Enve wheel blowout

[RDY]

I feel like I'm missing something. How does the air not leak out of where the spokes meet the rim? I'm surprised that the whole cavity can get pressurized.

I am stuck on this also. With all of my carbon rims, the valve stem is significantly smaller in diameter then the the hole from which it emerges. No way sealant is going to make that air tight. Won't any pressure inside the rim just escape through that gap? And even if sealant did manage to find its way to that point, wouldn't there be an obvious mess of sealant around the valve stem/hole?

It doesn't escape ... they both become pressurized. The inner portion of the rim's layup isn't designed to survive pressurization, hence why it's a very bad idea to not have a drain hole. Air leaks or heated and evaporated water ingress can't escape and lead to these failures. It should be an industry standard to have the holes. But, you know ... cycling industry and no regulation.

[apr46]

Its a rates problem, rim doesnt need to be airtight. Air just needs to flow in fast enough to pressurize the rim vs. the rate of exit.

I am generally not pro regululation in the sense i think it often adds cost for very little benefit, but i think the bike industry really needs it.

[mashiehood]

there was a very similar failure of a new 4.5 on another thread.....

[TobinHatesYou]

I am stuck on this also. With all of my carbon rims, the valve stem is significantly smaller in diameter then the the hole from which it emerges. No way sealant is going to make that air tight. Won't any pressure inside the rim just escape through that gap? And even if sealant did manage to find its way to that point, wouldn't there be an obvious mess of sealant around the valve stem/hole?

With all my carbon rims the valve+valve hole is heavily constricted and virtually airtight with just an o-ring smushed on top of it. There’s a reason why ENVE demands the use of the pressure relief nut. Also the Roval Alpinist failure Sagan experienced was after the rim bed ruptured in a curb impact…air escaped into the rim cavity and blew it out. Occasionally you see destroyed Roval rims on the Specialized FB group too where the rim didn’t explode but the walls delaminated so much under pressure that they buckle when the air finally escapes.

I bet the OP or whoever set up the first tire+wheel did have quite a bit of sealant bubble up through the valve hole. This doesn’t just happen with compressors, it’s happening with floor pumps.

I feel like I'm missing something. How does the air not leak out of where the spokes meet the rim? I'm surprised that the whole cavity can get pressurized.

If you’ve ever set up a tubeless wheel you’d know how much air loves to take the path of least resistance. That is either going to be a drainage hole if the rim has one or the valve hole. Spoke holes are virtually air tight in comparison.

[Mr.Gib]

I am stuck on this also. With all of my carbon rims, the valve stem is significantly smaller in diameter then the the hole from which it emerges. No way sealant is going to make that air tight. Won't any pressure inside the rim just escape through that gap? And even if sealant did manage to find its way to that point, wouldn't there be an obvious mess of sealant around the valve stem/hole?

With all my carbon rims the valve+valve hole is heavily constricted and virtually airtight with just an o-ring smushed on top of it. There’s a reason why ENVE demands the use of the pressure relief nut. Also the Roval Alpinist failure Sagan experienced was after the rim bed ruptured in a curb impact…air escaped into the rim cavity and blew it out. Occasionally you see destroyed Roval rims on the Specialized FB group too where the rim didn’t explode but the walls delaminated so much under pressure that they buckle when the air finally escapes.

I bet the OP or whoever set up the first tire+wheel did have quite a bit of sealant bubble up through the valve hole. This doesn’t just happen with compressors, it’s happening with floor pumps.

I feel like I'm missing something. How does the air not leak out of where the spokes meet the rim? I'm surprised that the whole cavity can get pressurized.

If you’ve ever set up a tubeless wheel you’d know how much air loves to take the path of least resistance. That is either going to be a drainage hole if the rim has one or the valve hole. Spoke holes are virtually air tight in comparison.

OK, so if the valve/valve hole is air tight then it would make sense that the rim could blow up. Seems for my rims, the space around my valves stems is easily comparable to any drain holes I have seen - the tend to be pretty tiny.

[RDY]

You mean air escaping from where the valve exits the rim into the open air? How? Do you forgo the compression nut and o-ring? The drain hole is just a hole.

[refthimos]

I am sure Enve will take care of you; they indeed have very good customer service.

This happened to me almost 5 years ago, before Enve released its pressure relief nut, and at the time with Enve only providing a passing reference in an install video noting that you had to use Enve tape when setting up their wheels. My wheel was destroyed and I had to pay Enve $800 for a crash replacement wheel. Going $800 out of pocket didn't feel like very good customer service, but YMMV.

Details here: https://forum.slowtwitch.com/forum/?pos ... 0#p6833610

[tiberiade]

As an update, Enve is replacing the rim free of charge. Appreciated even though it shouldn't have happened in the first place. Still dealing with some pain in my ear.

[Mr.Gib]

You mean air escaping from where the valve exits the rim into the open air? How? Do you forgo the compression nut and o-ring? The drain hole is just a hole.

The compression nut doesn't seem to seal the hole completely. The profile of the nut is of course flat and doesn't match the the curve of the rim. I haven't found the rubber O ring to do much either. I guess some wheels have a more complete seal.

[TobinHatesYou]

https://vimeo.com/328394931

Another example of the telltale signs...and ignoring them. Those creaks/cracks you hear is the carbon delaminating at the edge of the rim. Not noticeable in this video but in-person you should also be able to see the shape of the carbon "fairing" balloon out slightly.

[Mr.Gib]

Great video. Sealant was oozing from multiple spoke holes. I guess the sealant did its job. This whole issue is a strong argument that drain/vent holes should be mandatory. Without them everything could be perfectly fine and then mid-ride the tape leaks a bit and boom - bye bye front wheel, and bye bye your face.

And the comments at the bottom state that after a noise complaint Enve replaced the hubs but not the rims because they decided the noise was nothing to worry about. Not great PR for Enve.

[LedZeppelin007]

The exact same thing happened to me. Did you double wrap the tape tightly?


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[Mr.Gib]

The exact same thing happened to me. Did you double wrap the tape tightly?

Are you addressing the question to me? Not my wheels or my video.

FWIW the only issue I have ever had similar to this was bad tape job that allowed sealant to enter the rim, so yes a breach of the fairing section of the rim. But the tape re-sealed itself because the tire could be inflated without issue and would hold pressure. All that happened was the sealant dried into little bits that I could vacuum out through the spoke access holes. I assume whatever air pressure got into the rim was able to escape somehow - no drain holes.