Caveman Grog

cyccommute 

Here's that video. I wouldn't put too much stock in it however. Operationally, you might get away with it but, generally speaking, the limits set on tires are relatively hard. Some tires...individual and brands...won't take more then the nominal pressure. And, from the standpoint of tubeless, tubeless tires' maximum pressure is significantly lower. See the above discussions for details.





Quibble. The video say that "tires must withstand 8 pounds per square inch" and "this one took more than 20". Both statements make no sense. However looking at the gauge, the units used are bar or 1 atmosphere or 14.5 psi. 8 bar is 116 psi and no dimensions are given for the tire. 20 bar is 290 psi, which is impressive but, as you said, the rims aren't that great a pressure vessel. It's probably not a good idea to try to push that limit by too much since there are a number of other variables to consider.

And, again, tubeless tires have their pressure rating reduced because of the rim/tire interface.

sirkaos

My observations as follows:
When I went from the aluminum rim DT Swiss R470 with Conti's 4000 II (Which a lot of people here swear by and I was very satisfied with), then I went with the Reynolds Assault wheels and 28C Schwalbe Pro Ones tubeless set up.

We have a steep decent nearby that is twisty 6-10%. I improved my times over the decent by about 8 seconds. Which for me was significant. The funny thing is that I thought I was actually going slower on my descents because everything felt so smooth and predictable in the line I chose while descending. I am a big guy and weigh 205 lbs. Very tall on a 64 cm frame, so I would say I have a higher center of gravity that the average serious road biker. In my opinion, this puts even more stress on the rims and tires. No problems at all. I feel very confident with my setup.

Recently I had to send back my Reynolds rear wheel for a repair, and went back to my old set up, OMG what a step down. I noticed immediately less line control on the descents, more rolling resistance, and I had two flats on one 50 mile ride. I ride at 5psi less on the tubeless. I ride very hard on the descents since I need to make up time on that, since I am less of a climber.

aclinjury

it sounds like you love the Pro One, then stick with it. But me, no. I have 4 bikes, and I ride big mountains twice per weekend, and sidewall slashed by sharp rocks is thing I expect to happen. I carry a few tire boots with me for these rock slashes, and saved many people with them. A slash less than an eighth inch on the sidewall of a tubeless tire and it's gone, and even if a sidewall cut seals itself, I wouldn't want to continue riding it once home. It's a lot less painful to throw away a perfectly fine $30 tire with a sidewall cut than a $63+ tire with the same cut.

BlazingPedals

Wow. The lighting was terrible. Was that a mountain bike tire? That would make the test even more impressive. It didn't blow until 220 psi; and even then it didn't blow off the rim, the carcass failed.

Doug5150

In that particular video, I would assume that the script had the units mistake. The announcer spoke of "PSI" when the gauge being shown was in atmospheres. And he said "it must withstand at least eight, ,,, but this one holds nearly 20". Well, it only held about 16 bar. That is quite a bit less than 20 bar, but still far beyond the maximum inflation pressure on the sidewall.

I would generally assume that a tire would need to be able to withstand at least 15% - 20% over its inflation pressure, since if the tire were inflated to its maximum pressure and then loaded with a lot of weight, it could get pushed down "flat" on level ground--at least until the rim caused a pinch flat. So you would expect some margin beyond the amount of pressure increase of being pushed to the maximum sag at maximum pressure.

Companies today don't like to talk about such product limits openly; I suppose it is just a general liability concern. Up until about the 1950's you could find general technical reference books that spoke about this stuff (informally) but after that companies began to keep such information confidential.

A similar question is what is the maximum speed that a bicycle tire can withstand? Battle Mountain streamliners are approaching 90 MPH these days when conditions are good. Production velomobiles can regularly hit 60+ MPH on mild downhill runs.
Informal testing by third parties has shown that most of the name-brand tires can withstand brief periods of over 150 mph.
A few people have build motorized bicycles that can reach over 100 MPH and they use normal bicycle tires, although the couple people I have read of admit that they don't tend to run for very long at those speeds.
I'm 100% certain that all the big bicycle companies have tested at least some of their tires for absolute speeds, but they refuse to state anything publicly.

I have yet to see any information about tubeless tire pressure limits being lower than clincher tires. I would suspect that tubeless limits are lower, if they were using kevlar beads and the clinchers were using steel beads.

DrIsotope

My tubeless tires come in two varieties: the lucky, and the unlucky. Or more precisely, those that live to the point where threads start fraying out of the carcass, and those whose lives are tragically cut short by screws, glass, jagged hunks of metal, etc. I experience nothing in between. I've lost a tire with less than 200 miles on it, and I've had tires last 4,500 miles. I'm currently approaching 30,000 tubeless miles. They're not perfect-- but neither are clinchers, and neither are tubulars. They're also not for everyone. But myself, I would personally much rather spend the time fiddling with tires in the warm and dry confines of my workshop, than out on the side of the road. And in all but a handful of cases, tubeless has been successful.

One afternoon I hit a pothole that was hiding in a shadow-- hit it on a descent at about 35mph. The rim was knocked out of round, and a 2" section of brake track on one side caved in about 1/4". Not only did tire did not unseat, it didn't even lose any pressure. The rim is junked. While I can't say how a tubed clincher would have fared, I have to assume not as well.

I don't waste time on armchair analysis. I don't concern myself with what-ifs. Tubeless works. In my case, it's worth the "hassle." I just swapped a rear tire in about 15 minutes total, from removing the wheel from the bike to putting it back on. It's not that hard. Anyone who thinks it is should I dunno... take up horseshoes. Maybe lawn bowling.

Spoonrobot 

The last few posts have an issue with definitions. Maximum pressure a tire is able to withstand before carcass failure is not the same as maximum pressure before bead failure. It is well known in the mountain bike community that tubeless tires have significantly lower maximum and safe pressure than when tubed. Part of this is the less secure internal bead/bead seat connection and part is that as the inflation pressure increased the side pressure on the bead spreads the rim apart.

Here's an example of a tubeless bead failure: https://janheine.wordpress.com/2017/...road-tubeless/

I'm amazed that he actually did the test, posted it on his site and has left it up. The maximum tubed pressure is 90 psi and the maximum tubeless pressure is 60 psi. Tubeless, the tire blew off at 108 psi which appears to be a reasonable safety margin. What's most surprising is that the tubeless max of 60 psi is held to the same for all size tires of tubeless compatible tires 35mm through 55mm wide. This is almost certainly incorrect as the casing tension on larger tires increases significantly at the same PSI. Guy report in the gravelbiking forum back a few months ago that he had a tubeless 44mm compass tire blow off the rim at 50 psi. It's almost a certainty that this was due to the pressure rating being too high. Stan's rims, which are slightly larger than "normal" tubeless rims, rates the max PSI for 1.7"/44mm tires @45 psi. Smaller normal tubeless rim and 50 psi is right above blow off range, which is what happened.

Anyway, this is all rambling to say that tubeless tire pressure limits are well known to be lower than tubed tire pressure limits.

Metieval

Stan's will come off your frame with soap and water. Reesorting to a 'Solvent' first way of thinking makes me question everything involving the tubeless failure!!!!!

As in if it is 'Solvent' first, then I can assume that more air was the answer to loosing air! like 10 psi loss on a 2 hour ride, so you came home and 'put more than enough' in it so that it would ' be enough' when you went to ride next, but you found your tire blown off the rim.

Now moving past the 'Solvent' way of thinking, since soap and water will remove Stan's from your frame. What do you think soap and water will do to Stan's trying to seal your Rim tabe, bead, blah blah**********?? You know the soap and water you used to mount the tire?

don't take it personal, but I am pretty sure that outside of compatibility issues with tubeless tire/rim, the largest factor in tubeless failure is human failure. This theory is built on the fact that even with clincher tires, a mast majority of the people go over board on PSI, be it bicycles, lawnmowers, trailers, cars, trucks, etc...
E.G tells coworker you probably don't want to be using that 12 point with impact on your lugnut. ""He's don it before" he says, 2 Minutes later $%^$$%#@ it stripped! uh yeah the first time apparent rounded your lugs which is why we don't do 12 points on lugnuts with impact guns. He spent the next hour badmouthing China made sockets and lugnuts.

Likewise I don't think tubeless gets a fair shake.

and then comes the other twist. (for people that commute) people don't commute on tubular tires, so what makes them think that they can commute on a high performance tubeless? like sealant is magic or something?

Caveman Grog

Metieval

Yet a large number of people are riding/racing Hookless bead wheels and doing so tubeless, (lower psi) and Listen...............................?

Do we hear them having problems with Tires blowing off? *Crickets*

Spoonrobot 

You certainly have not been running road tubeless for a decade. There have not been road tubeless tires or rims extant for most of the past 10 years. And this "carbon bead" you keep bringing up only came about in the last year or two anyway. There is a ton of supporting information for tubeless tires having lower max PSI than tubed, spend a few minutes on google. It's obvious from your other posts you already know how to do this.

MattTheHat 

Caveman Grog

Metieval

So we are suppose to believe that you were asking if it was okay to use water (solvent), or if Water would remove your paint?
Edit: I am actually surprised you got your tires mounted with water and soap, and the water didn't desolve your tires first..... /sarcasmoff

alcjphil

Hutchinson and Shimano teamed up in 2006 to introduce road tubeless tires and rims for the public. It is entirely possible for someone to have been riding tubeless tires on the road for 10 years. I am a relative newcomer having only used road tubeless tires for 9 years

u235

Bicycling magazine, 12/2008

No idea of availability back then. Just found a reference because I was interested in timeline.

Spoonrobot 

Based on his other posts in this thread, he may have been using the tubeless systems that were around 10 years ago but there's no way he's been doing it for 10 years. His posts read like someone who had a little knowledge, left the sport and then came back to overshare a combination of things they knew and things found through furious google searching. I don't believe anyone has been using road tubeless for that long, there just weren't rims and tires available.

superpletch

fake news!

tubeless tires are great, if you don't believe me google it.

Caveman Grog

MattTheHat 

No, I was pointing out the irony of you mentioning my "solvent first way of thinking" when the first thing you mentioned was also using a solvent. Granted water is a weak solvent, but the irony is still there.

-Matt

MattTheHat 

By way of update, I was able to take a couple of fairly short rides yesterday after work, both about an hour each. The rear tire only lost about 1-2 PSI on each ride and the front lost about 3 PSI. I'm hoping the tires continue to seal better as time goes by.

-Matt

cyccommute 

There's a momentary bounce of the gauge to about 20 just before the cut to the exploding tire.

I would agree with 15% or maybe even 20%. Double is pushing it a bit for an loaded bike that is moving. The bicycle and rider weight will increase the pressure as will impacts. Momentary pressure spikes could increase the pressure enough to either blow the tire off or rupture the rim.

I would also add that the amount of pressure you can run is dependent on other factors as well. Not all tires are made the same nor can they be run over the nominal pressure. If you look around, you can find details of my long sad saga of dealing with Continental touring tires. Suffice it to say that in my experience they can't even be run at nominal pressure. I've had several blow off the rim at the 90 psi rating.​​​​​​​

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Can you blame them? When you have people suggesting that you can run twice the rated pressure in a tire, companies aren't going to want to cover that kind of liability. Sure engineers over-engineer their products but that's in case something unexpected happens. They don't over-engineer so that people can push the limits of whatever they make. The over-engineering in bicycle tires is meant to take care of unexpected pressure spike but it isn't meant to be a normal operating situation. If you do run your tires at over the limits, what happens when the tire experiences an unexpected pressure spike that pushes it way past the limits of the engineering?

Stan's says in all of its literature that you should never inflate a tire that isn't designed for tubeless over 40 psi. Jan Heine (see post 12 for link) says not to run road tubeless over 60 psi. He also makes the same argument I have made above (I didn't read his article first) about the tire/rim interface being reinforced by the tube.

As for beads, I try to use only kevlar beads, i.e. folding tires...on all my bikes. I haven't noticed a significant difference in the pressure they are able to hold for a tubed tired.

cyccommute 

Yes, water is a solvent but it's just not the right "solvent" for the job. As I said many pages ago, there probably isn't a right solvent for the job that won't damage the paint on the frame of the bike. If you had gotten to the mixture immediately, water would work. But after it has had a chance to dry, it's akin to removing latex paint from a wall. It's not going to be easy.

The latex is in a suspension in the fluid used for the sealant. In this case the "fluid" is a mixture of water and a glycol. Once a tube is punctured and the mixture enters the hole, the fluid is evaporated or dispersed and the suspended latex particles agglomerate and form a polymer. Once formed the polymer is water insoluble...it would be highly inconvenient for the plug to dissolve the next time you ride through a puddle. In fact, the polymer is not all that soluble in much of anything. There are some nasty solvents and solvent mixtures that have limited solubility but you wouldn't want to work with them nor could you easy get the chemicals outside of a laboratory.

Mechanical means is about the only way to strip the latex off whatever it gets on as I said 'lo those many pages ago.

MattTheHat