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"Our systems are proven safe": Zipp joins hookless rim discussion — as photo appears to show Lotto Dstny rider suffer issue at Strade Bianche

Statement comes as Lotto-Dstny rider pictured carrying bike at Strade Bianche, the tyre and foam insert completely detached from his Zipp wheel

Wheel manufacturer Zipp has commented on the discussion surrounding hookless rim technology, specifically its use within professional cycling, and agreed with tyre brand Vittoria that Thomas De Gendt's UAE Tour crash, and the eye-catching images of his tyre left hanging from the wheel with a foam insert falling out, was caused by the Belgian's impact with a rock. The statement comes as a photograph from a second incident, at Strade Bianche on Saturday, suggests that a Lotto-Dstny rider there was left carrying his bike, the front tyre and foam insert both completely detached from his Zipp wheel.

The cause of the Strade Bianche incident remains unclear, neither Lotto Dstny nor Vittoria wishing to comment when road.cc contacted them about the image shared on Instagram by professional photographer Jered Gruber. In the photo (seen below, the ninth image of the post) Johannes Adamietz can be seen carrying his Orbea bike, the front tyre flapping around in the forks and detached from his Zipp wheel. A look at the German's Strava upload from the Italian one-day race, which he failed to finish, reveals a single-word description, "Defektpech", meaning "bad luck" in English.

 Zipp has today released a statement commenting on De Gendt's crash at the UAE Tour last month but has not commented on the Strade Bianche photo, and followed Vittoria in emphasising the strength of impact the veteran breakaway specialist felt when he hit a rock in the road. Last Wednesday, Vittoria said the crash was "unrelated to hookless rim design", Zipp today adding that its "systems are proven safe and continue to be" and that its design team is awaiting delivery of the wheel to "confirm the failure mode and conduct additional analysis" as a matter of "utmost urgency".

The wheel brand also emphasised the "extensive testing" that had been done to ensure safety. The full statement said:

Zipp does extensive testing, both to existing industry ratified standards as well as our own protocols based on over 30 years of designing the fastest wheels on the planet. These tests include both traditional impact tests for the rim as well as retention tests for specific tyre and rim combinations. Specific to tyre retention and hookless rims, our internal protocols subject the tyre/rim combination to pressures well beyond any published standard. This helps ensure safety not only at the maximum stated pressures, but at a margin above.

Zipp worked with other wheel and tyre manufacturers to establish the standards provided by ISO and ETRTO. Zipp wheels that comply with these standards allow tyre manufacturers to certify that their tyres are compatible to be used on our wheels. The certifications from tyre manufacturers inform our tyre compatibility chart. Our systems are proven safe and continue to be.

With respect to the incident involving Thomas De Gendt, Lotto-Dstny team management has confirmed the rider hit an object in the road. Our team is treating the situation with the utmost urgency. It was their assessment that the nature of the impact would have caused severe damage to the tyre and rim regardless of the rim design. Images circulating online indicate damage consistent with a severe frontal impact. As of this moment, our design team in Indianapolis is still awaiting the return of the wheel to confirm the failure mode and conduct additional analysis.

 On Friday, the UCI addressed the discussion surrounding hookless technology, and its safety in racing, stating that it would be looking into the matter as a "matter of urgency" and that the peloton can expect a "rapid decision in the interest of rider safety".

That pledge came at the end of a week when CPA riders' union president Adam Hansen had raised the alarm about potential dangers caused by the use of hookless technology in races.

> Pro cyclists' union "not happy" with hookless wheels after "freak" blowout causes Thomas De Gendt crash – but team defends tyre system as "100% within the rules"

"The CPA is not happy with riders racing on hookless system in the peloton. There have been concerns from riders and teams with this new system," he said. "When you look at the images of Thomas De Gendt's bike, his tyre came off, the safety foam inside got caught in the fork, and that locks up the front wheel.

"This crash is why the CPA are 100 per cent against hookless rims. Tyres should not come off a rim. The maximum psi these hookless tyres can have put in them is 73, and if you hit something for sure it goes above the maximum 73psi rating on impact. That is why tyres are coming off.

"We have heard from some teams that they have put tyres on before, they left them out in the sun and their tyres just pop off. But the manufacturers really like them because it is much easier to produce the rim, you need less moulds for this. The rims are much lighter, it is easier for production, so they are pushing for this."

Hookless rim Fast FWD - 1

> What's the difference between hooked and hookless bike wheels, and which is better for you?

Hansen warned: "One day there will be a mass crash as a result."

Lotto-Dstny's tyre provider Vittoria disputed Hansen's danger claims, instead saying the crash was "unrelated to the hookless rim design" and, in fact, caused by the "impact with [a] rock".

"It is crucial to clarify that the rim's failure resulted from an impact with an object, in this case, a rock, and is unrelated to the hookless rim design. The intensity of the impact caused the rim/wheel to break in a manner that prevented the tyre from staying securely in place. The force was so severe that it tore apart the tyre insert," a Vittoria spokesperson said last week.

"It's important to emphasise that the accident was not a result of any compatibility issues among the components utilised by the team. The Vittoria Corsa PRO 28mm TLR underwent extensive testing on various hookless commercial wheels, including Zipp models (such as 353NSW). The compatibility was thoroughly validated through laboratory tests, outdoor field tests, and races, with official communication provided through the Sram website. As members of ETRTO, we consistently develop our products in strict adherence to ETRTO norms, encompassing both current ETRTO standards and 'Previous Standard Data (PSD)' ETRTO."

Dan joined road.cc in 2020, and spent most of his first year (hopefully) keeping you entertained on the live blog. At the start of 2022 he took on the role of news editor. Before joining road.cc, Dan wrote about various sports, including football and boxing for the Daily Express, and covered the weird and wonderful world of non-league football for The Non-League Paper. Part of the generation inspired by the 2012 Olympics, Dan has been 'enjoying' life on two wheels ever since and spends his weekends making bonk-induced trips to the petrol stations of the south of England.

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8 comments

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Matthew Acton-Varian | 1 month ago
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If Zipp retrieve the wheel in question and can prove their theory then fair enough, that could have happened in any rim/tyre interface. However, it might bring into the spotlight the impact testing requirements for wheels and tyres of any design. Perhaps they need to be more stringent in order to protect riders (pro and recreational) and their equipment from the types of impact that can cause this type of failure.

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wycombewheeler | 1 month ago
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I will say my experience with hookless has been mostly fine, and definitely safe, I have had more instances of air (and sealant) leaking between the tyre and rim, particularly after hitting a pothole hard.

But even on quite damaged rims (to the extent that Zipp oiffered a full replacement free) the tyre never came off in a dangerous way.

Typically running 30mm tyres at 50-60 psi on the road and 47mm tyres at 30-35psi off road.

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Dicklexic | 1 month ago
3 likes

Everyone is acting like we've never seen tyres pulled off the rim before in crashes. It has happened many times with tubulars, and hooked clinchers as well. If you watch the crash in this case, he falls off due to getting cross wheeled, which as we all know has nothing to do with the tyre type. Looks like he then hits something on the grass verge, either a rock as suggested or maybe even the armco barrier. Then when he hits the deck, you can see that his bars turn and he slides with his wheel effectively forced sideways at great speed. This would have the effect of rolling the tyre sideways off the rim in a fashion similar to how you would with your thumbs when removing the tyre intentionally. If the wheel had already hit something with enough force to damage the tyre and lose all pressure then it’s no surprise the tyre rolled off. Similar things happen when tubulars are peeled off the rim, either in a crash like this or when the glue fails due to poor installation, or excessive heat causing it to soften.

I have no personal experience with hookless rims, so can’t comment on how valid the other claims are about tyres just ‘popping off’ without warning, but I think this particular crash, which certainly wasn’t CAUSED by the hookless tyre coming off the rim, has no bearing on hooked versus hookless debate from a safety perspective. After a crash like this he was going to be swapping the bike/wheel regardless, so the end result is the same even if the tyre had remained in place.

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don simon fbpe | 1 month ago
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I'm looking forward to hookless playing a part in the summer tours where temps fuck around with the pressure. Let's see how practical/safe they are then.

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Chris RideFar | 1 month ago
2 likes

As far as I'm aware, the only advantage of hookless rims is that they are easier and cheaper to produce. The fact that various tyre brands state that their tyres and not compatible is enough for me to not want them on my bike.

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Lozcan | 1 month ago
0 likes

Why no lawyer lips.....

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wycombewheeler | 1 month ago
6 likes
Quote:

 Vittoria disputed Hansen's danger claims, instead saying the crash was "unrelated to the hookless rim design" and, in fact, caused by the "impact with [a] rock".

Even if the cause was the crash with the rock, unless a beaded tyre would have gome off a hooked rim in the same impact, then hookless design is related to the incident.

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JEMVisser replied to wycombewheeler | 1 month ago
1 like

That is indeed a valid point there. I still ride hooked rims and inner tubes (my wheel and tire combo is even worse than the pro's) .

I've run narrow road ish tires on gravel, potholes that felt like something should have gone wrong (which it didn't), gone on mtb trails with my cross bike. Those impacts are without a doubt bigger than what de Gendt had.

My question is, what rock should he have hit that was bigger than a full pothole impact on a gravel road or a hit on trails with roots? Because if it were to be because of a rock, my tire would have to explode off the rim according to logic and what happened to me. I carried on riding my 23mm tire fine on gravel as what I've done countless times), he has problems with probably 28mm on smooth tarmack!

Biggest issue: a puncture, but even that is rare for me.

I've also seen tires roll off the rims at cyclocross races, totally not a hookless problem. Cyclocross races are in mud. Mud is way to soft to roll a tire of a bike, especially hooked rims, come on.

Hookless is without a doubt a bigger problem than we think. If I were to race I would ask for anything but hookless, or at least glue my tire on there, sorry, I don't want to crash.

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