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Old 07-27-05, 04:53 AM   #1
Lord Chambers
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*Sigh*
I guess this started since I re-attached my back wheel after installing a new tube. After putting it on I discovered my highest gears on the cassette were unreachable, so I read up on tuning the drive train, and spent hours playing with the cable tensions until everything was honkey dorrey. But, my drive train is noisy. The gears aren't running smooth, it's like something got shorter or something got longer. The derailleur seems to squeeze the chain then let it out in a burst. Here's a video.

As I say, I don't know why. I don't think my hanger is bent:


Now, the rattling is pretty audible in a quiet garage. While riding the situation doesn't sound so dire, especially the higher the gear I go. I only noticed it today when the wind died and I was going slow enough to notice. I certainly can't feel any vibration in the gearing.

Last edited by Lord Chambers; 07-27-05 at 04:59 AM.
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Old 07-27-05, 05:21 AM   #2
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The tension will affect where the derailleur is, in relation to an index click. As you tighten the tension, the mech moves towards the larger cog. Use the small cable tension adjustment nut, turning it 1/2 rotation and test ride the effect.

The two small screws on the mech set the end stops will set the limits of movement at each end of the range.

parktools.com has full instructions.
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Old 07-27-05, 05:24 AM   #3
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Why are you telling me how to tune the cable tensions? Does that really have something to do with the catching on a single gear as exhibited in the video?
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Old 07-27-05, 06:21 AM   #4
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Quote:
Originally Posted by Lord Chambers
Why are you telling me how to tune the cable tensions? Does that really have something to do with the catching on a single gear as exhibited in the video?
In a word...YES (well I can't watch the video at work but what he said is correct). The shifting works like this: There is a set spacing between the gears in the back. Each click on the shifter is designed to work with that company's derailleur (which is why you can't mix most SRAM with Shimano) to move it a set distance which equals the distance between the cogs. The limit screws set the inside and outside position of the derailleur (set to inner and outter cogs). Then the tension is used to make the fine adjustment of the derailleur. If you add tension to the cable it will make the derailleur move inward. To properly tune it first set the limits of the derailleur and then work on the cable tension. Release all the tension at the shifter (this would be the position with the smallest cog in the back). Now add just enough tension to the cable so there is no slack in the cable. From there check the indexing to the rest of the cogs. If the shifter isn't moving enough then add just a bit more tension. If it moves too much or wont drop back down then remove some tension. Best bet is to read the description on the park tools web site...it really is pretty easy once you get it right in your head.

http://www.parktool.com/repair_help/FAQrindx.shtml
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Old 07-28-05, 07:55 AM   #5
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Just an opinion here....don't work on drive trains with the bike upside down.

I've experiened the same kind of problems on my road bikes. I can't explain why other than possible the chain weight is normaly opposite on the RD and those adjustments are VERY critical.

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Old 07-28-05, 08:05 AM   #6
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Simply removing and installing a rear whell will not affect the derailer or shifting if the wheel is properly reinstaled in the dropouts and you did not gink or bugger anything in the process. Awhile back there was a similar problem.Bike fell over and the RD got ginked.
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