Here is the question. If I understand hookless correctly air pressure keeps the tire on rim???????

What happens if there is a blow out or sudden air loss? Can the tire come off the rim? I have had a bunch of flats on clinchers but I have never had a tire come off a hook rim and damaged the carbon. Can this happen on a hookless rim?

The bead is unlikely to slip over the rim in the event of a flat. It can separate from the bead shelf and fall to the center of the rim, exposing the rim a bit more to direct contact with the ground. But I don't think it's substantially different than a hooked rim in this regard. Some people claim to have a harder time "breaking the bead" with hookless rims.

A hookless rim, in theory, could be more generally resistant to damage, as they typically have shorter "rim height," and no relatively fragile overhanging hook. And they can have stronger construction. (part of the reason by MTB rim have gone mostly hookless).

I agree that hookless is probably the future, whether it really offers benefits or not. I don’t agree with the “I would be happy with the Enve tire”. That thing is such a turd that you would probably be better off with a non aero rim and decent tire versus the best hookless rim and the ENVE tire.

I think the only passable hookless tire is probably the Zipp, which is just a few watts worse than the GP 5000.

I seem to remember that there are hints of a Continental hookless tire and maybe Vittoria as well. Once you get some better tires, the benefits of hookless will be there. At the moment I find it a hard sell if you are interested in going fast.

Now the really interesting counter example is the Specialized Rovals. They aren’t even doing tubeless. It’s hooks and an inner tube.

What's wrong with the Schwalbe Pro One TLE Addix (other than the long name)? Also just a couple watts off the GP5000.

as you read more and more on this subject, you'll come up against a term of art: fitment. we are aggregating a whole bunch of articles on hookless, and i talk to wheel and tire makers pretty well constantly. this issue of fitment keeps coming up. the ETRTO specs from 2019, which codify everything about the rim shapes, radii and contours, allow the tire companies to build tires that precisely fit this wheel design. the more precise the fit, the more leakproof the wheel is, and the less likely it'll jump the rim.

i've asked this specific question, and what i get is this: best? tubular. of course, in the old days rolling a tire was a thing, and that doesn't happen with hookless beads or, really, any clincher tire. but tubies, when flatted, stayed on the rim if the glue job was good. that's a little tricky with triathlon, because the glue job has to be good but not *too* good, or you can't change a flat in a hurry.

second best? at not jumping the rim? hookless, because the fitment is dialed. the wheel you're currently riding is 3rd best, that is, hooked bead, either tubed or tubeless.

the problem is the lack of tires. the wheel is better. it's stronger, lighter, and the wheel/tire system can be made more aero. much less likely you'll damage your rim with this design. but you take vittoria as an example, i have a call with them tomorrow on this, but the corsa speed TLR, zipp is iffy when asked about the use on the 303 firecrest and S (yes on the 25mm i think, no on 23mm). ENVE is no on both, and CADEX is no on the 25mm, and i'm pretty sure that will mean no on the 23mm.

however, how is the test done? what's a "fail?" example: let's say a "fail" is 1.5x the max stated tire pressure on the tire. i think the corsa speed has 130psi on the sidewall. is it fair to fail this tire if it blows off the rim at 200psi, when another tire passes because it's got 80psi stamped into the sidewall? but you do have this fitment issue with tires not designed for hookless.

tires designe for hookless tend to have stiffer beads. this is especially true with the CADEX tires. i just can't imagine that tire ever coming off the rim except when you choose to take it off. but the one tire - that you know is a fast tire - that is specifically made with hookless in mind is schwalbe's pro one and pro one TT. i think this checks all the boxes.

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Dan Empfield
aka Slowman

Thanks. I'm in no rush to be a beta tester and go hookless but when the world changes in the future I want to be assured that when I get a flat I don't want to worry about my tire flying off.

I'm also betting that this change to hookless will not be any cheaper than wheels and tires we have now.

Wheels are, so far, looking cheaper. (the new hookless Zipp 303-S is cheaper than the outgoing 303).

Tires seem to be a bit more expensive, but not a ton.

you're hookless right now. every pneumatic tire you rely upon is hookless. except your bike tires. and even they may be hookless, if we're talking gravel and fatter.

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. what you'd need is to make sure the tire fits well onto this style of rim, and that the bead is sufficiently inflexible. you're absolutely fine if you use a tire that's made for this tech, and you're less likely to damage your rim, because the rim walls can be made so much stronger.

as to the price, the only thing i can tell you is that the manufacturing process is cheaper. this should, in theory, make it easier to make a rim, which means the barrier to entry to wheelmaking just got lower. which means competition. but i can't guarantee you what will happen with prices.

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Dan Empfield
aka Slowman

To answer your question and the OP: Hookless is very safe. Only issue is the tire selection being quite small (and not including GP5000TL). I run Pro Ones on the Enve 65 wheelset and love it. Enve testing has the 65 at basically the same aero benefits as the 7.8 hooked rim. And, its $950 cheaper with same hubset. What's not to love?

No one is beta testing these hookless rims at the present. They have been used on road for quite a while now. I had a bad TL blowout a few weeks ago when pootly hopping a bad pothole while in the aero bars (on the rear, 2 slices). Immediate loss of air at 20+ mph. No issues slowing down to a stop. Tire stayed in its bead. Felt very safe.

Other option short term is what Roval has gone to with the newest CLX series being nonTL. I have one generation behind CLX40s on a Tarmac and run Zipp Tangente 25/28 TL tires WITH Latex inner tubes. After one week of usage (maybe 75-100 miles), front was still at 60 psi (65 originally) and rear was at 40 psi (65 originally). Topped off the rear and went riding. This is on Latex inner tubes. When mounted inside a TL tire on a TL rim, there seems to be minimal leakdown without adding any sealant. Very happy with both setups.

Wait if you want to on buying new rims since we are heading into the Zwift weather window, but also don't waste your money on 7.8s when the 65s are great.

Thanks, Brian

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"We don't inherit the Earth from our ancestors, we borrow it from our children." --Chief Seattle

Thank you osugasman - going to hold off through Zwift season and log some indoor miles.

Will more seriously consider the Foundation 65s in the spring and hopefully we will have some more competitive options as well!

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.

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Dan Empfield
aka Slowman

All valid points. But I think hookless is different than the other examples, because they have more obvious benefits.

Disc is a measurably better brake at the expense of weight and aero. No matter how much rim and disc were to mature, disc would always brake better and be heavier/less aero.

Tubeless is better with puncture resistance at the expense of mounting/cleanup hassles (for now). Once tubeless matures, it'll be the clear winner because the downsides disappear, it's just not there yet.

Is there any measurable/practical benefit to hookless? The aero, safety, and cost benefits are yet to be proven, and once tested might all round to zero: 0.1W, 1 less failure per 1,000,000 wheels, and $20 (cya: made up numbers)

i disagree with your assertion that the aero benefits are yet to be proven, likewise the strength benefits. however, price? time will tell. tire more likely to stay on the rim after a flat? i have no knowledge of any data demonstrating that.

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Dan Empfield
aka Slowman

Do you have data to point to on this? Thanks.

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http://bikeblather.blogspot.com/

I didn’t care about running tubeless and I wanted conti or Vitoria. I have a set on the new Roval’s on order.

no. every wheel company i've spoken to that makes hookless says the same thing: they changed because, among other things, they can make a stronger wheel that holds up better to road insults. so, giant, zipp, ENVE, and the wheel companies i can't name because they haven't yet finished their hookless road designs. but i haven't seen the data. i'm taking their word for it, and the reasoning they give is sound.

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Dan Empfield
aka Slowman

It's true they do do say it and the reasoning is sound. Since the production is cheaper, it is in their interest to make these statements though. And if it's 0.1W and one additional broken wheel per 10 million miles, it's not a meaningful difference even if there is one.

What’s that old saying from on here?...Oh yeah, “In God we trust...all others need to bring data.” :-)

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http://bikeblather.blogspot.com/

occam's razor. if all the wheel companies are moving over to this tech, and if they all say they're doing so because they can make a better, stronger, lighter, faster wheel, it's unlikely they're all lying. however, you're right, they may well be lying. it may be that cervelo, trek, canyon, all just make up the nice aero charts that they serve us, and none of them are actually real. maybe the moon landing was faked.

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Dan Empfield
aka Slowman

I'm not claiming or even implying that they are lying about those benefits. I'm claiming that we don't know the degree of the benefits. 0.001W saved is more aero. I've broken one carbon wheel in my lifetime when I hit a nasty boulder. Would a hookless rim have a 1% better chance of survival in an equivalent crash? 50%?

If the benefits are 1% then I'd ride hooks until they're mainstream or at least widely standardized, easy to use, and available. If hookless means 5W and bombproof then I'd jump on board much earlier.

When I would have to buy a whole new set of wheels, lets say because I would buy a new bike with disk-brakes, I would at the moment be reluctant to buy hookless because:

1. I would not like to start messing with tire sealant;
2. I would not like pumping up TL tires, because I "heared" you need this "blast" in the beginning, for which you would need a special pump, which could again be a problem if such a pump is not available (underway, in transition zones etc.).

A solution: of course you could put an inner tube in, but that is not the intension of the whole thing, and also I do not know if you can exchange any TL valve with a valve of an inner tube.

that to me this is the big one that needs an answer,
i find it interesting that the two specialized/roval world tour teams moved on to clinchers this season after just a brief stint with TL. claiming that it allows for a lighter total system. but can't find any saving worth writing home about... instead could it be that today's tighter tolerances allow for sufficient failsafe properties for both alpine descending and riding on until the wheel change can be made and are therefore given preference over (less safe?) TL?.
have you discussed this with anyone?

all the wheelmakers that i've spoken to believe that hookless is more likely to stay on after a flat, because of fitment. the wheels are made to a standard that's pretty strict, allowing the tire makers to make a tire that sits on the shelf in a precise way. also, the tires for hookless are made with stiffer beads.

almost no tire company is making a tire only for hookless. the tires will work in hooked and hookless. but if you don't make a tire for hookless specifically, it's not a good idea to use it for hookless. i had a call with the folks at vittoria day before yesterday, and they confirmed that their corsa speed TLR is not made for hookless. yet i've heard it's being used for that. so, when wheel and tire companies say that hookless systems are more likely to resist jumping off the rim, the assumption is that you're using a tire made for use with hookless.

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Dan Empfield
aka Slowman