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Derailleur was caught in rear spokes - trying to assess damage
#1
Hello,

My rear wheel from my road bike was stolen a month back, I replaced the wheel but the cassette on the new wheel only had 6 gears instead of 7. I thought I adjusted the guide-screws enough to get by and avoid overshoot but today, in the middle of a long ride, my chain went over the lowest rear gear and my derailleur hanger got caught in the spokes. I wasn't going that fast when it happened (I had just gone over a curb and was starting to accelerate), but there was enough force to break off the bottom jockey wheel and the inner detachable part of the hanger is probably shot. So a decent amount of force, it seems. As it stands, the main part of the derailleur is definitely way out of alignment, perhaps 10 or even 15 degrees, hard to tell exactly. The derailleur's a complicated piece and I'm not a great mechanic, so I can't tell exactly where it bent/broke (or to what extent), thus I'm not sure if it can just be bent back by a good mechanic or whether I've damaged the main derailleur parts.

Anybody have any experience with this? I live in Russia in and don't have a good mechanic I trust here (plus the language barrier), so I'd like an idea of how bad it is before I see anyone. Also, I'm going to Germany in a couple days and could buy a replacement derailleur there, whereas here I might need to order it and it could take a long time to arrive - nobody drives road bikes here.

Also, the dropout on the frame looks okay from what I can tell, but I'm not 100% sure it couldn't have gotten a bit bent as well. I mean, that would mean a LOT of force being transferred through the derailleur, so I think it's very unlikely. Any thoughts on this?
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#2
pictures?

Going over a curb with a road bike ??? !!! ???? If you are going to do that - get a mountain bike.
Nigel
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#3
Have you ever seen a curb on a mountain?
just buy better wheels and never let a curb keep you from point A to B
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
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#4
@Nigel he didn't state how fast he was going. I also need to go over curbs every now and then on the road bike...
Ok. now to the assessment of the damage, difficult with my crystal ball being sent away for polishing at the moment (pictures would help)...

The dérailleur might be shot (very likely). You probably need to get a new one. You also need to check the dérailleur hanger alignment, check the videos on this site, there is one telling you how to do that. If you have a replaceable hanger, get a new one. If you don't: hope for the best...
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#5
I didn't "go over a curb" at high speeds, I just mean that I was making my way onto the sidewalk/bike path, which required that I slow to a crawl in order to jump up the curb without stressing my wheels. I don't think jumping the curb is what did anything - it was almost certainly shifting, though maybe it was the combination somehow.

As to pictures, I took a few and wanted to post them, however my roommate borrowed the cabe I need to upload them; will try to upload them soon.
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#6
I concur with Joe W; your derailleur is most likely shot. I had the same thing happen to me this past spring going about 20 mph. It was so bad that not only was the derailleur bent, but the chain was caught in between the spokes and the cassette. The cage was also mangled beyond repair. Sadly, it was a Dura Ace.

BTW; does anyone know where I can get a replacement cage? I'd hate to just throw it away.
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#7
Your hanger will almost certainly be bent. Derailleur hangers can be bent back into alignment. There are special tools to do it, but if you don't have them, an adjustable spanner, good light and a good eye can do it.

The test to see if it's right is if all the gears work fine across all the range. If it's out, it'll miss gears somewhere in the range.

I'd take the bike to an LBS (assuming they have them in Russia) and get them to straighten it.

DoctorBike
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