Aggiornamento sulla forcella di Hincapie, apparso sulla
rubrica di Leonard Zinn su
Velonews
What about Hincapie's steerer in Paris-Roubaix?Dear Lennard,
George Hincapie's bike had a blasted and black-anodized aluminum steerer tube. Isn't it true that sandblasting lowers the structural integrity of aluminum materials while anodizing only increases surface hardness but not the overall strength of the material? Would a shiny, smooth, heat-treated aluminum steerer tube have been stronger? Was the blasting and anodizing done purely for cosmetic reasons?
Rob
Answer from Trek:
You are correct - Hincapie was riding an aluminum steerer tube in Paris-Roubaix. It was a 6061 aluminum steerer, the same one that we have been using on team and production bikes for over 8 years. Although we are experts in carbon fiber, we have always leaned to the conservative (and, hopefully, safe) side of fork technology. This has prompted us to remain with aluminum steerers, even for our team bikes.
To specifically address the question of your reader, the steerer tube that failed was not sandblasted. George's fork, as well as almost every fork Bontrager makes, was actually shot-peened. The compressive residual stress from peening is what can extend the fatigue life of a part and is the same technique that you'll find on most quality aluminum steerers, handlebars and seatposts. This technique is a well-accepted way of extending the life of an aluminum part. Second, the steerer was anodized to reduce corrosion.
As you may suspect, we have taken the issue of this failure very seriously - not just for the team, but for the safety of the tens of thousands of consumers riding identical equipment. After careful analysis of the broken parts, as well as replicating the failure in our test lab, it was a convergence of issues that combined to cause the failure, with the predominant factors being George's first crash earlier in the day and the brutal nature of Paris-Roubaix itself.
The overriding message that this incident reinforces is that anytime a rider experiences a crash, it is imperative to check the bike over thoroughly before riding on, regardless of the type of bike or the type of fork. Of course George did not have the luxury of time in this instance, but most everyone else does. In fact, this is a good reminder of Bontrager's carbon care policy. Essentially, if you have crashed a Bontrager part such as this Discovery Channel Team Issue fork, we'll sell you a replacement part at a substantially reduced cost - no questions asked. When in doubt, throw it out. Check out the crash replacement program at
www.bontrager.com.
Scott Daubert
Trek Team Liaison