Originally Posted by
Racing Dan
105 is forged. 105 wont crack and break.
105 is
less likely to crack and break. But since it's made of aluminum, it will break if used long enough.
Many examples of broken solid aluminum cranks exist.
Personal anecdote: I remove Shimano cranksets from my new bikes and replace them with
FSA carbon cranks. My cranks currently have about 15,000 miles on them. No issues.