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Old 05-04-08, 02:13 PM   #1
IronMac
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Chain Is All Over the Place!

Hi all,

Having a lot of difficulties here. I changed my chain (Shimano IG for a 7-speed Deore DX system) about a month ago and everything seemed fine. There might have been a skip or two but nothing that I thought I would worry about.

I'm currently taking a bike repair course and the instructor said that my rear shifters were really "stiff" so he adjusted something (sorry, can't remember what) and on the ride home the chain was starting to skip. On a ride later on in the week, it seemed to downshift in the rear to the next higher cog/wheel or would try to but it would also seem to skip in place and at times it would upshift too. It seems to just randomly do this whether I am just pedaling along or pushing hard.

So, the instructor had another look at it and suggested to oil/lube the cable guide around the rear derailleur which I did (used Tenacious Oil) and took it out for a spin. What a disaster! It's all over the place.

I had a look at Sheldon Brown's site and one solution was to lube the cable guide. Now, I don't know what else to do...class is tomorrow night by the way.

Any suggestions appreciated. Thanks!
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Old 05-04-08, 02:20 PM   #2
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You could start by eliminating the cable/housing as an issue. Less than $5 in parts and you'd get rid of any inherent friction or routing issues.

Other things to check for:

-Hanger alignment
-Worn cogs
-Cable adjustment
-Lube derailleur pivots
-Check for worn shifter
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Old 05-04-08, 02:40 PM   #3
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Quote:
Originally Posted by IronMac View Post
Hi all,

Having a lot of difficulties here. I changed my chain (Shimano IG for a 7-speed Deore DX system) about a month ago and everything seemed fine. There might have been a skip or two but nothing that I thought I would worry about.

I'm currently taking a bike repair course and the instructor said that my rear shifters were really "stiff" so he adjusted something (sorry, can't remember what) and on the ride home the chain was starting to skip. On a ride later on in the week, it seemed to downshift in the rear to the next higher cog/wheel or would try to but it would also seem to skip in place and at times it would upshift too. It seems to just randomly do this whether I am just pedaling along or pushing hard.

So, the instructor had another look at it and suggested to oil/lube the cable guide around the rear derailleur which I did (used Tenacious Oil) and took it out for a spin. What a disaster! It's all over the place.

I had a look at Sheldon Brown's site and one solution was to lube the cable guide. Now, I don't know what else to do...class is tomorrow night by the way.

Any suggestions appreciated. Thanks!
If he didn't spend more than a minute doing this "fix" he may have just messed with the cable tension. Otherwise to fix a "stiff r.d" He may have inadvertently bent the r.d itself, the hanger, or kinked housing/cable while working it back and forth after spraying it with WD40 etc.

The latter situation signifies gross incompetence. If your drivetrain was skipping prior to this (like you said) then your drivetrain is shot anyways.
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Old 05-04-08, 05:18 PM   #4
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Great, it sounds like it could be anything!
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Old 05-05-08, 04:20 AM   #5
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What kind of shifters do you have? Are they indexed or friction shifters? The thing he shifted, where was it? Was it part of the derailer or the shifter?

You could look at Park Tool's website on derailer adjustment. I would just start from the beginning and do the adjustment.
http://www.parktool.com/repair/readhowto.asp?id=64
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Old 05-05-08, 05:48 AM   #6
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Thanks everyone for the feedback. Sweetlou, they're Rapidfire shifters (index) and I think he adjusted the tensioner on the shifter.

Anyways, I sat down with a bike repair book (Bicycling Mag's) and adjusted the cable tension knobbie on the rear derailleur. From the very start, there was a problem because the chain was half on and half off of the prior larger cog as I shifted. Turning by quarter turns anti-clockwise I adjusted it until the chain firmly sat on the cog every time I switched gears. Went through all of them and then I took it out for a spin. Works fine for the couple of blocks' ride.
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Old 05-05-08, 12:20 PM   #7
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Great to hear. Good luck in your repair course.
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Old 05-06-08, 03:42 AM   #8
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Thanks...course is coming along nicely and last night's ride had not one complaint from the drivetrain.
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