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.
12 comments:
Wow -- this reinforces my perception that unless you do what Reynolds did and beef up the carbon clincher to substantially heavier than the tubular version, it's simply not up to the task.
Or, you can do what Reynolds then did and use a different design for the carbon clincher rim, the one revealed at Interbike.
I'll stick with my carbon sew-ups for racing, my alloy clinchers for everything else.
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Dear Manley,
Thanks for the report. FYI : I did mention your incident on my blog today and am curious how the conversation with Edge Composites has been going? Will this wheel be replaced in any fashion? :)
Ron, I just posted an update on your site. Edge is taking care of me under warranty.
I had the same failure on my reynolds DV46C rear wheel. Only deformed on one side though.
Wheel was barely 12 months old.
Contacted Reynolds and the response was because I purchased the wheels new from an ebay store there is no warranty. They said any Reynolds item sold through ebay has no warranty. Nice excuse to get out of any warranty claims!
I had the same failure with my Reynolds Attack rims on that road. These were the 2011 version with the newer "blue" brake pads and heat resistant braking surface. I'm now on Kysrium SL's and very happy.
Hmmm... Unknown, can you say what your weight is? I weigh about 141 lb / 64 kg and was thinking about riding my 2011 (new CTg brake track + blue pads) Reynolds Assault carbon clinchers at the Levis' GF this year. I'd appreciate your comments!
When I had the incident on the wheels I was around 200 pounds.
Tubeless carbon clincher wheelset have become increasingly popular in mountain biking. Tubeless tires eliminate pinch flats and allow low tire pressure for better grip on wet, loose, slippery terrain. If the sealant you use stops working for any reason, you can still use a conventional tube to get home.
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Thanks for this write up.
Do we think the tech has improved since 2009 that this wouldn't happen on modern carbon clincher wheel sets?
Great question - I've been thinking of trying out some of the new carbon clinchers. I'm sure on the cycling message boards/forums there are current discussions around what improvements have been made with epoxy tech advancements that work better under high-stress/high-heat situations.
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