The ongoing hookless rims saga

[fa63]

Here is a chart to explain why I will be sticking with hooked rims for now

Systems typically have a distribution of demand and capacity within which they operate (in this example, normally distributed). When systems operate at or near their mean (as they often do when everything works as designed), there is adequate safety margin (that is, capacity and demand curves don't overlap). But in the rare cases that the demand (load) ends up several standard deviations away on its right tail of the distribution and capacity (resistance) similarly ends up several standard deviations away on its left tail, the two overlap and you get failure.

Obviously, many people ride hookless rims and tires successfully. It is because their systems are operating at or near their mean. That said, between the low safety margin of hookless rims against tire pressure (and lack of a hook to bail you out when friction alone is no longer sufficient to keep the tire in place), combined with manufacturing tolerance issues with both rims and tires, these rare cases of failure are more likely to occur with hookless systems.

I wonder what the folks who design these things consider an acceptable probability of failure?

[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.

[fourflys]

Originally Posted by benb

Also why the UCI rules don't agree with the ERTO rules.

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 when used as intended within parameters.. some folks have had hookless tires blow off, similar to any other non-tubular tires it seems..

** yep, what Baron just said as I was typing the above..

[Baron Blubba]

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 when used as intended within parameters.. some folks have had hookless tires blow off, similar to any other non-tubular tires it seems..

** yep, what Baron just said as I was typing the above..

Finishing each other's sentences. Gosh, what's next, you want a sip of my coffee or to wipe your nose on my sleeve?

[fa63]

I think it is easy to show with simple math that hooked tires have a greater safety margin compared to hookless. The frustration of many folks (myself included) is that hookless puts a much greater amount of burden on the end user to get everything just right. Even then, things are more likely to go wrong with hookless than hooked rims. And all for what? To save a few bucks and few grams?

Also, I wouldn't be surprised if the UCI does take action, especially since the CPA has now spoken out against hookless. We will see.

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.

[glepore]

I have trouble with the fact that for many years forks came with "lawyer lips" to prevent an unusual occurrence yet the industry wants us to accept hookless rims that have little if any consumer benefit and require diligence in use to prevent a potentially catastrophic event.
And I don't think I'm being dramatic. I had a tubular tire explode while cornering at lowish speed and instantly went down-the same thing would happen with a blowoff while cornering. In a bunch, yeah, it could be ugly.

[Mark McM]

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 when used as intended within parameters.. some folks have had hookless tires blow off, similar to any other non-tubular tires it seems..

You pick a poor barometer to measure against. Time and time again, the UCI has demonstrated both technological incompetence, and lack of regard for rider safety. For the UCI, it is all about money and public perception (and they're only interested in public perception in regard to how it effects the money).

[Mark McM]

Originally Posted by Baron Blubba

I actually just had an experience with a customer yesterday who is building up a Dogma F12. She ordered Princeton Carbon Peak 4550 for it. She received the brand new ones instead of the 'old' model she thought she was getting. She immediately went online to research the differences (aside from the funky profile). She saw that the new ones were hooked, and was worried that the wheels had regressed back to old technology, because the originals were hookless.

So, if I'm hearing this right, Prince Carbon Works used hookless rims on some of their wheels, but has since gone back to hooked rim? Looking at their web site, it appears they currently offer no hookless wheels at all. Have they stated why their wheels re-grew hooks?

[fourflys]

Originally Posted by glepore

And I don't think I'm being dramatic. I had a tubular tire explode while cornering at lowish speed and instantly went down-the same thing would happen with a blowoff while cornering. In a bunch, yeah, it could be ugly.

and no one's went down when a tubed tire blew for whatever reason?

I know I'm sounding like I'm all in for hookless, and really, I don't care that much either way.. I just think folks are making such a big deal.. as far as the CPA, pretty sure they also made a huge stink about disc brakes being dangerous, especially after a rider or two got cut at some race in a crash.. but don't hear anyone having an issue with discs now..

similar to anything on the internet (or media in general), we are always going to hear about the "oh sh*t" moments or "problematic" pieces of equipment based on user experience (I'm to blame here as well at times).. what we hardly ever hear about is folks who have had stellar experiences with stuff.. but in this thread, you have heard from many folks who are actually riding hookless rims who have had zero issues and, yet still, there are folks wringing their hands over it who have NEVER ridden a hookless wheel or, if they did, ever had a problem (at least by the posts).. you all babble on and on about scientific method, etc when it comes to Jan's tire testing, but want to dismiss the results of folks who have actually owned and ridden the product with great success when it comes to hookless.. just a bit hypocritical if you ask me..

[Baron Blubba]

Originally Posted by Mark McM

So, if I'm hearing this right, Prince Carbon Works used hookless rims on some of their wheels, but has since gone back to hooked rim? Looking at their web site, it appears they currently offer no hookless wheels at all. Have they stated why their wheels re-grew hooks?

I just assumed that their product development manager was a Paceline forum member.

[fourflys]

Originally Posted by baron blubba

i just assumed that their product development manager was a paceline forum member.

potd!

[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.

Originally Posted by fourflys

...you all babble on and on about scientific method, etc when it comes to Jan's tire testing, but want to dismiss the results of folks who have actually owned and ridden the product with great success when it comes to hookless.. just a bit hypocritical if you ask me..

[reuben]

The only thing this thread is missing is a Hambini video.

[benb]

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 when used as intended within parameters.. some folks have had hookless tires blow off, similar to any other non-tubular tires it seems..

** yep, what Baron just said as I was typing the above..

I didn't read the UCI rules. I did see a copy of the ERTO standards (linked here I think.)

If you look careful at the stories about the Pro who had the catastrophic blow off in the middle east his mechanic said they were following the UCI rules for wheel/tire combinations.

The ERTO guidelines say that Pros rim + tire combination is not safe. The mechanic was saying the UCI rules said it was OK.

Without reviewing the UCI rules it has to be one of the following:

- The UCI rules are more lenient and/or don't require the same safety margin
- The UCI rules are just rules and are not about safety
- The mechanic is misinformed about the UCI rules?

[glepore]

Originally Posted by fourflys

and no one's went down when a tubed tire blew for whatever reason?

Good grief, I said in the portion of the post you quoted that I myself went down when a tubular exploded. So yes...

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.

I'm a relative weight weenie in recovery but any weight advantage of hookless is laughable.