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Broken carbon seatstay: Fondries and Colorado Cyclist come(8 posts)

Broken carbon seatstay: Fondries and Colorado Cyclist comebill
Jun 19, 2003 11:03 AM
through. Colorado Cyclist had been making some uncomfortable noises about whether the damage to my three-week old bike would be covered under warranty, "because we can't figure out how it happened -- what went wrong," but today they said that they'll replace the frame. So, that's good.
More details pleasetoronto-rider
Jun 19, 2003 11:19 AM
What frame, how did it happen, the story....
Brand new Fondriest P4. Carbon with alu lugs. Nice bike.bill
Jun 19, 2003 11:51 AM
Stiff, alert handling, very lively, but pretty danged comfortable. I'd had the bike out maybe a half-dozen times. Once or twice for interval workouts, a couple of very casual noodle rides, and the club's 50-miler twice. At the end of the second club ride, which had included lots of aggressive riding and a couple of good potholes, a couple of guys are standing around checking out the bike, and I'm showing off the sexy curve of the seatstay. I say, "see this line, isn't that cool" tracing my finger down the seatstay, "except that it's cracked." Omigod.
I was sick. I figured that I likely had been riding with it cracked for some time. That this meant that I probably could get it home if I took it easy was some consolation, but I was sick.
The crack was horizontal, about 3/4 of the way up the driveside seatstay. Went about halfway through the tube. you could see that the clear coat on the inside of the stay was cracked as well, although instead of being a sharp line, on the inside there were a few scalloped incomplete cracks. What it looked like was as if some sort of direct pressure had been exerted on the inside of the seatstay, perpindicular to the axis of the seat stay. In other words, pressure from inside out. Imagine if you were to crack a pencil -- the crack opens on the opposite side from where you apply the pressure. Here, the crack had opened on the outside.
Made no sense. Could it have happened in shipping? I don't see how. Not only did it look as if the pressure had come from the inside, but the seatstay actually is concave right there -- it bends in a little. Any stress that you could imagine from shipping would come from outside in, and there just didn't seem to be any way it could have reached that section of the seatstay. Not to mention that I would have seen it. It was a very visible crack. Could my kids have knocked it over or something? Same thing. Not to mention that if it broke by falling over in my living room, who needs that piece of sh*te?
But, all hopefully will be well. They reassured me (somewhat) about the design/build by saying that they not only never had heard of this bike breaking this way, they never had heard of any bike breaking this way. So, I guess it was just a fluke.
Carbon seat stays frighten me!Rich_Racer
Jun 19, 2003 12:18 PM
After that pro (can't remember who) almost died when his seat-stay snapped I just won't go near them. It's been shown that the reduction in both weight and vibration is neglible and to me the increase in risk is too great. Just my opinion, obviously.
and they're getting to be damn near ubiquitous, which givesbill
Jun 19, 2003 12:40 PM
me some confidence that, if there really were a systemic problem other than some flukey stuff, we'd here more about failures. I also was able to ride with it cracked for some (unknown) period of time, so there is some redundancy built in, obviously.
Those worries certainly have crossed my mind, though. I don't think that you're nuts at all.
I think that was a seatpost, not a seat stayterry b
Jun 19, 2003 1:13 PM
are you afraid of carbon seat stays on all-CF bikes or just carbon seat stays on steel/cf, alum/cf and ti/cf bikes?

awful lot of people out there riding Trek 5xxx frames without a flurry of seatstay failures.
Carbon seat stays frighten me!raptorUW
Jun 19, 2003 5:45 PM
i've never heard of a crash like that - anyone care to enlighten me and/or debunk an internet rumor?

i know michele bartoli almost lost a leg due to an encounter with a spinergy - in part prompting last years UCI wheel regs....were you refering to this?
Jun 20, 2003 2:08 AM
It was a triathlete riding a paper-thin 'aero' seatpost. In day-to-day use, the failure rate of CF stays is about the same as any other material. I have 18 000 km on a bike with carbon seat- and chainstays. Hard miles.
After 12 000km I upgraded the rear dropouts to a newer design. Took a day in the factory. Would never have been able to do that with any other material. At the same time watched another frame have the right chainstay replaced after a bad chain-dump gouged big holes in the stay. And that rider rode it like that for 5000km with no problem. And the reduction in vibration and overall improvement in ride quality directly comparing similar frames with and without carbon stays is astounding! That I've experienced. Wouldn't consider any other material, in the same way EVERY bike manufacturer out there is comfortable with carbon forks!!!