air isn’t pushing up on the underside of the bead, in a hookless tire. it’s pushing out. the bead of the tire is snugly nestled on the shelf of the rim. the only problem you’d have with hookless is if you put so much air in the tire that there is just nowhere for that volume of air to go.
Air doesn’t push up at the bead but since pressure is perpendicular to the surface, it pushes up at the tread…
At no pressure does air have “anywhere to go.” There is some elasticity in the tire but most added air goes to increasing pressure, not volume. Any amount of pressure pushes up on the tire. For equivalent tire beads, it will take less pressure to push she bead over the rim on a hookless wheel.
All of this is just theory anyway. Weight, safety, etc.
How much weight does a 1mm x 1mm carbon hook add? Back of envelope calc tells me 5-6g. Thats not a benefit when wheelsets of same depths vary 150g+ (1545 g 64mm Roval vs 1690g 58mm Zipp NSW). Great you saved 5g, now add 5g to the bead so it doesn’t blow off.
Same for safety. How many bead related failures have you seen in your lifetime, let alone on modern rims?
Aero benefits of the 1mm lip reduction: also theory whether or not it is a measurable difference.
It just comes down manufacturing cost, and at the moment it limits tire selection. Not everyone wants Schwalbe/Cadex/Cervelo/Hoka. Theoretical and marginal (at best) benefits + real limitations.
Once more brand adopt standards and offer hookless compatible tires, sure. They’ll be equivalent. But even then they won’t offer measurable benefits. Unless the consumer gets to enjoy a lower system cost, there is no point of going through these growing pains to get there.
everything you wrote is absolutely right. until it ceases to be right. i think we’re mostly saying the same thing. you can argue fine dialectical points, about whether the air has “any place to go” or not (the air does in fact “choose” to no longer remain under high pressure, and you know it’s made that “decision” when it pushed the tire off the rim).
i’ve been in the factories, i’ve seen the processes, i’ve spent hours with the engineers and the product managers, and those who’re just working on the factory floors. i was a skeptic, like you, until i made the decision to pay attention to experts who only do this or a living.
we had this very same discussion about disc brakes. then we had the same discussion about tubeless in general. now we’re having it again. we had this very same discussion about 15 or 20 years ago about clincher tires in general (versus tubulars). and 10 years before that we had this same discussion about steep seat angles in bikes. and 2 years before that about aerobars (remember, a really good rider doesn’t need aerobars for time trialing. right?). 2 years before that we discussed whether carbon monocoque bikes made any sense (and many decided they didn’t, for all sorts of great reasons.) 5 years before that it was click shifting.
we’ll have this same discussion in 3 more years, and in 5 and 10 more years, i just don’t know what the tech will be. all i know is, we can take the very discussion we’ll have now, very same sentences, and just change a few nouns. but they all come down to the same complaint: “we don’t need this new tech; the tech we have now is perfectly fine; any good rider can ride current tech.”
the beauty of it is, you can choose to buy whatever wheel you want. you certainly don’t need to buy a wheel with a hookless bead. as of now.
