Originally Posted by
genejockey
I'm not sure that's really indicative of their longevity. They were only ever a very small part of the market, and the C&V crowd tends to be heavily into steel bikes. For example, even though they were introduced in 1986, they're apparently excluded from l'Eroica. So, there may be plenty of completely usable Kestrel bikes out there, sitting in garages. I have seen one in the flesh, out on the road.
And the early carbon bikes (not including the Vitus and Alan carbon bikes) from Trek and the smaller companies seem to have been somewhat overbuilt, given that they didn't weigh all that much less than the aluminum equivalents. Engineers erring on the side of caution is almost always a good thing.
Just did an Advanced Search of Bike Forums for "Kestrel." None of the first 25 or 30 threads were about spontaneous failures---and you know how people like to report those. One mentioned a Kestrel that was locked to a parking meter that was run into by a car traveling at speed. The parking meter was flattened. The Kestrel had a "tiny crack."
The main point of concern among those posts was the difficulty of determining whether a frame was structurally damaged after a crash. That concern is, of course, valid for all carbon frames, not just vintage ones.