Silca CEO Josh Poertner hit the headlines last month when he condemned hookless rims for road riding as “a scam”, and he’s now given further justification for his belief, saying that it’s technology he doesn’t like and urging users to be “super-careful”. Josh Poertner is a former technical director at Zipp and chairman of the Bicycle Wheel Technical Committee at the World Federation of Sporting Goods Industries.
> What’s the difference between hooked and hookless bike wheels, and which is better for you?
The safety of road hookless rims has been in the news a few times over the years, most recently as a result of Josh Poertner’s comments on the Marginal Gains podcast last month.
In answering a question of tyre compatibility with hookless Hunt Sub50 Limitless wheels, Josh Poertner said, “There’s no increased aero benefit to hookless rims [as] has been postulated and theorised by brands making hookless rims. It’s just not true. It does not pan out in the real world. We’ve never once seen it to be true in an actual wind tunnel doing actual testing. I hate to say that, but that’s just the truth. In a lot of cases, actually, there’s probably an aero detriment, because it makes the tyre measure a little bit wider than it otherwise would, making it not possible to meet the Rule of 105 in almost all instances.”
The Rule of 105 refers to the principle that a wheel rim should be at least 105% the width of the tyre it’s paired with to have a chance of re-capturing and smoothing airflow.
More than that, though, Josh Poertner said that road hookless rims (as opposed to hookless systems for gravel and mountain bikes) present a safety risk without sufficient margin for error.
> Read our review of the Hunt Sub50 Limitless Aero Disc Wheelset
Having had a month to reflect, has Josh Poertner softened his position? Not much.
“Hookless road: maybe scam was a bit of a strong word [but] I don’t like it,” he says on the latest Silca Velo YouTube video. “I want to see it go away. If you’re on it, be super careful. The ETRTO [European Tyre and Rim Technical Organisation], now they’ve adjusted it after the initial hookless [standard]. I think they were allowing, in some cases, down to a 3mm gap [between the internal rim width and the tyre width]. I think they made it 4mm as the minimum. I personally would not run less than a 5mm gap.”
In other words, a 28mm tyre if you have a 23mm internal rim width.
“If you’re on the 25mm internal, I’d probably be running a 32mm [tyre] on that for hookless,” says Josh Poertner.
Josh Poertner restates that hookless rims do not offer an aero advantage.
“I know everybody says it [hookless] is more aero; it is not more aero. Every time we’ve tested it, it’s not more aero. And one of the reasons it’s not more aero is that the tyre sits out wider in a hookless rim, because there’s no hook keeping it inward. In most cases, you can’t match the Rule of 105 [see above]. You can’t get the tyre narrow enough to allow the rim to really work.
“Companies that make hookless say it’s faster. It’s never faster. They’re super-mad at me for saying that, but it’s just true. We’ve never seen it be as fast because you end up with a tyre that’s almost always too wide for that rim.”
The main points of the video relate to safety concerns, though, Josh Poertner covering issues including the direction of internal tyre pressure, tyre width (stated sizes, which he describes as “essentially nonsense”, versus the measured width on the rims you use), difficulties in establishing true air pressure, and changes in pressure over your ride. He also discusses the “arbitrary 72psi maximum” tyre pressure for hookless systems, regardless of tyre volume.
Rather than have road.cc summarise Josh Poertner’s arguments, it’s best that you watch the video for the full story:
Josh Poertner says, “So would I ride hookless road? No, I won’t. I don’t recommend it. I don’t want to work with teams who have it… I don’t want to be any part of a tyre pressure optimisation or any sort of performance optimisation in those instances, because it is just a bit too risky, and in some cases, it does put us into spots where you’re having to choose a technically incorrect tyre or or less optimal tyre because of the hookless rim, and not because of the day, the race, the course, the pavement, condition, the rider… You’re having to make decisions that are suboptimal.”
Just to be clear, all of this relates to hookless road systems rather than to gravel and mountain bike set-ups where the tyre is much wider than the rim and the tyre pressures are much lower.
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15 thoughts on “Hookless road rims: “Maybe ‘scam’ was a bit strong, but I want it to go away. If you’re on it, be super-careful,” says Silca boss”
PATHETIC STUPID DANGEROUS
PATHETIC STUPID DANGEROUS DESIGN 👌
Utterly irrelevant for 99% of
Utterly irrelevant for 99% of hookless use cases which is consumer cycling.
And I’ve never heard of hookless being more aero – all the marketing suggests its for weight reduction, so he’s proposing an unasked question.
To be fair I’d read loads of
To be fair I’d read loads of times about the supposed aero benefits of hookless. And I’d imagine that most people spending £1-£4k on hookless road wheels are going to want to go fast.
Secret_squirrel wrote:
I’ve seen the aero claim a lot over the years in marketing, and never actually heard of hookless rims being lighter funnily enough. It was supposed to do with the way a hooked tyre would be pinched in more creating more of an undesirably bulb shape. You can even see it on cadex’s page right now for example, https://www.cadex-cycling.com/gb/guide-to-hookless-rim-technology
GCN have a video from 2023,
GCN have a video from 2023, presumably sponsored by Zipp at the time, extoiling the virtues of hookless. Weight and Aero benefits are 2 mentioned. The comments make good reading, I can’t see a single person agreeing with them.
Funny that GCN haven’t mentioned about Josh’s comments on Hookless, especially as he’s a good friend of the channel with Silca being one their main sponsors. Bit of an awkward clash for them with the wheel manufacturer sponsors they have.
The only 2 statements about
The only 2 statements about hookless that I believe are true:
Added to that you are going to have significant compatibility issues.
I can’t see what’s in it for the end user, so it’s a hard pass for me.
Well #3 they’re also supposed
Well #3 they’re also supposed to be more resilient to impacts in MTB. And it makes sense, you’ve got a thicker piece of straight carbon on hookless vs the thinner folded over piece on clincher.
thrawed wrote:
Is that true or do the manufacturers make the whole wall the same thickness as the minimum thickness on a hooked rim because that can already easily take the tyre pressure forces (as hooked rims usually take greater tyre pressure) and would make a lighter rim
MTB Refugee wrote:
What about “They have no hooks”?
I dislike the way tyres
I dislike the way tyres designed for hookless are harder to fit whether you run hookless wheels or not.
ChasP wrote:
Also, doesn’t it counteract the wheel manufacturers claim about less weight on the wheel, because of the lack of the hook, when you have to have a tyre with a thicker, stiffer (presumably heavier?) bead in it?
You use them if you want to,
You use them if you want to, they have nothing useful for me.
Having experienced a hookless
Having experienced a hookless blowout in my kitchen (video on YT) I will never touch them again.
Why buy a wheel that has an important safety element removed?
I had a blowout going around
I had a blowout going around a bend and got badly injured thanks to hookless rims. Never again.
A tyre held on with no hooks
A tyre held on with no hooks is perfectly safe, and 2+2=5.