Personally, I'd call Zipp to ensure safety with hookless rims, with that tire. I have ENVE's own tires on my Foundation wheels.

https://sram.zendesk.com/...t-disc-brake-wheels-

Thanks!!!

Brian

---

"We don't inherit the Earth from our ancestors, we borrow it from our children." --Chief Seattle

Careful guys: not all hookless rims are the same unfortunately. Specific rim dimensions such as bead seat diameter or the height of the wing (aka G Height) are more critical to ensure tire retention than the presence of hooks on the rim. If rim brands don't follow the same rules when it comes to those dimensions, then tire retention will vary greatly between one hookless rim and another.

The fact that a certain tire works well with a specific hookless rim does not mean that the same tire will be safe on another hookless rim. In this case, unless Enve delivers a statement that their rims are compliant to the new norm published by ETRTO last year, then I would suggest to stick with tires on their approved list.

i asked this specific question of ENVE, because, ENVE was very early on with hookless. the downside to being an industry leader is that your molds might be done before the industry spec finally comes out. hence my asking ENVE. this is what they said, and i'm patching together a couple of emails in a conversation:

ETRTO specification have changed a bit with the 2020 standard as it relates to tubeless rim geometry and specifically, the drop center. ENVE tends to be on the deeper end of the standard to provide a little more depth for ease of installation. Specifically, the Foundation 45 or 65 are 3.3mm deep. Our tire sits right in the middle of the bead seat diameter standard.

Our original tubeless designs were all based on the 621.5 +-0.5 BSD. We designed those rims to fall within that tolerance and generally had dimensions of 621.35 +-0.2. These would be our SES 3.4 AR and 4.5 AR rims that have a sidewall height of 6.2mm.

The latest version of ETRTO unifies the mountain and road tubeless standard at 621.95 +-0.5. While we have not gone back to retrofit our old rims, our new rims found in our Foundation Collection (45 and 65 Foundation) measure 621.8 +-0.2. These rims have sidewall height of 6.4mm.

---

Dan Empfield
aka Slowman

Dan,

Thanks for the info. What a moving target for the manufacturer. PITA.

FWIW, I've moved the Zipp RT25/28 TL to a set of CLX 40 TL rims using latex inner tubes. Surprisingly to me at least is that the latex (older green michelin) inner tubes have not needed to be topped off for psi in over 4 days. Maybe a combination of a TL tire on a TL rim will help to seal the latex slow leaks better?

Brian

---

"We don't inherit the Earth from our ancestors, we borrow it from our children." --Chief Seattle

very interesting topic and i appreciate your thoughts in the HP article a lot as well.
what remains to be discussed and is so far unproven afaik are the failsafe properties. this is less an issue in long distance, as you can take your time to fix a flat (even though the narrative is "self-healing" when installed properly, flats happen) and as long as there are no steep and fast downhills what is discussed so far should be "safe" enough. but in short course (as well as road racing), the tire should not hop off your rim at the cost of destroying the wheel even as you continue to ride it hard to get to T2.
how does the industry rate the failsafe properties of the newest gen TL compared to tubulars, which is the last reason to consider such ancient tech?