Zipp "reaffirms" safety of its hookless rims, but now advises teams to use tyres no smaller than 29mm

Now I'm just waiting for Left_Is_For_Losers to wade in with some conspiracy theory that hookless rims are a Socialist plot to take over the world, force everyone to read The Guardian and eat tofu.

Leftist here that's pro hookless and vegan

All to you but I won't run tubeless or even hookless as allthe advantage listed are pretty much constructed to push it (except maybe the sealing).
the wheels are tad lighter but that's set off against the far heavier construction or far less thread. The total wheelsystem is heavier with tubeless. I run 56mm wheels 1290gr at pressures around 4.7bar. Rolling resistance with tpu inners are within margin to tubeless. I use hooked wheels as it gives an extra safeguard but that won't exclude all risks. Most tubeless tires are far less puncture proof then tube tires so the sealing is not that of an issue. I run 18k km a year and flat once a year on average. 
So all those so called advantages are actually mostly disadvantages.
The comparison with discs is a moot point as they are safer for normal cyclist

Zipp most definitely lowered their retail prices upon going hookless. That said, old hooked wheels and tires had terrible tolerances. To the point of occasionally needing 2 layers of cotton tape, to breaking beads with very thin tape. Hookless tolerances are outstanding compared to what hooked wheels were in triple the time

Modern hookless is designed to take advantage of the now known "faster " approach of having wider tyres at lower pressures run tubeless. They are also manufactured to strict tolerances as dictated by the ETRTO before being allowed to be sold to the public. Something not so strictly adhered to on old steel rims. We are judging a technology based off limited feedback and outlying incidents. If there were more incidents to work from for how many products are in use, then it is absolutely something that needs addressing.

I have seen other articles on the matter which have shown the rim in question - the rim is fully split along its depth. I doubt any wheel of any tyre interface would have stood up to that impact.

Matthew Acton-Varian wrote:

Modern hookless is designed to take advantage of the now known "faster " approach of having wider tyres at lower pressures run tubeless. 

I didn't realise you couldn't run lower pressures on hooked rims, I'll have to nip out and put a bit more air in my tyres!

I always thought modern hoolkess is to allow manufacturers to reduce production costs by more than they reduce the sale price.[/cynical]

Nowhere did I specifically say you couldn't run lower pressures on hooked rims. Your cynicism is flagulating and utterly confusing right now.

yupiteru wrote:

we have gone backwards with hookless rims appearing again.  Why?  Just to save manufacturing costs, simple as that. As if they do not make enough money as it is.

This does seem to be a large part of it. I heard that Hambini recently posted a video with cross-sections of rims comparing how little material there is on a modern hookless rim compared to a hooked one.

Like carbon spokes and, to a lesser extent, things like cables/hoses through the headset, these things seem to be sold as "new!", "shiny!" and not really any better. The one thing that changes is that you have to pay a mechanic to work on them due to the complexity and/or fragility of the parts. And it will most likely require a dedicated tool that you wouldn't normally own and can't be used for anything else.

And while I'm not saying people with the money shouldn't buy what they want, I can't help wondering where all these proprietary parts will be after the 'massacre of the SKUs' by Trek (and others will surely follow suit). People buying a secondhand bike will be stuck with parts that can't be replaced like-for-like while the fragility of ~700g carbon frames means that it could be all to easy to put a hole in a top tube or crush a seat stay with a casual knock or fall.

That last option is one of the reasons I don't want to see the UCI's 6.8 kg weight limit reduced. If we try to shave even more weight off a bike just so people can ride up hills 0.1 km/h faster (or simply brag about their bike's weight) they will have shorter lifespan before being dumped in landfill and will be more vulnerable to catastrophic failure.

Simon E wrote:

yupiteru wrote:

we have gone backwards with hookless rims appearing again.  Why?  Just to save manufacturing costs, simple as that. As if they do not make enough money as it is.

This does seem to be a large part of it. I heard that Hambini recently posted a video with cross-sections of rims comparing how little material there is on a modern hookless rim compared to a hooked one.

Like carbon spokes and, to a lesser extent, things like cables/hoses through the headset, these things seem to be sold as "new!", "shiny!" and not really any better. The one thing that changes is that you have to pay a mechanic to work on them due to the complexity and/or fragility of the parts. And it will most likely require a dedicated tool that you wouldn't normally own and can't be used for anything else.

And while I'm not saying people with the money shouldn't buy what they want, I can't help wondering where all these proprietary parts will be after the 'massacre of the SKUs' by Trek (and others will surely follow suit). People buying a secondhand bike will be stuck with parts that can't be replaced like-for-like while the fragility of ~700g carbon frames means that it could be all to easy to put a hole in a top tube or crush a seat stay with a casual knock or fall.

That last option is one of the reasons I don't want to see the UCI's 6.8 kg weight limit reduced. If we try to shave even more weight off a bike just so people can ride up hills 0.1 km/h faster (or simply brag about their bike's weight) they will have shorter lifespan before being dumped in landfill and will be more vulnerable to catastrophic failure.

Given that competition is high and imagination is low, marketing and sales folks have decided that price is the best way to sell product, us, as consumers, are also driving this race to the bottom. Manufacturers have to make money somewhere and if it doesn't come from the bike, it'll have to come from somewhere else.

 I can't help wondering where all these proprietary parts will be

Just wait for the bike carnage over motors/ batteries/ reglators/ screens/ etc for e-bikes! I have watched videos from bike mechanics and reviewers visiting the latest far East tech shows which are largely about e-bikes just for the schadenfreude of hearing about a failed 2020 Bosch motor (on a bike which looks hardly used) which is going to cost £700+ to replace and the multiplicity of down tube fitments for batteries and motors from increasing numbers of Chinese companies where you're never going to be able to obtain replacements. My 'most useful bike ever' battered Vitus Substance cost £650 in October 2019, and is going to be bashing over rough trails pulling a trailer for a long time to come, unless drivers and Lancashire Constabulary succeed in conspiring to eliminate me.

Hookless has been around since before 1900. Hookless tubeless is also very far ahead of where hooked clinchers were in the same period from introduction

Wht hasn't been included in this article is an image of the rim completely cracked that was released by Zipp upon receipt of the wheel.

I don't think many carbon rims of any tyre interface would have survived the impact in question.

Couldn't agree more. I've been running the 303 hookless since they came out without any issue at all running as per their specified tyre width / pressure recommendations.

Lets not forget many of the other teams are running hookless rims from other manufacturers without issue too.

It all feels a little bit like the disc rotor debacle all over again.

As I can't afford the latest tech, I am still stuck on rim brakes so the technology is not familiar to me. But all road rims are subject to the same safety tests (including destructive impact tests), and considering the whole cross-section of rim was destroyed at the impact site, the force of the impact that destroyed De Ghent's wheel was significant enough to exceed those tests. Because of this, it is fair to assume that any tyre/rim combination would have suffered a similar structural failure at impact. A tubular might partially hold its shape more as the glued carcass of the tyre stays mostly in place, but the carbon structure of the rim would still be destroyed. I suspect an alloy rim would have a terminal dent in it, too.

Actual disc rotor injuries were one in a million freak chances too. There have been odd reports of injuries when millions of miles, and dozens of races (from pro to amateur local races) happen almost daily. the phrase "mountain out of a molehill" springs to mind.

Not the same. Disc brakes offer better braking, if it's required is another issue, hookless offers no consumer benefits at all. Also, the existing technology, hooked, will not fail catastrophically given slight overpressure or tyre undersize. Good luck to hookless users, you'll need it.

Exactly, roadies love to make the simple so very complicated, then whine.

It's not just about surviving the impact; it's about the consequence following a rim failure. 

For example, consider the scenes at Paris-Roubaix a couple of years ago: https://road.cc/content/tech-news/two-carbon-shimano-wheels-fold-half-pa...

In both cases, the wheels are horrifically mangled, yet (as far as I can tell from the slightly sub-par videos), the tubular tyres remain attached to the rim.

Obviously I'm not arguing that a wheel folded in half is better than a tyre coming off the rim - those particular incidents could easily have led to a serious crash. But I am saying that it's quite plausible that there are modes of failure where the tyre staying attached to the rim (even if fully deflated) would allow you to roll safely to a controlled stop, while the tyre blowing off the rim will almost always lead to a sudden and potentially dangerous uncontrolled stop.

But tubular has it's fair share of crash-causing incidents. Didn't Beloki's career ending crash happen from rolling a tub? Pretty sure Armstrong had a crash too. These aren't incidents of slapdash mechanics either, it's just a limitation of that technology. I'd on average hookless is safer than tubular. I've ridden both and I know feel far safer on hookless.

What about hooked tubeless?

choddo wrote:

What about hooked tubeless?

the pinnacle of design IMO, much less likely to get a leak between the tyre and rim

Campag have mini hooked rims for that very reason. Does anyone know what he hit, a rock or a pot hole?  how come no one else hit it, maybe the cause was something else, rim or tyre failure.

Sure, tubulars aren't perfect either. But that doesn't mean we shouldn't still advocate the safest option (based on evidence, rather than feelings). And there's also the option of hooked tubeless in the mix.

Firstly - those Shimano failures are on the rear. It is much easier to balance and stop when your back wheel disintegrates - almost impossible for the front as what the case for De Gendt. Just watch fixie riders tring the longest skid - it's the same skill to control the bike just different circumstances. Had the failures been on the front, I can guarantee those riders would have crashed in the same way De Gendt did. The wheel would jam in the forks and instantly stop turning, regardless of whether the tyre was still attached to the rim or not.

Secondly - a deflating tyre is different from a pretzelled rim. Tyre blowouts are rare and in a latex tubular happen instantaneously too. Any deflated tyre type has the ability to "roll off" the rim (even glued on tubs) and I wouldn't expect an ETRTO approved hookless system to be significantly easier to roll off than a tyre on a hooked rim.

Matthew Acton-Varian wrote:

Firstly - those Shimano failures are on the rear. It is much easier to balance and stop when your back wheel disintegrates - almost impossible for the front as what the case for De Gendt. Just watch fixie riders tring the longest skid - it's the same skill to control the bike just different circumstances. Had the failures been on the front, I can guarantee those riders would have crashed in the same way De Gendt did. The wheel would jam in the forks and instantly stop turning, regardless of whether the tyre was still attached to the rim or not.

I tried to be clear - I agree with this. Those particular failures could have lead to far more serious consequences, and it was blind luck (and excellent bike handling skills) they didn't.

Matthew Acton-Varian wrote:

I wouldn't expect an ETRTO approved hookless system to be significantly easier to roll off than a tyre on a hooked rim.

This is really the nub of the issue. My argument is is that this is not true - that a hookless rim means a tyre is more likely to blow off in the event of damage to the rim (and potentially even with an undamaged rim). And therefore there are some situations where that could be the difference between stopping safely, and a dangerous crash.

It won't make a difference in every situation - yes if your wheel literally folds in half, you're pretty screwed anyway. But I think hookless is still increasing the liklihood of a more serious incident occuring compared to hooked or tubular.