Mavic responds to wheel collapse article

A photo showing the rim after the accident.

Photo: Photo by Deirdre M. Moynihan, Illustration by Mavic

Editor’s Note: On June 9, VeloNews editor in chief Ben Delaney reported on the failure of a Mavic R-Sys front wheel in a Boulder criterium. The following is Mavic’s response to that article.

MAVIC’S RESPONSE TO VELONEWS ARTICLE PUBLISHED JUNE 9, 2009

This letter is to address Ben Delaney’s article ‘A Shattering Experience’ posted on Velonews.com on June 9, 2009. We thank VeloNews for their continued help in investigating this accident and giving us the opportunity to respond.

The staff at Mavic has long been a fan of VeloNews and their integrity in journalism in coverage of bicycle racing and bike products. However, we feel that Mr. Delaney’s recent coverage and conclusion of his crash at a Boulder criterium on May 17 is premature and does not disclose all the details of the situation.

Mavic has tested the performance of the new R-sys wheel and Tracomp technology through lab testing, field testing and ProTour testing. These tests confirm the performance and safety of the new R-sys front wheel.

Carbon acts differently in a crash situation than steel or aluminum, but all bike components can be pushed to failure with enough force.

Mavic believes that the cause of the accident has not yet been determined. There are several key facts which may indicate that the cause of the accident was not the failure of the Mavic wheel. Those facts and preliminary indications are explained in more detail below.

Initial Inspection of the Bike

The Mavic Engineering Team saw in Boulder:

– That the R-SYS front wheel had ovalized and the spokes had broken
– That the tire had separated from the wheel
– That the valve of the tire tube had been sheared off
– That the bike frame had broken on the main tube

The tire, the tube and the frame were not Mavic products.

The wheel
Fact: There were no significant scratches or dents to the metal alloy inserts on the hub of the wheel, nor to the quick release mechanism which is inserted into the hub.

Preliminary Indication: If the spokes of the wheel had simply failed while the cyclist was riding, then the fork would have dropped straight down with the hub secured in the fork. Under such circumstances, the hub should show evidence of a severe impact, which is not the case here.

The tire
Fact: There is photographic evidence that the tire separated from the rim of the wheel. The tire was a clincher tire.

As support, attached with this letter is a picture taken by a photographer at the scene of the accident. One can see the significant section of the tire which has separated from the rim of the wheel.

Preliminary Indication: A failed tire or a puncture could have caused the cyclist to instantly lose control of the bike, resulting in a crash event involving the subsequent breakage of the wheel. On May 26, the Mavic Engineering Team requested the opportunity to conduct specialized testing on the tire at an independent testing lab in Belgium. As of this date, Mavic has not yet received the tire from Mr. Delaney. Mavic understands that the tire is currently being shipped to Mavic for such independent testing purposes.
The inner tube

Fact: The valve stem is missing. One can see on the picture attached the location of the hole in the rim where the valve stem to the tire should be.

Preliminary Indications: The shearing of the valve stem would occur under conditions where the tire moves, slides or fails, and the wheel rim continues to rotate slightly relative to the tire, cutting the stem. The forces needed to generate such an event would require that the integrity of the wheel (meaning hub connected to the rim by the spokes) had not yet been compromised at the moment the shearing occurred.

The frame
Fact: The frame is made of carbon. The horizontal tube under the chest of the cyclist is broken. The fork (also made of carbon) is not broken and shows no evidence of scratches or impact.

Preliminary Indications: If the horizontal tube broke before the incident, this could have caused the loss of control and the crash event. Also, evidence of impact or damage to the fork would likely be present if the incident was caused by a failure of the spokes.

Summary

Determining the cause of crash and the order in which things failed during the crash is under investigation at the moment.

Mavic takes seriously the rider’s accident in this matter, and the investigation into the causes of this wheel, tire, inner tube or frame failure continues. There are several key facts which may indicate that the cause of the accident was not the failure of the Mavic wheel.