It once seemed as if hookless was the future for carbon rims, but there’s recently been a notable change in the tone of the conversation.
Several key figures have spoken out against the technology, while the UCI announced it was launching an investigation into their safety following Thomas De Gendt’s crash at the 2024 UAE Tour.
And at this year’s Tour de France – the sport’s primary shop window – only three of the 23 men’s teams were using hookless rims.
In this third and final instalment of my series on hookless rims (don’t forget to check out parts one and two, on safety and performance), I’m going to attempt to uncover what the future holds for this technology.
What’s the bike industry’s take on the issue? How do professional riders feel? And might cycling’s governing body – the Union Cycliste Internationale (UCI) – have the final word on the matter?
Let’s find out.
Why do hookless rims even exist?
To understand the future of hookless rims, it’s helpful to look back and understand why they even exist in the first place.
According to Jake Pantone, ENVE's vice president of product and brand, the brand introduced the technology to road bike rims to help optimise them for tubeless tyres.
“When we first introduced tubeless,” Pantone says, “we were using soft tooling to create the rim's tyre channel as well as the hooked bead.”
“This allowed for the tooling to be removed from the rim and not be captured by the hooks, but inhibited achieving accurate and precise bead seat diameter dimensions.”
A rim’s bead seat diameter is a measurement of its size where the tyre beads sit. On a 700c or 29in wheel, this is 622mm (with a tolerance of +/- 0.5mm) – hence when a 700x28c tyre has an ISO label of 28-622.
“Having experienced success on the mountain bike side of things, we decided we needed to implement hookless on our road wheels as well," Pantone adds.
“Ultimately, hookless opened the door for optimised bead seat diameters and therefore a more perfect tubeless system.”
For tubeless tyres to retain air, their beads must form an air-tight seal with the rim, whether the rim features bead hooks or not.
As ENVE’s website notes, if the tyre bead isn’t stiff enough to prevent it from stretching, or if the rim’s bead seat diameter isn’t accurate enough, the tyres may ‘burp’ air if it momentarily separates from the rim under load.
Those who’ve been around long enough to have experienced the early days of tubeless will remember that tyres burping air used to be a fairly common issue.
A 2014 column from former BikeRadar US editor, Ben Delaney, documented his “meh-affair with road tubeless”. This included complaints about his tyres burping air during a cyclocross race, for example.
In the same year, ENVE introduced hookless rims to its M-Series MTB wheels, partly in an effort to solve this problem.
As Pantone says, ENVE (and other brands) started porting this tech over to road bike wheels as tubeless was becoming one of the next big things in road cycling, and it appeared as if hookless rims could help solve the same issues.
The trend made headlines when high-profile brands such as Zipp and Giant went all-in on it around 2020 – around the same time as the ETRTO and ISO agreed on a set of standards for hooked and hookless rims for tubeless tyres.
Ahead of the game
A rim is only half of the equation in a tubeless wheel system, though.
If, as ENVE says, the tyre bead isn’t stiff enough to resist stretching, it can burp air or even blow off the rim.
In a blog post in September 2019, ENVE said: “Rim manufacturers have outpaced the rate at which some tyre manufacturers have innovated, creating a complicated environment for consumers when it comes to pairing tyres with their new state-of-the-art hookless road or gravel rims.”
Rather than being deterred by this mismatch, though, brands exploring hookless rims instead pressed ahead with internal testing – creating compatibility guides for existing tyres to help riders make safe choices.
My guess would be that rim manufacturers thought tyre manufacturers would quickly catch up with this technology and the compatibility ‘problem’ would be solved.
When Giant and Zipp rims went hookless, for example, Continental’s flagship tubeless road tyre, the GP5000 TL, was not hookless-compatible, while existing tubeless models from the likes of Pirelli and Vittoria failed Giant’s enhanced internal testing protocol.
All three of those brands (and most others) now produce hookless-compatible road tubeless tyres, but Hunt’s senior development engineer, Patrick Brown, makes it clear that road bike tyres still aren’t all created equally.
He says he’s “never seen a Schwalbe tyre derailment”, but he believes blow-off standards haven’t improved because, “some tyre manufacturers on that ETRTO board are struggling without the hook for tyre retention”.
In fairness to tyre manufacturers, it’s worth remembering how fast things have changed in this area.
As recently as 2019, tubeless tyres were still “a novelty” in the pro peloton, with tubulars being the dominant choice. Fast forward a few years and the opposite is true. Finding a tubular tyre on a WorldTour bike in 2025 is like seeing a Coelacanth in the wild.
Given more time – or a world where brands agree to share or standardise tyre bead technologies – it’s possible we could reach the point where the tyre blow-off standards for hookless rims could be improved.
Do hookless rim and tyre ‘systems’ offer a solution?
In the interim, though, some rim manufacturers moved to producing their own tyres, or producing tyres with partner brands to offer better system performance and reliability.
Zipp, for example, recently collaborated with Goodyear to produce its latest ‘Fitment Series’ tyres, such as the Vector R Z30 NSW and Vector R Z30 SW / 35 SW.
According to Goodyear, these tyres “maximise the overall performance of the tyre and rim as a unified system without some of the traditional constraints” of working independently of specific rims.
The result, Goodyear says, is that “Vector R Z30 NSW is the most efficient tyre Zipp has tested in more than 20 years of wind tunnel testing”, offering “up to 2 watts” improvement in aerodynamic performance (at an unspecified speed) compared to the next best competitor.
Performance benefits aside, Goodyear also says designing tyres to match specific rims helps ensure a correct – and therefore safer – setup.
Giant likewise produces its own Giant- and Cadex-branded tyres, which are rated to far higher inflation pressures than the ETRTO-prescribed limit.
The 25c Giant Gavia Course 1 tyres that came with my 2020 Giant TCR Advanced Pro Disc 2 had a labelled pressure range of 85-125psi / 5.8-6.5 BAR, for example – well in excess of the ETRTO / ISO maximum pressure limit of 72.5psi / 5 BAR.
Giant has updated its guidance on this since, though, lowering the minimum pressure to 70psi / 4.8 BAR for 23 and 25c tyres.
The Giant hookless rims those tyres were mounted to also came with a warning sticker quoting a maximum pressure of 125psi / 8.6 BAR. This was also present on the Cadex wheels that came with Giant’s Propel Advanced SL 0 in 2022.
In any case, Giant’s website says: “Giant WheelSystems are built to be used as a system and Giant and Cadex tyres are always the best choice.”
While this seems an attractive solution to the hookless dilemma from a safety perspective, it’s less so from a performance perspective.
Giant and Cadex tyres, for example, have historically performed poorly in independent rolling resistance tests compared to options from third-party manufacturers.
Goodyear’s tyres are more competitive in this regard, but experience also suggests that when asked to put their money where their mouth is, most roadies at BikeRadar would opt for options from third-party manufacturers, rather than system-specific options.
As a performance-conscious rider, I don’t want to be tied to a specific tyre manufacturer for optimal safety – I want to select the best tyres for my style of riding, no matter which brand produces them.
Josh Poertner, a former chairman of the Bicycle Wheel Technical Committee and an outspoken critic of hookless rims, echoes this sentiment, saying that these systems go “against the mindset of most cyclists who are used to 'upgrading' and swapping parts without a ton of thought… Not to mention obsolescence of things.
“Do we really want wheels that can only work with a specific list of tyres? What happens when new tyres come out, or when the tech moves on and the company stops testing the old rims for the new tyres and so on?”
This aside, recent developments in manufacturing may also have negated the original impetus for hookless rims anyway.
Do three-piece steel mandrels make hookless rims redundant?
As noted in the second part of this series, which explored the claimed performance advantages of hookless rims, Brown says most of the industry is now using “three-piece detachable steel mandrels”.
Although he notes hooked rims remain “slightly more complicated to make”, Brown says these mandrels nevertheless mean it’s now possible to produce precisely sized and shaped rims, while still having bead hooks.
Given the other claimed benefits of hookless rims are vague, and the potential consequences of a tyre dismounting a rim are so dire, this seriously dampens the case for hookless rims.
As a result, Brown said Hunt is “working on the next generation of Limitless rims now”, and internal discussions are taking place about whether to make them hooked or hookless.
Although he noted a final decision was yet to be made, Brown said “you can probably imagine where we're going” and noted Hunt is keen to listen to market feedback on the subject – both from its customers and riders at the highest level of the sport.
What do professional riders think?
Given team sponsors ultimately pay their wages, it’s rare to hear professional riders badmouth kit or technologies.
Occasionally, though – typically when there’s some kind of incident – we do hear from riders or their representatives.
In the aftermath of Thomas De Gendt’s much-discussed crash at the 2024 UAE Tour, Adam Hansen, the president of the professional riders’ union (the CPA), decried the use of hookless rims in pro racing.
Speaking to Velo, Hansen said “the CPA are 100 per cent against hookless rims”, citing concerns around the potential for tyre blow-offs, and how those could cause crashes during races.
Although Vittoria later claimed De Gendt’s crash had been caused by an impact with a rock that broke the rim – and was therefore “unrelated” to the fact his rims were hookless – Hansen doubled down on his views when I spoke to him.
Hansen confirmed he stands by his comments to Velo, and said he hears concerns from riders and teams about the safety of hookless rims “all the time”.
“At least every second week we get a complaint from a rider that a crash happened because a tyre completely came off the rim,” he added.
Hansen also said riders who don’t use hookless rims “are worried about the other riders using them”, because they could get caught up in crashes caused by their use.
The teams currently using hookless rims in the men’s WorldTour peloton are Movistar Team, Team Jayco AlUla and UAE Team Emirates XRG, who use Zipp, Cadex and ENVE wheels, respectively.
In the women’s WorldTour, it’s Canyon//SRAM zondacrypto, Liv AlUla Jayco, Movistar Team and UAE Team ADQ, with the same three wheel brands.
As with Poertner, Hansen said he believes the margin for error with hookless rims is too low, saying the ISO standard for tyre retention being only 110 per cent of the maximum permitted inflation pressure is “crazy”.
Might the UCI ban hookless rims from road racing?
Given the strength of feeling on the issue, I asked Hansen whether the CPA wanted cycling’s governing body, the UCI, to simply ban them.
In response, Hansen was unequivocal. “If it was our choice… Yes, 100 per cent," he said.
“The WFSGI [World Federation of the Sporting Goods Industry] claims they are very safe and we don't share this view.”
ENVE’s Pantone also noted that the return to hooked rims with its latest SES 4.5 Pro wheels, in July of this year, was in part driven by a desire to protect its sponsored professional teams from any potential regulation changes in this area.
The UCI says its technical regulations exist to facilitate “sporting fairness and safety during competition”. It also has a rich history of banning technologies or innovations it views as unsafe.
The UCI banned the use of hydraulic disc brakes in road cycling following a rider injury at Paris-Roubaix in 2016, for example, before re-authorising their use in July 2018.
It also banned the ‘Supertuck’ and ‘puppy paws’ riding positions in 2021, and is set to introduce a raft of regulation changes in 2026 aimed at curbing race speeds.
With hookless rims, though, the UCI has been uncharacteristically restrained on the subject.
Following the De Gendt crash, it issued a statement saying it had directed its SafeR commission to “explore potential improvements and clarifications regarding the use of hookless rims with tubeless tyres”.
According to the UCI , SafeR is an “independent entity dedicated to improving the safety of men's and women's competitions on the UCI International Road Calendar”.
It also committed to carrying out “an in-depth analysis of the appropriateness of the current requirements for the use of different types of equipment in competition, in particular wheels, to ensure that these requirements guarantee the safety of riders”.
18 months have passed since then, however, and we’ve yet to see any results from these investigations.
Given the UCI has recently indicated it will ban certain TT-style aero helmets (such as the POC Procen Air) from mass-start road races, however, it's not unimaginable that it could opt to ban hookless rims from its sanctioned events – potentially leaving riders and teams who own or use them in a pickle.
I contacted the UCI with a number of questions relating to these statements and investigations, but it told me it wasn't able to respond at the time of publishing due to existing commitments such as the Rwanda World Championships. I'll look to cover their take on the situation in another article if I receive a response.
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What do wheel manufacturers think?
Unsurprisingly, different brands have different takes on the subject. Those supporting hookless rims for road use are increasingly in the minority, however.
This represents a stark change, given it had seemed the industry was trending towards a mass adoption of hookless rims.
In support of hooked rims for road cycling
Ralf Eggert, chief road marketing manager for DT Swiss, for example, said the brand has “made a clear commitment to hooked rim technology, prioritising rider safety even if it requires additional manufacturing effort”.
Although Eggert said hookless rims can “work well with wider tyres (over 35mm) and significantly lower pressures (below 5 BAR)” on gravel or mountain bikes, “our aerodynamic testing shows no performance disadvantages with hooked rims – we see measurable benefits.”
On its website, Fulcrum (a subsidiary brand of Campagnolo) states it has stuck with hooked rims for road because it wants to “guarantee the utmost compatibility between our wheels and the tyres available” and because “hooked rims guarantee the maximum level of safety even if the inflation pressure is exceeded.”
Furthermore, it notes “the change in the profile of the tyre is so insignificant that it has no effect on aerodynamics, rolling resistance, reactivity and comfort.”
Reserve, which produces ‘semi-hooked’ rims (more on these shortly), told BikeRadar it believes that “hookless rims present too many limitations in terms of tyre compatibility” and that it is “dedicated to making products that don't require extensive education to use safely.”
Tim Jürgensen, head of engineering at Newmen wheels, noted that the brand originally began making hookless road rims in 2016, long before the ETRTO standardised their design.
These were “validated by an independent German test institute using tyres from the well-known German tyre manufacturers”, Jürgensen says. In 2018, though, Newmen initiated a “voluntary recall” of its hookless road rims “as real-world cases of tyres coming off (primarily with Italian cotton-casing tyres) increased.”
This echoes ENVE’s statement that rim manufacturers “outpaced” tyre manufacturers.
As a result, Jürgensen says “road rims will not go back to hookless for our brand”, although it does support it for gravel and MTB rims.
In support of hookless rims for road cycling
Jeff Schneider, head of product and business development at Cadex, told BikeRadar Giant and Cadex “remain committed to hookless rim technology for both road and gravel applications”.
“Our testing and rider feedback continue to show that, when paired with approved tyres, hookless delivers clear benefits: improved tyre bead security, more consistent tubeless installations, and optimised support for lower inflation pressures that enhance comfort, grip, and rolling efficiency.”
Nevertheless, Schneider said that while Giant / Cadex view the existing international standards as a “solid baseline”, it also acknowledges “that tyre/rim compatibility and inflation pressures remain critical areas where user error can introduce risk”.
Given this, “the standards can and should continue to evolve”, Schneider says, with a focus on things such as clearer labelling and guidance for tyre compatibility and “expanded” safety testing with simulations or real-world use.
Schneider also said Giant / Cadex would like to see a “focus on limiting tyre bead stretch and tightening tolerances to eliminate the issue seen on some tyres. Giant and Cadex add carbon with the Kevlar bead to reduce or eliminate bead stretch.”
Echoing Hunt's contention that “Some tyre manufacturers on that ETRTO board are struggling without the hook for tyre retention”, Schneider told BikeRadar that "tyre bead behavior is one of the key factors in the ongoing standards discussions" and that there is "variation across the industry in how well certain tyres manage bead stretch and retention".
"The challenge", Schneider says, "is that ETRTO and ISO processes are shaped by the same tyre manufacturers who face bead stretch issues, and current standards don’t fully address this broader problem."
"This usually comes down to differences in casing construction, 'proprietary' bead materials, and overall production tolerances."
Schneider contends this issue affects both hooked and hookless rims, though, as a stretched tyre "can fall or blow off any rim" in the event of a sudden puncture.
"From our perspective, this makes standardised testing and more transparent labelling of compatibility essential. Riders need confidence that safe combinations aren’t left to guesswork. Greater alignment on manufacturing tolerances and more rigorous bead-retention testing will ultimately benefit everyone."
He also says both Cadex and Giant rims are made to a stricter bead-seat diameter tolerance of 622mm +/- 0.3mm, instead of the ETRTO / ISO standard of +/- 0.5mm (as noted earlier).
It also selects tyres for safety testing that sit "on the smallest end of that range (-0.3 mm) before being approved for compatibility".
Schneider says "This higher level of precision and testing ensures a more consistent bead fit" and is presumably what enables Giant and Cadex to rate its tubeless tyres and hookless rims to pressures far beyond the current ETRTO / ISO limit.
I also contacted Zipp, but have not received a response to my questions at the time of writing.
What about mini-, micro- or semi-hooked rims?
A notable recent trend has been towards so-called mini or micro-hooked rims.
ENVE’s SES 4.5 Pro wheels, for example, feature "micro-hooks”, while Reserve says its road bike wheels are “semi-hooked”.
Orbea’s new Oquo Road Performance wheelsets feature what it calls a “mini-hook” rim design. Fulcrum also produces road and gravel rims with ‘mini-hooks’.
Reserve’s website states it opted for a “semi-hooked” rim design because: “Full hooked rims… are typically heavier and harder to install tubeless tyres [on]”.
Semi-hooked rims offer, Reserve says, “reasonable limits on tyre pressure (100psi / 6.9 BAR), no tyre incompatibility issues and tyres are easy to install”. Likewise, Oquo says its mini-hooks “improve the tyre-rim interface and reduce turbulence for a faster ride” (although Oquo doesn’t put a figure on how much faster it makes the rims).
They also allow for significantly higher tyre pressures than with hookless rims – up to 95psi / 6.5 BAR for tubeless and 116psi / 8 BAR with inner tubes.
That aside, though, this all sounds great at face value – a rim design that combines some of the potential benefits of hookless rims, with improved tyre-retention capabilities.
As far as I can tell, though, this isn’t a ‘new’ rim standard per se. There is no ETRTO or ISO-defined ‘mini-hooked’ rim.
Instead, Hunt’s Partick Brown says “a rim is ‘tubeless crochet’ if it is more than a 0.5mm hook – so you are complying with the ETRTO ‘hooked standard’ as long as that hook is more than 0.5mm [wide].”
Of the brands mentioned, ENVE is the only one that publishes the size of its ‘micro-hooks’, but Brown’s contention appears to be confirmed by the fact they are exactly 0.5mm wide.
Essentially, it seems these brands have simply come up with a new marketing term for ‘tubeless crochet’.
That’s not to say ‘mini-hooks’ don’t offer any advantages over larger ones, or aren't distinct from how hooked rims used to be made in the past, they just aren’t a new standard.
Brands understandably need creative ways to communicate product improvements to riders, but there’s already an enormous amount of confusion surrounding rim standards and tyre compatibility, and throwing yet more terms into the mix is only likely to make things worse.
Coming full circle
So, do hookless rims have a future in cycling?
Most – but not all – industry experts agree that the case for hookless rims is much clearer for road and gravel bikes.
For road bikes – where tyres remain narrower and pressures relatively high – the tide seems to be turning.
Although there are many happy owners of carbon wheelsets with hookless rims, justifiable scepticism remains about their safety and performance claims.
With the advent of multi-section steel mandrels that enable hooked rims to be made as precisely sized and shaped as hookless rims, the original case for hookless rims also appears to have been significantly undermined.
Especially if, as Hunt and Giant contend, certain tyre manufacturers are struggling to produce tyres with tight enough tolerances and/or beads that can resist stretching sufficiently.
If I had to pick a horse, I’d therefore put my money on ‘mini-hooks’ being the next big thing in road bike rim tech. Arguably, they already are.
The problem with that, though, is that it essentially means we’ve come full circle after a decade or so of rash experimentation, and riders who were early adopters of the tech will be the ones left out of pocket if the industry suddenly abandons it and compatible tyres are no longer produced.
Nevertheless, I don’t believe hookless rims were a big conspiracy to push cheaper-to-manufacture products onto consumers.
Any business would want to make reasonable cost savings if it could, but I also believe brands such as Hunt when they say the difference is “small to negligible”.
Hookless was a proven technology off-road, so I can understand why some brands felt it could be the solution for optimising tubeless wheel systems for road bikes as well.
The mistake, as I see it, was rushing the technology to market before all of the major tyre manufacturers were ready to support it. It is astonishing that hookless rims launched before a brand as significant as Continental had a tubeless road tyre that could be used safely on them, for example.
This issue of tyre compatibility has not only resulted in countless headaches and compromises over the years but, given some of the horror stories I’ve seen or heard about, possibly a few unnecessary accidents, too.
Given this, if you already have a wheelset with hookless rims for your road bike (as I do), then pay close attention to the recommendations for ‘best practice’.
But as BikeRadar’s raison d’etre is “bringing you the best buying and riding advice”, I would advise against buying one until the industry can agree on higher standards and tighter tolerances for both tyres and rims.
