We've had this discussion before in terms of the risk of riding old aluminum components, including frames. I'm of the "dare devil" school who rides them and doesn't worry much about it. I should qualify this by saying that I do inspect parts frequently, especially those with a reputation for breaking, like Campy cranks and AVA bars and stems. Old parts do definitely fail (of course so do new ones), but a given rider will experience only a few such failures in a lifetime, and in the vast majority of cases a crack will be noticed on a pre-ride or post-ride inspection before any effect is felt. Even when a component cracks during a ride, it usually just causes excessive flex in the part, which calls for riding home at a slower pace which minimizes stress on the cracked component. Usually the very worst that happens is that one has a long walk home. Of course, one hears horror stories of crank arms breaking completely off during a furious sprint, or bars or brakes failing suddenly on a 60 mph descent, but I believe such occurrences are extemely rare. I've never been injured or even come close due to a component other than tires failing. I would say at least 95% of bicycle injuries are caused by careless motorists, unexpected road surface hazards, or the carelessness of the cyclist himself, including failure to have proper lights at night. Of the 5% caused by equipment, nearly all are because of grossly negligent maintenance, like nonfunctioning brakes, or by a tire blowing out at a dangerous moment. The chance of being injured by the failure of a component other than tires is, in my opinion, not much greater than that of being struck by lightning. Other than diligent inspection of parts, I refuse to be worried about.
As to Campy cranks specifically, many develop tiny cracks, some of which you almost need a magnifying glass to see, but this relaively infrequently causes any noticeable effect on performance, let alone the crank breaking entirely apart. Though I prefer French or Zeus equipment, I have had several bikes with Campy NR/SR cranks. The only NR crank I've ever had to replace was on my 1968 Allegro Special, and that crack was not at the spider, or even on the right arm. I noticed on a post-ride inspection that the left crank pedal hole was cracked all the way through, and promply replaced it with no harm done (except to my budget).
Jerry "I don't ride in lightning storms" Moos Houston, TX
> Greeting fellow list members,
> I am looking for a C Record crankset to replace the Super Record version on
> one of my bikes. I just can't seem to put away the fear that it is going to
> break off on me the next time I sprint for the city limit sign or stomp up a
> steep hill. I did file them at the radius where cracks usually occur and
> check them religiously but the doubt persists. Plus I'm getting to that age
> where a 42 just doesn't cut it anymore. So if any of you have such a crank
> in 172.5 and suitable for a daily rider please respond to me off the list.
> Thanks very much,
> Jim Robb
> Granada Hills, CA