. But when left over night, the tire was not over pressure. I'm not sure what it would take to blow the tire off the rim, but my gut feel would be something like 150% of the max pressure specification. I'm surprised the tire blew off the rim at all, having not been inflated over 101.5 PSI. I'm definitely surprised it blew off at 90 PSI. And I'm surprised that it blew off just sitting there at a lower pressure than while being ridden under load at the higher inflation. Lots of surprises for me.

I'll retire these Roubaix Pros out of caution. I'll eventually give tubeless another shot when I find some other tire that I want to try.


-Matt

Rayzorx