Open tubular failures on ENVE wheels:

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Bigger Gear
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by Bigger Gear

So this was just sent around to ENVE customers today:

Thank you for riding ENVE. We hope that you are thoroughly enjoying your ENVE SES wheelset(s).
Based on reports from the field that tires with cotton, silk, or other natural fiber sidewalls with open tubular style of construction were degrading quicker than expected, we launched a study to understand the validity and prevalence of these claims. As a result of this investigation, we confirmed that tires using natural sidewall materials with an open tubular type construction, are not fit for use with ENVE carbon rims. It is important to note that through this study, we reached out to many dealers as well as other wheel manufacturers to see if their consumers are having the same results as ours. The response was an unequivocal confirmation that these tires were fatiguing prematurely and in some cases resulting in crashes and injury to the rider when the tire sidewall failed or the tire came off the rim without warning.
There are two specific failure modes that have been documented and are not limited to ENVE rims, rather these failures have been consistent in our test lab on a variety of other manufacture’s rims, both alloy and carbon.

The first failure is best defined as a cut or wearing through of the natural fibers on the sidewall of the tire at or near the rim’s hook bead. Once cut through, the tube extrudes through the tear and bursts, often unseating the tire from the rim resulting in sudden loss of control and a crash. The cutting of the sidewall is the result of soft fibers (the cotton or similar textile) being abraded by the harder edge of the rim during the rotational compression cycles of wheel and tire.
The second failure mode is that of the tire itself stretching off the rim. This is can be caused by a variety of factors, among them, low bead stiffness, varying tire diameters, over inflation, or some combo of the three. The tires most susceptible to this failure are those with a “handmade open tubular” type construction. Given the large selection of tires on the market that deliver excellent performance with reliability, it is our recommendation that ENVE customers should not pair these tires with their ENVE wheelsets.

Here are some specific brand/tire models that we DO NOT recommend:
Vittoria Corsa Non-Tubeless (Not ALL Vittoria Tires) – This tire features cotton sidewalls in black, para (tan), and anthracite (gray). This tire has been described to us by Vittoria as a race day only type of tire and that it is not recommended for training or prolonged use. This tire has been the main offender for cut sidewalls. While this one tire is not recommended for use with ENVE wheels, Vittoria’s Rubino model tires and the tubeless ready Corsa Speed have proven safe and reliable in our testing.
Challenge Handmade Clinchers – These are Open Tubular Non-Vulcanized Tires
Models: Criterium SC S, Strada SC S, Paris Roubaix SC S, Strada PRO, Paris Roubaix PRO, Elite PRO
If you have further questions, or a specific tire that you would like to see tested and approved, please contact your ENVE Customer Service Representative at 877-358-2869.


Sincerely,
ENVE Composites


Thoughts? I've used Corsa CX, Corsa G, Open All-Weather, Corsa Control and had no problems on any rim.

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Calnago
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by Calnago

The term “Open Tubular” is nothing more than marketing speak, derived to convince the consumer that the clincher tires they are about to buy (yes, they are simply clinchers) are just like their tubular counterparts except in clincher form. Well, they may be of similar construction, except for one glaring defining fact... they are not tubulars in any way shape or form, they are clinchers. And they will never possess the handling/ride characteristics of their true tubular brethren. As long as they have to be supported by two hard rim sidewalls, and have structural beads to hold them within these sidewalls, they can never truly be expected to behave like a tubular, perfectly round and cradled gently within a rim bed of similar radius, allowing it much more leeway to conform to the contours of the road in all conditions, especially when leaned over in a hard turn. And because it’s cradled and glued to the rim bed, the tires' sidewalls can be made more supple since there is no hard edge they have to butt up against.
It’s the sharp carbon edges of the carbon clincher rims that are the problem, not the tires. If the carbon edges were nice and smooth the propensity to cut the nice supple walls of a high quality (supple), and thus nice riding clincher (marketed as “Open Tubular”) would not be there. ENVE’s warning would like to make you believe it is the tires that are at fault, when in fact what they should be saying is “Please use a really awful riding thick walled clincher made of steel belts if possible, rather than soft and supple silks and cotton, because we’re pretty sure the sharp edges of our carbon clincher rims won’t be able to cut through those”. Exaggerated for effect of course, but not more than ENVE trying to pass the blame to the tires rather than putting it squarely where it belongs... on the sharp carbon edges of the clincher rim bead.
I suspect it’s quite difficult to manufacture a nice super smooth carbon clincher bead, otherwise they would do it. I still recall the clean deep gash in my hand caused by grasping the carbon spokes of a wheel to fix a flat. The edges of the spokes were very sharp. The edges of a carbon clincher bead can be similarly sharp.

@BiggerGear: I suspect if you haven't had a problem, then you probably won't, but that's not to say that another set of rims (same model as yours) might not be blessed with a very sharp section of edge. I have certainly seen carbon clincher rims cut through Veloflex Masters. Veloflex specifically says not to use these tires with carbon rims for this reason. Continental has a similar warning. Yet people will do it, not have a problem, and based on their one success story, state categorically that it's not a problem. I suggest prudence... run your finger around the edge of your carbon rims to check for any sharp edges. If you find some, then run a supple walled clincher at your own risk.
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by Weenie


bm0p700f
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by bm0p700f

Look at the cross section diagrams of enve rims. It's not exactly round. I would not mount any tyre on these. Bead hooks should be round and with a radius of 2mm I think the figure. Many are smaller than this and some like enve's are not round.

That's why tyre cut as they rub against this edge. It not s carbon rim problem but the design of there bead hook.

A few tubeless tyres have failed on there rims too.

Finx
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by Finx

I've purchased and returned two sets of Enve wheels in the last 18 months.

I'll revisit the brand once they come up with a clincher rim design that is compatible with any standard 700c tire on the market.

Until then I'll stick to the brands that already do this.

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kgt
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by kgt

Before riding exclusively tubulars I had been using open tubulars for many years (Vittoria, Veloflex and Challenge) and I had never a sigle issue. Enve's letter is just a warning about Enve rims and not open tubulars IMO.
And IME any open tubular (a high quality, high tpi clinchers that is) rides much better than a 'normal' clincher.

bm0p700f
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by bm0p700f

Image

this is the current Enve 3.4 SES disc

this is what mavic ust looks like. spot the difference in the bead hook (click of the pic to see it in full).
Image

rollinslow
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by rollinslow

kgt wrote: ↑
Thu Mar 07, 2019 9:01 pm
Before riding exclusively tubulars I had been using open tubulars for many years (Vittoria, Veloflex and Challenge) and I had never a sigle issue. Enve's letter is just a warning about Enve rims and not open tubulars IMO.
And IME any open tubular (a high quality, high tpi clinchers that is) rides much better than a 'normal' clincher.

I love Corsa G+ tires, and have them on all my wheel sets including Enve and Corima. This tire has only been around since 2016 btw, and I have been using them since that time. Prior to this I used the Vittora open corsa CXIII. What I respect about Enve is the use of data to support claims, and since I'm a scientist that seems reasonable. The email they sent says "There are two specific failure modes that have been documented and are not limited to ENVE rims, rather these failures have been consistent in our test lab on a variety of other manufacture’s rims, both alloy and carbon". I doubt that they are lying regarding testing.

I'm not sure what about this statement suggests that it's a problems isolated to Enve only when the testing is on rims including other manufacturers. I also did not like the Vittoria response about these being a "race day only tire" when that is not what they market (look at their website). Where is the critical assessement of Vittoria? A reasonable response from Vittoria if our consumer safety was a priority would be that they will conduct or refer their tires for independent testing. Opinion counts for nothing when safety is involved, only data and hopefully Enve will provide more.

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by ToffieBoi

Challenge now have a warning on their website saying "NO ENVE" under their Open Tubular tires.

guyc
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by guyc

Ouch. Enve only?

spdntrxi
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by spdntrxi

guyc wrote: ↑
Mon Mar 11, 2019 3:11 pm
Ouch. Enve only?
their statement says different... but who knows.

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Calnago
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by Calnago

No, it's not just ENVE. A notice like that is basically a CYA (Cover Your Ass) notice to hopefully mitigate their liability when/if somebody's tire tears open and they severely injure themselves in the process. In the USA, product liability is a huge thing, and it seems that "user stupidity" has to be allowed for in the courts, versus using it as an excuse for not making your product completely foolproof. The McDonald's hot coffee on the lap is a good example... or the roofer who's ladder slides out from him after he placed the footings in muddy cow manure or something. Anyway, it's not unknown that the edges on carbon clincher beads (not just ENVE), can be very sharp and like anything sharp against something soft, it can cut through it. We all like to ride as supple tires as possible for sure, and on a tubular rim, no problem. If the sidewall gets cut, it's going to be from something external to the rim itself, like a sharp rock or rough curb or something. It's a risk of riding for sure, but not inherent in the rim itself. Veloflex already warns that their clinchers shouldn't be used on carbon rims. So does Continental. They have had these warnings for years. But ENVE's notice kind of makes it sound like perhaps the tires are at fault. They aren't. Supple tires made with cottons and silks have long been the best riding tires available. They're not going to start adding steel belts so that they can be used with carbon rims which are less than satsifactorily finished on the edges and as such be sharp and/or ragged enough that they can cut through the sidewalls of the nicest riding tires available, those with soft and supple sidewalls.

I think ENVE's notice has brought them more attention that could actually go against them when somebody sues them. They're bascially acknowledging the potential risk by saying that "Hey, these edges are pretty sharp and they could cut through some of these super nice sidewalls of the best tires these days". Hopefully, they will come up with a way to make sure their carbon clincher beads are smoother going forward. But in the courts, I would expect that they might hear... "Well ENVE, people using the best tires available on your rims is something you should easily have been able to foresee, so shame on you for producing rims with sharp edges. Judgment for the Plaintiff... $1Million Dollars!"
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Last edited by Calnago on Mon Mar 11, 2019 4:09 pm, edited 1 time in total.
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guyc
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by guyc

As you know I'm running Turbo Cottons and have thoroughly checked them after 3000 miles on Boras now and can't see anything abnormal. The 28mm's are a slightly beefier version though so maybe that helps.

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Calnago
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by Calnago

@guyc: I’ll bet if you remove those tires and run your fingers along the edges of your Bora clinchers, you’re not going to come away with any blood on your hands. I’ll bet they’re quite smooth although I don’t have any Bora clinchers close by to check that. The Turbo Cottons you mention have probably the most supple sidewalls of any clincher I’ve worked with so far, and I’ve just put a 24mm set on some aluminum Campy Neutron wheels, but the edges of those rim beads are rounded and smooth. Not a problem. There’s a whole bunch of tires that fit into ENVE’s catchall of “Open Tubular”. That term is nothing but a marketing term to describe a clincher in a way that the consumer might think it’s just like a tubular, well... almost... except it’s not. The materials and layers may be similar or the same, but it’s still a clincher.
I would expect the Specialized Turbo Cottons would be cut just as easily or even easier than some of the tires they specifically call out by name. And for sure they should have listed Veloflex, since Veloflex themselves acknowledge the risk of using their tires on carbon rims for this very reason.
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kgt
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by kgt

Calnago wrote: ↑
Mon Mar 11, 2019 4:24 pm
There’s a whole bunch of tires that fit into ENVE’s catchall of “Open Tubular”. That term is nothing but a marketing term to describe a clincher in a way that the consumer might think it’s just like a tubular, well... almost... except it’s not. The materials and layers may be similar or the same, but it’s still a clincher.
So it is not just a marketing thing. Of course open tubulars are clinchers (that's why the "open" before the "tubulars") but in terms of their construction they are made like tubulars. That means that they are not vulcanized, like most clinchers ,but they use hand-glued treads, high tpi treads, they are almost as supple as a tubular etc. IME an open tubular (one from Vittoria, or Veloflex, or Challenge, or Vredestein) feels more like a tubular than a typical clincher (like a Michelin, a Schwalbe or a Continental).

by Weenie


spdntrxi
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by spdntrxi

I've been using TurboCotton in Enve's for......YEARS.. well they are lucky to last a year..on anything but my TT bike. Never had issues

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