RD Exploded
11-07-09, 04:26 PM
#1
gone ride'n
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RD Exploded
My riding buddy and I were out for an afternoon ride - not too long, 20 miles and not too fast, he is running a marathon tomorrow. We were starting up a hill and as he went to change down to the small front ring the chain missed the ring and went off. He kept pedaling to try to get the chain to hop back on before he had to stop. We are not sure what happened next but the chain must have also gotten between the spokes and the large ring on the cassett but in the end it ripped the RD off, sheared the mounting bolt and cracked the RD in the middle. The carbon chorus RD bit the dust and totally came off the bike (dangling like a limp sausage from the chain). I have never seen anything like it before. Seems like there was no other damage. We called the sag van in (his oldest son was at home) - he took the car and I finished the ride solo.
A beautiful day otherwise - but in the mid 40's.
A beautiful day otherwise - but in the mid 40's.
11-07-09, 04:34 PM
#2
Climbing Above It All
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I wonder if the chain didn't get stuck between the frame and the crankset and when it caught the low chainring as he tried to get it back on, pulled tension on the rear der. The der. had to give and it broke.
11-07-09, 09:13 PM
#3
His Brain is Gone!
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Ouch! That's a pricey part!
11-08-09, 02:18 AM
#4
Time for a change.
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Did the same on an XT RD offroad. Didn't explode but it broke in half and snagged the chain into the Spokes. Luckily I had a chain breaker and rode back single speed with an out of true wheel. Think I would have preferred a sag wagon though.
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Spike Milligan
How long was I in the army? Five foot seven.
Spike Milligan
11-08-09, 08:12 AM
#6
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Do you think if he stopped pedaling it would have prevented that? I don't know, just asking.
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George
George
11-08-09, 08:30 AM
#7
gone ride'n
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George,
Maybe, but if the chain was well jamed between the rear spokes and the cassett the wheel rotation would have ripped it out. When we looked at the bike that seemed to be the case.
Maybe, but if the chain was well jamed between the rear spokes and the cassett the wheel rotation would have ripped it out. When we looked at the bike that seemed to be the case.
11-08-09, 11:32 PM
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Used to be a fairly regular occurrence back in the early mountain bike days, and even more frequent with Simplex derailleurs in the '60s and '70s. I must have exploded four or five Simplexes on my old college Peugeot. I forget whether the first Japanese ones that showed up in the LBS were Suntour or Shimano, but the owner sold me one at cost to try out ("It's Japanese--I don't know how they'll hold up"). I used that derailleur from 1970 until I finally donated the bike in the mid-'80s.
11-09-09, 05:18 AM
#9
Pedaled too far.
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I love my "dork disk" the plastic guard that goes between the gears and the wheel. It prevents such tragedies.
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