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Discussion Starter · #1 ·
HELP...I'm in the midst of a love-HATE relationship with my bike right now. After being off the bike for 3 months I took it out last weekend and discovered some shifting issues.

I have been trying to get the rear derailleur adjusted to no avail. I can't get it to drop into the smallest cog! When I get it running up and down the cassette pretty smoothly it will not go into the smallest. If I LIGHTLY touch it, it will go. I have cleaned my cables. I've adjusted, set, and re-set the limiting screws. I've cleaned and lubed the chain. I've cleaned the derailleur and lubed its pivot points. I've checked the derailleur hanger and it is not bent.

ANY THOUGHTS? The bike, and components, are nearly 10 years old...not sure if that may play into this. All components are Shimano 105s.

Thanks in advance!
 

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I've been down that road as well...I am very sure the limit screw for the small cog (can't remember which screw) is the culprit. Being you have the cable good, just back off the 1 limit screw (CCW) just a bit, maybe 1/8T and then ride. Repeat if necessary. You want to keep the limit as tight as possible, then loosen just until it hits the small cog consistently. Please let us know how it goes. Ride Hard!
 

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If the limit screw is out all the way and the barrel is turned in all the way and it still won't go into the smallest cog, it could be that the cable is too tight. You may have to loosen the RD cable clamp and re-adjust.

Just a guess.

What do you mean you "cleaned all your cables". How many miles are on these cables? Do they feel smooth or rough? Does the bike shift smoothly otherwise, or does it feel sloppy?
 

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I once had a problem like that, I believe on an ultegra RD, that a friend had and corrected me on. On the tension screw, the "washer" has a tang bent on it. Has been a lot of beer under the bridge since then, but I think that the washer tang was supposed to be bent away from the derailer body. I had it installed where it bent toward the body, and was hitting the derailer keeping it from going into the smallest cog.

This may not be your issue at all, and it's been so long since I had the issue, but just brainstorming..
 

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'brifter' is f'ing stupid
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Forget "CLEANING the cables"; REPLACE the cables AND the housing.

Check the cassette lockring for tightness.

If you have a plastic bottom bracket cable guide, replace it.
^This^. The only 'wear' the cables are subject to is them fraying inside the shifter. Unless they fray at the anchor bolt on the derailleur, sometimes the frayed strands will back up into the housing and cause drag. Doesn't sound like your problem.

Whenever you have an issue like this, make sure the derailleur limits are set correctly. Undo the cable anchor and see if the derailleur moves enough to get the chain on both the small and large cogs. Hold the end of the cable in your fingers and actuate the shifter...feel smooth? No? 'Cleaning' the cables does basically nothing because the wear and any contamination will be in the housing. Hence the great advice to replace the cables AND housing. Replacing just the cables will get you exactly nowhere.
 

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^This^. The only 'wear' the cables are subject to is them fraying inside the shifter.
This may be true. However, cheaper galvanized cables can oxidize and get rough even without wear. Roughness causes poor shifting. Just saying. I'm not trying to challenge your expertise, CX. But you deal with racers who ride enough where miles are a much greater issue than time. I've helped more casual riders and seen what happens to cheap cables over time.

It doesn't sound like the cables are his problem though. But I'm pretty sure replacing them with good quality stainless steel cables will improve his shifting otherwise. And replacing the housings can only help too.
 

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I recommended replacing the housing because I've had a similar problem with balky shifting where replacing the cable wasn't enough. I'm guessing the teflon housing liner gets worn from the cable dragging through it. Also, the problem is always on my mountain bike so maybe a little grit sneaks in. Sometimes I got away with replacing only the chainstay housing; other times I had to replace all the sections.

I used to think the housing was a non-wearing item. I've since changed my mind.
 

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Discussion Starter · #10 ·
Thanks for all the replies...been a a busy week or so and just now able to check this post and work on my bike any.

By cleaning my cables I just mean I disconnected it from the derailleur so that I could slide it out of the housing...wipe it down with a clean cloth...and then wipe with a cloth with some lube on it.

This morning I disconnected the cable again, set the limit screw so that the chain was trying to jump off, towards the chainstay. I then brought it back in a bit until it quit jumping/rattling. I then adjust the barrel adjuster just enough so it would move up as I changed gears.

Goes up fine, but again, when I get back down to the 9th cog, it doesn't want to drop into the smallest...until I've been pedaling for a while, then it will.

I cleaned all the pivot points on the derailleur with degreaser and relubed. It's ride-able, but annoying. Can't figure it out. If I loosen the cable any it will not change gears.

Hmmmm...
 

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Ok here is my trouble shooting when it comes to a RD, more so if it is one I have never worked on before.

1 - Check out the RD hanger and make sure it is straight and not bent. This required a RD hanger alignment tool. A bent RD hanger can cause shifting issues.

2- Once the RD hanger is known to be straight then work on the limit screws. Usually once these are set they are good as long as they are set correctly. Unhook the RD cable and then set the high speed screw. Make sure the upper jockey pulley is in line with the teeth on the last cog. Chain should sound very smooth, no audible signs of the chain trying to jump either direction.

3 - Now set the low speed limit screw, use your hand to push the RD up to the top of the cassette. Once again listen to the sounds. I usually allow just a slight over run on this setting so that when you push the shifter into the granny gear that it allows the index in the shifter to fully catch and not drop the chain back down to the next gear. Just a little though, you don't want the RD rubbing the spokes (if you don't have a dork disc installed).

4 - Now turn the barrel adjuster all the way in, then if I don't have any other barrel adjusters in the RD cable system I roll the RD barrel adjuster out about 6 clicks. Now hook the RD cable back up and pull all of the free tension out of the cable by hand and then cinch the RD cable down.

5- Now time to check out the RD trim, try to shift up from the high speed cog and see how clean the shift is, this is where you can really use a quiet room. Once I can get the RD to move up and down clean with no lag on the up or down request I call it done.

Now in that regards, if you hit the shifter to go to the next higher gear and the RD is lazy to drop, screw the RD barrel adj in about 1-2 clicks until it drops clean. If the RD is lazy to up to the lower gear then turn the RD barrel adj out 1-2 clicks until it pulls up clean.

That is about it for me, takes me about 5-10 minutes to reset a RD that I have never messed with before unless it is one that had been damaged in a crash.
 
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