(Hookless) What PSI do you run and have you ever blown a tire off?

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spdntrxi
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by spdntrxi

So who's doing the summary for this thread ?

Anyone had a tire blow off ?
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pmprego
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by pmprego

Once upon a time there were one or two occurrences. None with the new generation of wheels and/or tires. It's just like innovation and evolution do make things better. Can we now move on to discuss the meat cutters, also know as disc brakes?

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wheelsONfire
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by wheelsONfire

pmprego wrote:
Thu Sep 22, 2022 7:53 am
Once upon a time there were one or two occurrences. None with the new generation of wheels and/or tires. It's just like innovation and evolution do make things better. Can we now move on to discuss the meat cutters, also know as disc brakes?
:lol: :lol: :lol:
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wheelsONfire
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by wheelsONfire

js wrote:
Thu Sep 15, 2022 7:06 pm
Yes, but on hookless rims rated at 100psi max, when running a 25mm tire.

At 90kg, if I run 60-65psi or less, I can feel the rim bottom out on potholes or rougher sections of road from time to time. Most tire pressure calculators (the one's I'd trust at least) suggest 80psi or more, but I'm quite happy with my numbers. They're well earned and well proven, and I'm not on tires with their own lower limit.
What size of tires do you run?
I am under 70 Kg's and i run higher psi than you do.
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Tracerboy
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by Tracerboy

What people here think from the following assumption ?
Lets take for example Zipp 303FC or 353NSW, rim inner diameter 25mm, hookless desing rim,
Continental tyre GP5000S TR, 30mm (32.3mm when assembled to those Zipp rims, confirmed measure)
rear tyre pressure 3,9 bar/about 56psi
front tyre pressure 3,7 bar/about 54psi
but with inner tube, latex or some mark of TPU tube,

TPU tube and tubeless liquid almost same weight, latex tube little bit heavier.

Is that combination with inner tube even more secured than tubeless system, when something unexpected happens ?

What do you tubeless specialists think about this, any experiences ?

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by Ypuh

Presumably the people who had blow-offs are not there to tell you anymore.
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Maddie
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by Maddie

Same for those with clinchers and tubulars. It can happen to all kinds of tires. If it happens to you, does it really matter if the probability for a tubular to rip off of a rim is lower than a hookless blowout?

jasjas
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by jasjas

js wrote:
Fri Sep 16, 2022 5:35 pm
wheelsONfire wrote:
Fri Sep 16, 2022 1:12 pm
I think it's way less likely on a hooked rim. Personally i would go for a hooked rim.
It handles higher pressure than a non hooked.
That's an accurate statement, but it also highlights different ways to look at this.

One feature that made hookless rims more attractive to me was their added strength. While the hooked rim requires less of the tire bead, the hookless rim is stronger and safer to make - especially from carbon.

I rode and retired a few pair of carbon clinchers before swearing off them. And in three years working as a guide for Rapha's French Randonnees, I only ever saw one set of Carbon Clinchers make it through six days of mountains (while several others were retired, one spectacularly). Removing the braking heat from the rim has obviously made a big difference, but building a hooked rim out of carbon does not play to the material's strengths - you can't keep continuous fibres in tension when you're cutting a bead hook.
why would a hookless rim be stronger? the tire hook isn't machined.

I ve spent several summers in the Pyrenees on Giant (hooked and rim braked) slr0 and 1 wheels with no issues, tubeless is fantastic but hookless just seems to be a solution looking for a problem esp now the industry is disk.

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by pmprego

Almost on the meat cutters :mrgreen: :mrgreen:

js
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by js

wheelsONfire wrote:
Thu Sep 22, 2022 10:04 am
What size of tires do you run?
I am under 70 Kg's and i run higher psi than you do.
I'm normally running 70psi in 25/28 combo (measured as 27/29) on my wheels.
jasjas wrote:
Thu Sep 22, 2022 5:11 pm
why would a hookless rim be stronger? the tire hook isn't machined.
My understanding is that the issue is there's no way to keep carbon in tension around a bead hook, and carbon at its strongest when held in tension. So a hooked bead is either cut or more reliant on the resin, relative to a hookless bead.

jasjas
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by jasjas

js wrote:
Thu Sep 22, 2022 7:18 pm
jasjas wrote:
Thu Sep 22, 2022 5:11 pm
why would a hookless rim be stronger? the tire hook isn't machined.
My understanding is that the issue is there's no way to keep carbon in tension around a bead hook, and carbon at its strongest when held in tension. So a hooked bead is either cut or more reliant on the resin, relative to a hookless bead.
Fair enough, personally, i don't like the idea of my tire being held in place by the tension of the bead and air pressure, regardless of strength difference.

Ypuh
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by Ypuh

jasjas wrote:
Thu Sep 22, 2022 8:14 pm
Fair enough, personally, i don't like the idea of my tire being held in place by the tension of the bead and air pressure, regardless of strength difference.
So you don't drive a car or travel by bus either?

Hookless is just an ordinary cost-cutting manufacturing method with the lucky uptake that it also reduces weight. Selling it as an innovation or improvement is laughable.

Personally I don't like tubeless for road bikes after having used it exclusively for 3 years. Far too much hassle for little to no benefit. Once the honeymoon is over and lots of my riding mates have reached similar conclusions, but please be the one to tell me how great is has been working out for you.



(Big wink, and please don't. Just use whatever you prefer. All systems available work fine for their intended purpose).
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darrydonds
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by darrydonds

js wrote:
Thu Sep 15, 2022 9:51 pm
While a few high-profile rims or tires have come out with the 5 bar limit for pressure lately (Zipp & Conti likely at the top of those lists), there are plenty of options that allow more - likely the majority of offerings, if not of volume sold. So it's not a case of almost all rims/tires limit you to 5 bar.

Even a company as high-profile as Giant allows more pressure than 5 bar and even goes so far to say that if you're using non-Giant/Cadex tires, be sure to use tires that are rated for more than 5 bar. And that's all information specific to hookless rims.
https://www.giant-bicycles.com/global/tire-pressure

With all that said, I can also appreciate that running 25mm tires is nearly a thing of the past at this point. When I'm on 28's, the pressures are lower, but the questions here were about blow-offs, so citing max riding pressures I've used (consistently and safely) seemed the most appropriate to share, and as a bigger rider, my pressures are higher for the same contact patch / road feel as lighter riders.
That's not what Giant says. Here's the text:

"However, should you prefer to run a non-Giant or CADEX tire, listed below are the tires with an indicated maximum pressure above 72.5psi (5 bar) that have passed the Giant test protocol for use with Giant hookless rims. Please note that if the maximum pressure indicated for a tire is 72.5psi (5 bar) or lower and the tire is tubeless and hookless rim compatible as per the tire brand or manufacturer's recommendation, it can be used with Giant hookless WheelSystems and does not have to appear on the chart below [...]"

https://www.giant-bicycles.com/us/hookless-technology

In other words: if tire's max pressure is above 5 bar, it must be on the list approved by Giant; if tire's max pressurer is 5 bar or lower, no need to be on said list.
js wrote:
Thu Sep 15, 2022 9:51 pm
It often takes going to 100psi or slightly over to get the new tires to fully seat on the rim, so I can't imagine how high you'd need to go achieve a blow off. Worth paying attention during that process though - that's an important indicatory of a safe system.
Not sure where this is coming from. It can't be true since many tubeless tires' rated max pressure is below 100psi and many tires can be seated with a normal pump.

jasjas
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by jasjas

Ypuh wrote:
Thu Sep 22, 2022 9:17 pm
jasjas wrote:
Thu Sep 22, 2022 8:14 pm
Fair enough, personally, i don't like the idea of my tire being held in place by the tension of the bead and air pressure, regardless of strength difference.
So you don't drive a car or travel by bus either?

Hookless is just an ordinary cost-cutting manufacturing method with the lucky uptake that it also reduces weight. Selling it as an innovation or improvement is laughable.

Personally I don't like tubeless for road bikes after having used it exclusively for 3 years. Far too much hassle for little to no benefit. Once the honeymoon is over and lots of my riding mates have reached similar conclusions, but please be the one to tell me how great is has been working out for you.


(Big wink, and please don't. Just use whatever you prefer. All systems available work fine for their intended purpose).
Ridiculous comparison, two totally different technologies... can you fit a car tire using 6inch plastic levers? auto wheels have a specific casting to ensure the tire stays on, also subject to tire size ALL tubeless car tyres work on ALL car rims, they also do not require sealant

Not the case with hookless and bicycles, so no they don't work as intended.

I'll tell you how great its been for me and everyone else i know who has used them, just as you are telling me how shite its been for you, user error :)

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wheelsONfire
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by wheelsONfire

As for maximum PSI, there has never been any fact that says you can or should use excessive psi to seat the tire. So 100 psi is dead wrong.
If you can't seat a tire within the rim limits or tire limits, you need to use another method.
Either use a real compressor, or insert an inner tube and seat the tire. Remove the seal at one side, take out the tube and try to seat it again.
Saying you need 100 psi is same as admitting there actually is problem going tubeless.
There's no way around this!
Bikes:

Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)


Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.

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