The combination of an unbent derailleur hanger on your frame, the lack of a clearly responsible event like stick in the rear works and the JRA nature of your ride makes the product suspect for the failure.
Ron's astute input and observation of the structural nature of the failed RD's upper body casting compared to several others had me standing in front of my component drawer looking over my little museum of RDs in comparison. None look as though the upper casting was objectified as a place to reduce material mass. My examinations, before needing to refill my coffee cup, support Ron's observation that application of the weight-reducing, material-removing designs of Shimano to their lower end units whose castings are not of the quality of the higher models seems contributory. None of my RDs appear to have taken that casting to task for material reduction. Mostly Suntour, some Shimano and a really nice Mavic 840. Andy Cheatham Pittsburgh On Friday, January 23, 2015 at 4:20:15 PM UTC-5, John wrote: > > Since I didn't see it happen, I have to do my best to understand based on > the after-effects. I was riding in some sticky mud at the time, but there > was no mud on my chain or on the derailer. I took the photo without > cleaning the RD. It's a bit greasy, but no mud or rocks or sticks were > involved as far as I can tell. I was JRA (love that acronym) and it > appears as if the derailer broke in two, flopped around the chainstay still > attached to the cable, and jammed the wheel to a stop. I'll be checking > the wheel for damage, but the derailer hanger is definitely not bent or > damaged. The small half of the derailer was still securely bolted in > place. It's weird, I tell you. Just WEIRD! > > I bought a better Shimano RD at Harris Cyclery during a business trip to > MA this week. I'm hoping it fails in a more graceful manner after a long > life. > > On Thursday, January 22, 2015 at 1:56:10 PM UTC-6, Bill Lindsay wrote: > >> I'm curious about the CAUSE and the EFFECT. Which was it: >> >> A. Did the derailer just separate into two parts on its own? Then the >> broken off part got caught in the spokes, causing you to lurch to a stop? >> >> Cause: Derailer fell apart on its own Effect: Broken bits fell into >> the wheel >> >> B. Did your derailer get caught in the spokes while you were riding? >> Your wheel ripped the derailer in two and you lurched to a stop >> >> Cause: Spokes grabbed derailer Effect: Bike lurched to a stop and the >> wheel broke the derailer >> >> C. Could something else have gotten into your rear wheel, like a stick? >> >> Cause: Stick in the spokes grabbed the derailer. Effect: Bike lurched >> to a stop and the stick broke the derailer >> >> Getting the rear der caught in the spokes is not uncommon. The result is >> usually a busted derailer and often a badly bent derailer tab. Derailers >> randomly commiting suicide by exlpoding themselves into two parts while JRA >> (just riding along) is not common. >> >> On Sunday, January 18, 2015 at 2:56:14 PM UTC-8, John 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
