Chris Ioakimedes wrote:
> I was asked by a local mechanic about filing Shimano and Campy cranks.
> He was told that by filing a nice radius where the crank meets the
> spider, that they would not crack. Does anyone have any experience with
> chris ioakimedes
> Fairfax Califormnia
It was fairly common knowledge and a fairly commonly done thing in Southern California to file the web at the junction of the arm and the spider in the mid 1970s and maybe/probably before. I don't know if this was commonly done else where, but I heard that it was a common enough practice among race mechanics in Europe.
Campagnolo Record cranks routinely develop a small crack at the web with heavy use because the metal comes to a very thin, knife-like edge. If a crack is found there it can be file out and polished to keep it from propagating or you can file the crank before it develops this crack to keep a crack from forming.
I have seen Campagnolo cranks crack and break at the pedal eye and in the middle of the arm where "COLNAGO" was pantographed in the flute, but I have never seen one break at the crank and spider junction. I sure it has probably happened though, since all parts, steel or aluminum, will break with enough abuse.
I'm not aware of anyone filing Shimano cranks.
Broken Bicycle Cranks site:
Chuck Schmidt South Pasadena, Southern California