The amazing exploding derailleur

[BURCH]

I have damaged some parts on mountain bikes before, but never have I seen a derailleur get ripped apart like this.

My wife was running a 10k on Saturday morning and I usually like to bike around the course to follow the run to cheer her on at various spots. Is there a better reason to have a bike? :) Anyhow, I drop my wife off near the start and drive to the finish area because the race didn't end anywhere near the starting area. Park, grab the mtn bike, go about 1/2 a mile, and hop off a curb. As soon as I land, I hear a horrible noise. I stop and look back to find my derailleur in three pieces and sucked into the spokes, chain, and cassette. What a mess. I didn't have a chain tool so I took the pulleys apart to get the derailleur out and took this photo. Unfortunately, without a chain tool I couldn't turn the bike into a single speed and had to put it back in the truck and was only able to see my wife near the finish line. :crap:

I think that the arm of the derrailleur was a little bent and must have swung into the spokes after I hopped off the curb? Not sure really. Funny thing was that I had the bike up on the stand the night before to make sure that it was working ok. It showed no signs of what was to be.

[chuckred]

I sucked a derailleur into the rear spokes at around 40 mph one time. It exploded the derailleur, the wheel, the bike and me...

I'm a little paranoid about rear derailleur set up now...

[jhcakilmer]

I had that happen to an old XT der (8 spd). A piece of wood, perfectly logged itself in between the arm and drop-out, and when the back wheel landed, it snapped off clean. I was about 10 miles from home, without a cell, and it was getting dark.....fun, fun!! ;)

[BumbleBeeDave]

My daughter and I were up at Acadia a few years ago and she was using her SPD pedals for the first time. We stopped at a road crossing, she couldn't get unclipped in time, and toppled over. Bike seemed OK, so we continued across the street and had lunch at Jordan Pond House. When we started up the first hill after lunch, she shifted down and--WHAM! The cage had gotten bent when she fell and when she shifted it far enough over to go up[ the hill it went into the spokes. Wheel was OK, but the derailleur was torn off the hanger, rotated up in the spokes, and the wheel was jammed. Fortunately it was a frame with a replaceable hanger. Maybe your cage got bent somehow while the bike was on the car or before?

BBD

[William]

Were there any Starbucks napkins swirling around the area? ;)
http://forums.thepaceline.net/showthread.php?t=2974&highlight=starbucks+napkin


That sucks. Glad you were fine.



William

[Grant McLean]

I have damaged some parts on mountain bikes before, but never have I seen a derailleur fall apart like this.



"fall apart"?

try jamming your finger into the spokes and see if it "falls apart".
Ok, don't, really,... just sayin' :)

Your derailleur was ripped from the frame by forces great enough
to snap a forged chunk of aluminum ...

-g

[erector]

I had a similar incident occur when cranking up Mathis at AlisoWoods in SoCal. It was an XT 8-sp derailler, that essentially exploded when I was pedaling uphill. I remember not hitting anything, and there was no busted twig to speak of.

For what it's worth, I cleaned the derailler and now use it as a paper-weight on my desk.

[BURCH]

"fall apart"?

try jamming your finger into the spokes and see if it "falls apart".
Ok, don't, really,... just sayin' :)



ha ha, I guess I used the wrong words there, huh? Sorta like the person that takes a wet cell phone back to the store and says it just stopped working.

Poor Derailleur. :D

[BURCH]

For what it's worth, I cleaned the derailler and now use it as a paper-weight on my desk.


Nice Idea. Gotta clean it up.

This was an LX, but I am pretty sure that it was more of a victim than a culprit. I think BBDave may have the issue figured out in that it was laying on its side in the bed of my truck on the way to the run. It could have happened then. Luckily I wasn't 10 miles out or going 40mph. And I didn't see any of those killer napkins floating around.

Maybe the Easter Bunny was bored this week before business openned and took it out on me for bunny hopping off the curb? :rolleyes:

[Grant McLean]

ha ha, I guess I used the wrong words there, huh? Sorta like the person that takes a wet cell phone back to the store and says it just stopped working.



it's best to run it through the dryer first !

:banana:

-g

[slowgoing]

I exploded a rear der about 3 miles into a mtn bike ride in Moab in 105 degree heat. Was able to turn it into a single speed though. Learned a lesson and now I always take more water than I need.

[davids]

I caught a stick and pushed my mtbk's rear derailleur into my spokes a few weeks back. I managed to stop while it was still only bent (although the chain broke), but the noise was startling - I can imagine how much worse your incident sounded - Shearing aluminum can't sound good, atmo!