Joe, Chuck,
my point was, a _properly_ designed steel crank WILL NOT fail, just as a properly designed steel frame will not either. we may not enjoy riding one of these frames, or cranks, so maybe my point is all moot. i've never seen someone try to calculate the size of the stress cycles from pedaling or bouncing on a bicycle over a bumpy road. 'twould be interesting - maybe it's out there on the web ??
there are manufacturing / casting defects in all types of items. I am not talking about failure from casting defects or alloying defects - i'm talking about failure of PERFECTLY manufactured items from stress cycles....
Just because a steel crank fails, even at the pedal eye, doesn't mean it was from stress cycles ... It could have been casting flaws or other manufacturing flaws ... same is true for aluminum, too.
- Don Gillies
San Diego, CA