In a message dated 9/14/2004 2:08:23 PM PST, gpvb1@comcast.net writes:
Absolutely, don't ride the old Campy cranks. Instead, send them postage
pre-paid to me, and I will see that they are properly recycled. If they are
clean-looking Strada 175s, I may even split the postage with you! ;-)
It has been my experience that some folks experience breakage of these, and
the vast majority of us don't. It doesn't correlate well to rider weight or
power or fitness level, or even to the vintage or age of the cranks to some
extent (although I would say that generally the ones that break are from 1968 to
about 1985, i.e. the "classically" shaped 144 BCD ones - the earlier "boxy" ones
had a beefier cross-section and that seems to be a factor). It does correlate
very strongly to the total mileage on them, as it's a fatigue failure. As
Phil stated, these have some well-known failure modes, but in nearly three
decades of riding them almost exclusively, I've never broken one, nor has my wife,
nor has anyone I've ever ridden with on a regular basis. Recently, I replaced
my wife's SR cranks at about 70,000 miles pre-emptively, more for cosmetic
reasons than concern over any impending failure. It certainly does happen, though,
and somewhat more often with these old cranks than with most other comparable
old cranks of the same period. Check out Damon Rinard's site of crank
failures for pics. of lots of brands of broken crank arms. It's sobering, but it
doesn't stop me from using them.Check for cracks often!
Regards, Greg Parker
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Greg-
It sounds like your experience has been a lot like mine, especially the 1985+
SR/NR models. Even though I think its out of the "CR timeline", that's the
time that Campy got wise about designing in extra material at the
spider-arm/crank arm junction. You probably know them as the non-fluted crankarm design,
but other manufacturers, i.e., Gipiemme were designing in that extra-beefiness
about 4 or 5 years before Campy. In any case, my experience is a lot like
yours, I have never had any cranks break on me, but have seen after 10+ years
riding the same crank, very minor stress cracks did start to form at that critical
junction. I am sure everybody is aware of the most common prophylactic for
this problem is to file smooth the "stress-risers". I have had nothing but good
luck with this method.
Cheers-
Dave Anderson
Cut Bank MT