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Tire makers react to Enve warning

Published March 15, 2019

SALEM, Mass. (BRAIN) — Two road tire makers have responded to a safety warning that Enve issued last week about the use of some clinchers on its carbon wheels.

Enve told dealers and registered purchasers of its carbon wheels to avoid certain tires from Vittoria and Challenge. It said it had studied the issue and found that tire models with natural fiber casings and an "open tubular" construction are susceptible to sidewall wear leading to sudden blowouts. In other cases, Enve said, the tires can stretch with use, causing them to come off the rim.

Enve specifically warned against use of the Vittoria Corsa Non-Tubeless tire model, and all Open Tubular Non-Vulcanized Tire models from Challenge. It also said the Specialized S Works 2Bliss 28mm is not compatible with Enve's hookless rims, including Enve's G23 and SES 4.5 AR rims.

Other than the Specialized tire's incompatibility with the hookless rims, Enve's warning applied to all its carbon rims, not specific models. It also indicated that other wheel makers are seeing similar problems with the tires.

"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," Enve said.

Vittoria and Challenge each issued statements about the Enve warning.

Challenge's response could be summed up as "it's not our tires, it's their rim." In particular, Challenge said that Enve's SES model rims have a sharp hook that can cut sidewalls. It said its investigation found the problem can occur with a variety of tires, not just its models.

"Enve's SES have two sharp (<0.2mm) radii in their hooks, that leave two parallel cuts about 0.5mm apart, around the entire radius of our (and other company's) tires, at around 3-4mm above the bead," Challenge said.

Challenge said that because of the hook radius, the SES rim model does not comply with current international standards and said it has notified Enve of the situation. The company is warning consumers to not use Challenge tires on any rims that do not comply with the "2019 ETRTO, past ETRTO or soon to be released ISO 5775 global standards for tire and wheel fit."

On its website, Enve said all its rims comply with ETRTO standards, with the exception of its M Series M60 Plus and SES 4.5 AR Disc rims. The website doesn't say exactly how or why those models don't comply with the standard.

Enve's Jake Pantone told BRAIN on Friday that he couldn't comment on the situation. "We can't comment at this time, but we'll be in touch soon," Pantone said in an email.

Vittoria released a statement this week saying that it has requested specific findings from Enve's investigation. The company noted that it has sold millions of the Open Corsa tires since they were introduced in 1996. "The tire has been run and raced on both steel, aluminum, and carbon fiber wheelsets, including our own, throughout the world with no previously reported consistent failures," the company said.

Vittoria also suggested that riders inspect their wheels for any sharp edges that could cause premature tire wear.

"It makes intuitive sense that any wheels manufactured with sharper than average edges at the bead where that wheel's rim makes contact with our tires may very well see faster deterioration of the tire's sidewall at that point of contact. Such excessively sharp edges can result from design thus affecting an entire model of wheel, from anomalies in the manufacturing process thus affecting a number of wheels manufactured during a production run, or from a failure to observe a manufacturing defect or damage to a single rim.

"We generally see such issues residing with the wheel manufacturer, rather than with our tires. We also believe that to the extent such issues exist, they often pose similar risks regardless of the brand of performance tire used," the company said.

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