Bicycle Mechanics - bike fell and bent gears out of line

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.



PDA
sknhgy
10-24-06, 07:59 PM
First off, I'm not familiar with bike terminology so pardon my descriptions and please, if you answer, use simple wording.
My Trek 820 fell on the right side and bent the "hanging down gear arm" out-of-line with the rest of the drive train. I took it to the bike shop. They said it was a simple fix. I didn't watch what they did but wish I had. I assume they just bent it back.
Has anyone experienced this? I never realized bikes could be so fragile if they get knocked over. Can you tell me what to do next time to fix it? BTW, I am fairly accomplished with tools. I'm just not familiar with the drive train on a bicycle.
Thanks in advance.

Portis
10-24-06, 08:01 PM
http://www.google.com/search?hl=en&q=bent+derailleur+hanger
ryanparrish
10-24-06, 08:12 PM
sheldonbrown.com and parktools.com will help

shoerhino
10-24-06, 08:23 PM
I've had that happen. I bent the rear derailuer hanger back to the veritcal position by eyeballing it. They had space age tools for this procedure today but it worked well enough for me and restore the shifting.

http://www.parktool.com/repair/readhowto.asp?id=39
scuzzo
10-25-06, 07:26 AM
853 or some such tubing right? i had this happen when i went to sprint and the rear wheel Jammed up against the seat stay and seat tube (rear QR malfunction.. CHECK UM FOLKS!)... bent really nasty. took it to the LBS and Jeff.. thanks Jeff. was able to get it right as rain with a der hanger alignment tool... the first bike shop i went to said it was now wall art and i had to toss the frame so. get second opinions if need be.
teiaperigosa
10-25-06, 08:24 AM
I've had that happen. I bent the rear derailuer hanger back to the veritcal position by eyeballing it. They had space age tools for this procedure today but it worked well enough for me and restore the shifting.

http://www.parktool.com/repair/readhowto.asp?id=39

+1 had that happen a long time ago when I knew very little about bike maintenance (when I used to rock a derrailler too)...saw it was bent, I think I hammered it flat
yes
10-25-06, 09:19 AM
If they charge only $10, it is probably worth it, since they have a nice tool to make it really straight. Then, if something else is screwy, you know that it's probably not the der. alignment.
mike
10-25-06, 07:59 PM
Bent derailure hangers are really tricky. Get yourself a book on bicycle repair and monkey around with it. You can often get a bicycle repair book at your local library if you don't want to make the investment.

Anyway, fill your head with mechanical knowledge and have at it. At this point, you don't have anything to lose but time. If time is too valuable and you don't have the time to mess with it, then bring it in to the shop. Derailures are not impossible to do, but it takes time to learn how to get them on and get them adjusted correctly. In addition to the derailure, you have to be comfortable with chain "breaking" to get the chain apart and thread it through the derailure pulleys.

Then you have to know how to tension the cable.... ayaiyai, it might be more complicated than I thought.

So, in a nutshell, it is do-able if you have the time to do it - kinda technical (about a 7.5 on a scale of 10), but a good learning experience and you really don't have anything to lose at this point.