I agree with this. But if the decrease in volume (say, upon striking a big rock) is incredibly rapid, I wonder if there would be a very short instantaneous increase in psi from the pressure wave caused by the impact?
Still says the Vittoria Corsa Pro or Vittoria Corsa to me with link to the Corsa Pro, not Corsa Pro Speed.
I guess this does touch on the problem with people putting unsuitable tyres on hookless rims. Several of the big tyre manufacturers have tyres that are both compatible and not compatible with hookless using a very similar name - e.g. the āstandardā GP5000 that a former team mate used on his hookless Zipp wheel. Pretty sure Vittoria and Pirelli have similar. So if youāre confusing the Corsa Pro Speed with Corsa Pro, odds are people are putting those non-compatible tyres on hookless rims.
That said, good work, always nice with more data with the protocol clearly laid out.
Moreover, there is a potential for transient localized stresses in the tire rim interface which is the weak link in a hookless setup. This would require FEA to model a test with perhaps not great accuracy. In a hooked system, these are all managed by (shocking) the hook lol. Letās not forget the failure mechanism is the increased force in the interface due to air pressure, but other forces could contribute too such as hitting a rock, pot hole or hitting the wheel system during a crash.
All said and done, no hookless on a road/TT bike for me, thank you very much.
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It took a sec for Discourse to sync with the homepage article.
And I agree with you 100% . Education is the name of the game. And yes it can be really confusing.
Thereās so much pressure in this thread.
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i donāt know why putting 110psi or 120psi in a hookless wheel would void the warranty. one of the reasons for hookless is you have the freedom to make a stronger - not weaker - sidewall.
eric has taken a big step forward. even if you or jeroen or whomever have a problem with him he has done what others did not. because he now has a testing rig for this he can go further if he wants. if the testing rig were in my garage i would perform a series of tests over weeks and months, taking my time, and adding time to the data. pick 1 wheel. any wheel from zipp, enve, cadex. put a conti 5000TT and a corsa pro speed, whatever, on that wheel, pump it up to 110psi every day for 3 days, and you have a 72hr test designed to ferret out any incremental stretch over time in a tireās bead. you can do a couple of tires a week. publish the results every monday. keeps you and me coming back to the site 
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when i was a bike maker we tested. we did ballistic testing. we did fatigue testing. we SPECIFICALLY and INTENTIONALLY exceeded the limits of the tech in order to find the capacity of the tech and EVERY manufacturer does this. i donāt see how a magazine that performs a test like this could be liable if some idiot says, great, iāll exceed the limits of my equipment because a magazine did that for testing purposes. i certainly donāt see how the manufacturer could be exposed. whereās the cause of action here?
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weāre talking a very rapid increase fromā¦ 68psi to 68.5psi? i question where thereās a model or a thesis whereby this is a thing.
I not meant you as a person or Eric as a magazine host. I meant in a way as where a regular customer buys wheel brand X, does the test like you suggested although that tire is not listed as being approved for that wheel. And then you would ride it and shit happens. Will you liable in that case?
Jeroen
With the caveat that I am not a physicist, my thoughts are that when you very, very rapidly strike a large object with your tire, that impact itself would itself create an air pressure wave within your tire that was far greater than a 0.5 psi increase. And that pressure wave would propagate, after which the psi increase would then return to near the original psi. And this would all happen in a fraction of a second.
But to know if this happens, and to what degree, this would have to be quantified before anyone could say that this might be a factor in tire blow off accidents. And, in bicycle tires, I doubt that it has been quantified.
To be honest I am not sure I want to find out.
āany system failure occurring while riding your bike within the intended use of your Zipp productā is covered.
Not sure going past maximum pressure clearly stamped on system is āintended use of my Zipp productā.
I love testing $hit, so if you send me a wheel Iāll gladly try. I have GP5000 TT tires, 25 and 28. And the new Archetype
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Is there any evidence that a hooked rim would have retained the tire under the same conditions? It seems like the only type of tire that would have stayed on would have been a glued-on tubular.
Not that I know of. In this case, itās pretty clear he hit something big and smashed his wheel.
Not claiming any knowledge about air pressure at all, but in being involved in the design of other safety equipment Iāve seen plastics stressed in ways that donāt make sense at all from sudden impact forces. Overlapping layers suddenly compressing, warping, and jumping out of position in a way that you wouldnāt think possible, but itās clearly seen under high speed camera.
So I definitely buy the argument that a sudden dramatic force can create shock that a gradual sustained one doesnāt.
I do think this test is a good example of most usage cases the product being more than safe enough.
But the fact that the activity we engage in is already right up to the limits of safety, that that extra margin of error reassures or lack thereof scares me.
Iām also confused by the wheel picture. If the tire came off, why is it seated on the broken rim now? It feels like the anti-hookless people are praying for evidence of blowouts with stuff like this.
One of lifeās big mysteries huh 
This is the video he posted the day before in the hospital (it was a story ) So itās gone now.. I will say this to give Big Metz all the benefits of the doubt. And defend any sort of negativity towards him or the situation.
#1 Itās really hard to remember what happened in situations like these.
#2 When you lose all your tire pressure you 100% go onto the rim. And that is what he could simply be meaning as he said.. āThe tire falling off the rimā
This is not a thing. The air in a bicycle tire is compressible and close to ideal. The equation of state is considers pressure, temperature and volume. The only variable that relates to āsudden impactā is volume (not time). The volumes that would impact the tire volume exclusively are too small relatively. Thatās not to say a rider canāt hit a big volume - its just at that point, the system and outcomes have nothing to do with the behavior of the air in the carcass.
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Nothing blew off at 120psi and weāre worried about 70? Iād say case closed. What am I missing here?
This makes absolutely no sense.