The ongoing hookless rims saga

[fourflys]

Originally Posted by RoosterCogset

This seems to be the rationale that Giant/Cadex implies with their wheelsystem and tires for hookless, while at the same time they have no issues apparently ignoring ETRTO guidelines.

In combination, it's interesting to see what what they're doing. One callout, they're ok with 25mm tires run hookless and indicate a minimum inflation of 70psi.

you kind of forgot to mention the very first note they have..

"Never exceed the maximum (MAX) tire pressure indicated on the rim, the tire or the rim tape."

[fa63]

From today's Strade Bianche race:

[fourflys]

Originally Posted by fa63

From today's Strade Bianche race:

interesting it seems to be the same team again.. I assume Lotto isn't the only team using hookless?

[Mark McM]

Originally Posted by fourflys

interesting it seems to be the same team again.. I assume Lotto isn't the only team using hookless?

And it seems likely that they would be using tires widths of 29mm or wider for Strada Bianche, which would remove the excuse of not complying with ETRTO minimum tire width. Plus they'd probably be using lower pressure than on smooth roads, as well.

[Spdntrxi]

Originally Posted by fourflys

interesting it seems to be the same team again.. I assume Lotto isn't the only team using hookless?

winning team is on hookless..

[fa63]

Originally Posted by Spdntrxi

winning team is on hookless..

Enve have an inner lip built in which should theoretically help with tire retention:



Here is the Zipp rim:

[Mark McM]

Originally Posted by fa63

Enve have an inner lip built in which should theoretically help with tire retention:



Here is the Zipp rim:

Lips on the bead shelf will help retain the tire after it has flatted, but they don't help prevent a blow-off (i.e. the bead lifting over the sidewall). A tire liner is supposed to push outward on the tire at the bead, so it acts similarly to a bead shelf lip. But the tire liner didn't appear to help in either the photo above, or in De Gendt's incident.

[fa63]

What I have been wondering is; are we seeing examples of blow-off with these latest incidents, or is the tire going flat then coming off the rim?

Originally Posted by Mark McM

Lips on the bead shelf will help retain the tire after it has flatted, but they don't help prevent a blow-off (i.e. the bead lifting over the sidewall). A tire liner is supposed to push outward on the tire at the bead, so it acts similarly to a bead shelf lip. But the tire liner didn't appear to help in either the photo above, or in De Gendt's incident.

[MikeD]

It's interesting that those inner lip features aren't required by the ISO/ETRTO standard. Maybe they should be.

[Spdntrxi]

man there is no little bead shelf lip on that Zipp. no thanks

[pakora]

I read through the thread trying to understand a technical bit from the Velo piece that escapes me. I don't know tire science.

Are there variations in pressure in a tire while you're riding? Wouldn't variations in the material structure of the tire mean there are pressure variations standing still even?

Originally Posted by Velo mag

The maximum PSI these hookless tires can have put in them is 73, and if you hit something for sure it goes above the maximum 73 PSI rating on impact. That is why tires are coming off.”

Semi-related, I remember seeing my first hookless mtb rims, maybe the first ever, Rovals, and their claim was (for xc mtb) hookless is better because the manufacturing process for carbon meant angles like you need for a lip are necessarily brittle as the size they are compared to a metal rim.

[pakora]

Originally Posted by fa63

From today's Strade Bianche race:

Probably just the angle but the rim looks impossibly wide for a road rim.

[Spdntrxi]

Originally Posted by pakora

Probably just the angle but the rim looks impossibly wide for a road rim.

353s are 25IW

[pakora]

That's (I believe) wider than my 2012ish XTR wheels and my older Stan's Flows.

I love the brave new road bike world.

[fa63]

Update: A better side shot of that Lotto rider and his bike (on Jered Gruber's Instagram account) shows the Zipp wheel is broken, so there wasn't much for that tire and insert to hold on to...

https://www.instagram.com/p/C4CFFfGL...E5cjFzMnhtOA==