A Muzi wrote -
Quoted message said:Aluminum cranks break. As do stems and bars. Riders should periodically
inspect for cracks because although the report usually includes the word
'suddenly' the cracks are aften visible for quite awhile before a
catastrophic failure.
After 3 years hard use snapped a LH Shimano Ultegra crank at the foot of a
short steep driveway
when I had just got out of the saddle to try and sprint up the steep rise.
Sheered about 5cm out
from the centre of the crank.
Foot went down on that side, said hello to Mr Pavement and scraped my elbow
but the real pain was a pedestrian looking at
me as a real goose - Not a Good Look Lance.
Anyhow, it impressed my lbs guy and Shimano supplied a new crankset (not
sure why they only supply
both sides as an indivisable supply item?). I had thought a crank was
unlikely ever to fail.
Whilst I had probably ground the pedal on that side once or twice at speed
and probably bumped that pedals into a curb
at least once I would have classified my use as within normal tolerances -
but that was with me at 107kg.
Still haven't broken a stem or a fork and not anxious to do either given
their significance - I think they are the only bike bits I have not broken
over long use.
But Andrew M's right - parts do fail and regular cleaning checking and
replacing anything critical which is suspect on the bike is cheap insurance
best, Andrew