that's reverse bending fatigue - it started at that sharp corner at the outside of the two mirrored fracture halves - not a good design what looks porous is actually where the metal was stretching and absorbing as much energy as possible - the flat stuff is the progressive fracture
On Tuesday, January 20, 2015 at 9:09:15 PM UTC-6, Jim Bronson wrote: > > Porous metallurgy? That looks pretty bad. > On Jan 20, 2015 8:03 PM, "John" <lindbe...@hotmail.com <javascript:>> > wrote: > >> Towards the end of my ride today, I heard a loud crunch and my Ram >> lurched to a stop. Didn't take long to figure out the cause. My Shimano >> Tiagra RD had separated into two pieces. The larger chunk with cable >> attached wrapped around the right chainstay and lodged in my spokes. The >> other piece remained bolted to the dropout. Fortunately, I was going very >> slowly at the time, so no damage was done to my wheel. I wasn't shifting >> at the time, just pedaling along. I was able to break the chain and remove >> the cable so I could at least roll my bike to where my wonderful wife >> rescued me. Surprising because the RD is only a couple of years old and >> has not suffered any tip-overs that might have damaged it. I took a couple >> of pictures of the fracture: >> >> https://www.flickr.com/photos/53546004@N07/16312803255/ >> >> https://www.flickr.com/photos/53546004@N07/16125257318/ >> >> Is it just me, or is this not uncommon? >> >> Off to shop for a new RD. >> >> John >> >> -- >> You received this message because you are subscribed to the Google Groups >> "RBW Owners Bunch" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to rbw-owners-bun...@googlegroups.com <javascript:>. >> To post to this group, send email to rbw-owne...@googlegroups.com >> <javascript:>. >> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
