This past weekend I participated in Levi's Granfondo and had a wonderful time. Amazing roads, people, support and weather for a terrific ride that took me through parts of California that I would otherwise not have ever seen.
One of the sights I thought I'd never see was my beloved Edge Composite 68 carbon clinchers fail under me while riding. These have been a bomb-proof wheel set since day one. 20/24 spokes, WI hub up front, Powertap in the rear with CX-Ray spokes. An absolute dream. My 88kg's have had nothing but great times on these wheels.
I've learned with these wheels that under heaving braking on steep descents you must exhibit caution. You can't ride the brakes and just think you'll be fine when you get to the bottom. I learned this on a very short and steep 20% descent last fall when I had a latex tube blow out. Yes, I was on the brakes the whole way down and should have known better, but thankfully no harm was done to the wheel or myself. Lesson learned, at least I thought...
Some of the descents of the Granfondo were pretty steep and around blind corners. With being unfamiliar with the roads, I made sure I was cautious. Cautious, but also considerate of the fact that I didn't want to overheat the brakes. I didn't experience any problems over the first 60 miles. The rims weren't squealing nor were the rims overheating.
This all changed as I descended down Meyers Grade Road (photo from http://www.steephill.tv's route preview). The day of the 'fondo was just as perfect as this picture.
The descent was made a bit more technical from the 20+mph wind blowing from off the ocean to the right. The signs at the top warn riders that you're about to descend an 18% grade and caution is required. As had been the norm for the descents up until this point, I made sure I descended safely and with the goal of keeping all equipment in tact. To put this is relation to other riders, I was descending just as fast as others with the exception of a former MTB pro who kept bombing past me on descents (I would then pass him on climbs).
Toward the bottom third of this descent I felt a very bad pulsation in the front brake lever. I looked down at the front wheel to see if there was something wrong but there wasn't anything visibly bad. But it was scary to see the fork flexing back and forth under braking; it probably was oscillating at least an inch when I had the front brake applied heavily.
I got to the bottom of the descent and my teammate pulled over a few seconds later to see how I was doing. I spun the front wheel and it got stuck. It wasn't clear to me what happened. I opened the brakes up to let the wheel spin more freely. At this point I saw the issue. Initially it looked like the sidewall of my Rubino Pro had bulged out and was rubbing the break pads (yellow Swiss Stop). But to my surprise it actually was a deformity of the braking area of the rim! I had somehow managed to melt the carbon.
I was able to limp back through the rest of the ride, but took it very slow on corners and was only able to use about 10% of the braking power from the front. When I got home I took the tire off the wheel and noticed the damage was much worse. I thought only one side of the rim had melted. Come to find out it was on both sides. In the picture you'll see how each side of the clincher flares out.
Thankfully I kept the rubber down, but I'll be on the phone with Edge to discuss the details around the failure and what we can do going forward.