The ongoing hookless rims saga

[fourflys]

Originally Posted by fa63

I don't think it is mutually exclusive that many people use hookless successfully and that hookless has a much lower safety margin against tire blow-off. As I said before, hookless is fine when everything works as it should but why take the unnecessary risk? So that Zipp, Enve, etc. can make a few more bucks? And are the consumers aware that there are additional risks? A friend of mine just bought a brand new Giant online (the model he wanted wasn't available at any of the local dealers), and had no idea that hookless rims have much lower tire pressure limits.

safety margins are insanely small at times in manufacturing tolerances.. now you may not be comfortable with a margin, but until we have hookless tires coming off the rim at a verified higher number than hooked, this is just all talk.. I'm not twisting anyone's arm to ride hookless.. on the point about your friend buying a Giant and not being told, I agree it would have been nice for the shop to tell him, but did he receive an owner's manual and did he read it? I don't know for sure if my manual had it in there (because I didn't read it ), but yo can't blame the manufacturer if the buyer doesn't read the manual (assuming it's in there).. or if they don't look on the side of the tire, which I bet says a max pressure of no higher than the recommendation for hookless..

[fourflys]

Originally Posted by glepore

I don't doubt that 95% of the time hookless works. I just don't get how the "potential" problem (not so potential, look at deGent) is offset by some benefit to the user.

same as hooked rims (or tubular in your case).. I'm sure they work 95% of the time as well, except when you had your blowout.. that was my point, any system can fail, but the numbers haven't shown hookless to fail at any higher rate than other systems to this point (unless I missed something).. folks are just wringing their hands at the potential based on what their interpretation of the "safety margin" is..

bottom line is hookless has been out for a while now.. has there been any verifiable data to show that hookless fail at a statistically higher rate than any other system?

[fredd]

Originally Posted by fourflys

same as hooked rims (or tubular in your case).. I'm sure they work 95% of the time as well, except when you had your blowout.. that was my point, any system can fail, but the numbers haven't shown hookless to fail at any higher rate than other systems to this point (unless I missed something).. folks are just wringing their hands at the potential based on what their interpretation of the "safety margin" is..

bottom line is hookless has been out for a while now.. has there been any verifiable data to show that hookless fail at a statistically higher rate than any other system?

Not exactly a quantitative thing, but I've never heard of a hooked tubeless tire simply blowing out of the rim. I've already heard of multiple hookless tubeless ones doing it though. And that's with a majority of tubeless users being on hooked.

[Spdntrxi]

Originally Posted by fredd

Not exactly a quantitative thing, but I've never heard of a hooked tubeless tire simply blowing out of the rim. I've already heard of multiple hookless tubeless ones doing it though. And that's with a majority of tubeless users being on hooked.

The only tire for me and it DID NOT LEAVE the rim altogether, but separated from the bead.

Rim Roval CLX50
Tire : Sworks turbo Cotton 24c
Tube : Latex

It was fairly low speed failure.. tire got stuck in the fork from being flattened.. so stopped pretty quickly, but controllable.

[MikeD]

Originally Posted by fredd

Not exactly a quantitative thing, but I've never heard of a hooked tubeless tire simply blowing out of the rim. I've already heard of multiple hookless tubeless ones doing it though. And that's with a majority of tubeless users being on hooked.

Usually, the only reasons for a tire blowoff using tubes on a hooked rim was a heat related blowoff (rare) or a bonehead move of pinching the tube under the bead. Tubeless on a hooked rim lowered safety factors more and hookless even more than that. I used Vittoria Corsa CX tires (23mm) with tubes that fit real loosely on the rims. I wore those tires out and never had a blowoff at 110psi.

[fa63]

This is true for fields like aerospace where quality control is very strict. In such cases, the distributions of loads and capacities become very narrow because they are so well characterized and verified, and it becomes possible to get away with low factors of safety while remaining safe. I don't think the bike industry should be operating with such low safety margins for obvious reasons, especially on safety critical components like wheels and tires but that is just me.

Hookless tires do indeed come off the rim at lower pressures; it is all simple math. The ISO standard for a blow-off test is the tyre is gradually being inflated to 110 percent of the specified maximum pressure. For hookless, because the rims and/or hookless-compatible tubeless tires are typically rated to 73 psi max, that ends up being roughly 80 psi. For a hooked system, that is 110% of the maximum pressure stated on the tire (not controlled by the rim, because the hook is there to keep the tire in place). For a 28mm Conti GP5000 tire, maximum tire pressure is 115 psi so the limit pressure ends up being 126.5 psi.

Originally Posted by fourflys

safety margins are insanely small at times in manufacturing tolerances.. now you may not be comfortable with a margin, but until we have hookless tires coming off the rim at a verified higher number than hooked, this is just all talk..

[benb]

Originally Posted by fourflys

safety margins are insanely small at times in manufacturing tolerances.. now you may not be comfortable with a margin, but until we have hookless tires coming off the rim at a verified higher number than hooked, this is just all talk.. I'm not twisting anyone's arm to ride hookless.. on the point about your friend buying a Giant and not being told, I agree it would have been nice for the shop to tell him, but did he receive an owner's manual and did he read it? I don't know for sure if my manual had it in there (because I didn't read it ), but yo can't blame the manufacturer if the buyer doesn't read the manual (assuming it's in there).. or if they don't look on the side of the tire, which I bet says a max pressure of no higher than the recommendation for hookless..

Having owned a bunch of Giants I doubt the manual would say this. They have too many bikes and the manuals are generic.

[benb]

Originally Posted by fredd

Not exactly a quantitative thing, but I've never heard of a hooked tubeless tire simply blowing out of the rim. I've already heard of multiple hookless tubeless ones doing it though. And that's with a majority of tubeless users being on hooked.

I had mentioned earlier - Velomax rim + Vredstein tire blew off for me just like these hookless. More than once, luckily always at a stop. Hooked rim with a tube. It wasn't anything like a pinched tube. I've only ever pinched tubes trying to mount Conti's!

[fa63]

Hooked rims can have blow-offs too (some Velomax rims weren't exactly know for their stiffness, either). It would have most likely blown off at a far lower pressure if your rim was hookless.

Originally Posted by benb

I had mentioned earlier - Velomax rim + Vredstein tire blew off for me just like these hookless. More than once, luckily always at a stop. Hooked rim with a tube. It wasn't anything like a pinched tube. I've only ever pinched tubes trying to mount Conti's!

[.RJ]

Originally Posted by fourflys

then why hasn't the UCI banned the use of Hookless? I mean it's not like the UCI to be shy about banning something.. my guess is there isn't enough good data to back up hookless is any more dangerous than hooked [I]when used as intended within parameters..

They didnt waste any time banning angled brake levers without any data on its danger, either.

[merckx]

Originally Posted by Baron Blubba

On a ride today, I was thinking about this thread and all the bad press that hookless gets, and wondered if perhaps the data is one-sided.
Every time anyone has an accident that could perhaps be attributed to their hookless wheel/tire system, a corner of the internet gets incredibly riled up.
But do we hear about similar accidents from people running hooked tires, or good old fashioned tubed tires on good old fashioned rims? Because those systems are not by any means fool-proof either. The difference is, I think, no one is going to point fingers at a 'tried and true' system. Nope, in that case it's clearly user error or just a bazillion to one freak accident and not worth talking about.

I recall there was a recent dust-up on the net regarding Challenge tires separating themselves from the rims they were mounted on. Scared the crap out of me. I had briefly entertained the thought of trying a pair of Strada Biancha tires, but I stepped away from going forward with a purchase.

Hookless rimed-wheels will not find a home in the dropouts of my bicycle for the same reason. What is the point?

[Spdntrxi]

Originally Posted by .RJ

They didnt waste any time banning angled brake levers without any data on its danger, either.

I've seen the hard plastic portion (under the hoods) develop cracks.. from extreme angles so there is that.

[dustyrider]

All this talk of losing a tire reminds me of one of Aaron Gwin’s races. Leogang Maybe not as impressive as his chainless win, but still pretty cool!

[fourflys]

Originally Posted by benb

Having owned a bunch of Giants I doubt the manual would say this. They have too many bikes and the manuals are generic.

so I just looked at my owner's manual.. you are correct, in this very generic manual for Giant bikes, it does not mention hookless tires.. what it does do is tell the owner to go by the information on the tire sidewall as every tire is different (it actually says that).. it also mentions if you aren't sure, ask your dealer your bought the bike from, what the best pressure for you and your bike is.

so, Giant says go by the info on the tire sidewall.. hard to argue with that.. for my Maxxis tires on my Revolt, the pressure range is from 35-60 psi. If I follow the recommendations on the tire, I am well below the margin of safety, even for hooked tires.. now I realize these are 42mm tires, so they would have lower pressures anyway. But if an owner is looking to replace the tires, they can look at the chart I linked earlier (the Giant link on their Hookless wheels), or, as the manual suggests, they can talk to their shop..

[fourflys]

Originally Posted by fa63

Hookless tires do indeed come off the rim at lower pressures;

yep, I agree.. same as a hooked rim/tire combos (as you said earlier in the thread).. no argument there. But I will go back to the fact I have not seen one post where someone on this thread or forum has had a hookless tire blow off.. plenty of folks have "heard about it", but still no bonafide blowoffs that I've seen with all the miles folks ride here..

as I said before, we LOVE to speak of metrics and scientific process on the forum.. "SHOW ME THE NUMBERS!" (in my best Jerry Mcguire imitation)