ENVE advising LBSs to not support open tubular tires

[adrien]

Anyone else hear from their LBS on not using open tubular tires on carbon rims? It appears that Enve has seen early failure based on sidewall cuts, and these may be dangerous.

I've been using Open Corsas for years on Enves, with no issues, albeit at relatively high pressures and I change them on the early side. That said, I don't think it's worth the risk. Their message is below:



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

[EDS]

Is there a difference between a clincher tire (non-tubeless) and an open tubular, or just different name for the same thing?

[ultraman6970]

I never seen an open tubular but at least in concept and pictures to me they look exactly the same than any other clincher.

It is interesting what enve says tho...

[harblhat]

Originally Posted by EDS

Is there a difference between a clincher tire (non-tubeless) and an open tubular, or just different name for the same thing?

The manufacturers will tell you that open tubulars are tubulars that haven't been sewn together. Instead they attach clincher beads to the edges. The casing and tread manufacturing techniques are therefore the same, leading to a supposedly more supple tire.

[nicrump]

I've had/get far more fatal sidewall cuts on the last 3 iterations of Michelin PR2-4 than I ever have on my Vittoria opens. In fact I've had zero on my Vittoria's.

[kramnnim]

Originally Posted by EDS

Is there a difference between a clincher tire (non-tubeless) and an open tubular, or just different name for the same thing?

Yes. Open tubulars are like a flat ribbon when not mounted, instead of a molded U shape.

[Spaghetti Legs]

An open tubular is made like a tubular, handmade AFAIK, except where a tublar is closed up to make, well, a tube, and open tubular is not closed and a bead is added. Most regular clinchers are vulcanized, which is some form of industrial press process. A Veloflex tire comes out of the package pancake flat as opposed to a regular clincher which already has a “tire” shape.

The only sidewall failure I’ve ever had was on a Conti GP4000 (no, not trying to start one of those discussions!) and I blew up a pair of Michelin Pro Races when I hit a pothole at 25+ mph.

[FlashUNC]

I applaud them for their public banishment of basically all Challenge tires from their rims.

[kramnnim]

I noticed this on a Veloflex Master I had on an Enve rim. Only a small section of the sidewall was cut at the rim bead/hook. I tend to run tires until the tread is completely worn through in multiple spots.

Zipp rims seem to have a much sharper hook...

[fignon's barber]

I think clinchers inflated to the low pressures that are en vogue , soft sidewalls, and carbon clinchers combined may possibly lead to this. By eliminating one or two of these 3 factors, you're pretty safe.

[Hindmost]

Originally Posted by kramnnim

Yes. Open tubulars are like a flat ribbon when not mounted, instead of a molded U shape.

This would appear to be the key difference. A clincher has its approximate finished shape when it comes out of the mold. The thin casing of an open tubular has to stretch once mounted and inflated to assume the finished shape.

[ravdg316]

Originally Posted by kramnnim

I noticed this on a Veloflex Master I had on an Enve rim. Only a small section of the sidewall was cut at the rim bead/hook. I tend to run tires until the tread is completely worn through in multiple spots.

Zipp rims seem to have a much sharper hook...

Veloflex themselves say not to use their tires on carbon rims.

[benb]

What benefit do these tires actually have anyway?

They definitely separate more money from your wallet but they seem to have the negatives of tubulars & clinchers combined. They've got tubular rolling resistance & repair difficulty. (worse than tubulars?) They've got you on the heavier clincher rims. And maybe they have a good ride?

The main thing I saw people drawn to these years ago was that they often had the highest maximum pressure ratings of anything you could buy that would go on a clincher rim back in the day when there were riders who thought the highest possible pressure was going to make them go faster. The people I knew who had them reserved them for a limited set of racing days as some sort of supposed benefit cause they didn't think they could afford tubulars for A races.

[R3awak3n]

Originally Posted by benb

What benefit do these tires actually have anyway?

They definitely separate more money from your wallet but they seem to have the negatives of tubulars & clinchers combined. They've got tubular rolling resistance & repair difficulty. (worse than tubulars?) They've got you on the heavier clincher rims. And maybe they have a good ride?

The main thing I saw people drawn to these years ago was that they often had the highest maximum pressure ratings of anything you could buy that would go on a clincher rim back in the day when there were riders who thought the highest possible pressure was going to make them go faster. The people I knew who had them reserved them for a limited set of racing days as some sort of supposed benefit cause they didn't think they could afford tubulars for A races.

Challenge I will never buy and same with veloflex so not going to comment on those but vittoria open tubulars are amazing.

The benefit is ride quality. The Corsa G+ is a super nice tire, rides amazing. I also never had a problem with that tire.

[joosttx]

Originally Posted by FlashUNC

I applaud them for their public banishment of basically all Challenge tires from their rims.

B-I-N-G-O. ... I was thinking the same thing