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Discussion Starter · #1 ·
Relatively new (less than 200 miles) Shimano 105 RD. and Ultegra 12-27 cassette. Seems to be a new problem that the chain will not upshift. I put the bike on the stand and checked for a cable obstruction that would prevent the cable from releasing but couldn't find any. Started messing around with the indexing and started over. I turned the barrel completely clockwise and started turning counter-clockwise until the chain would down shift 1 cog. Turned counter clockwise until the chain started to rattle and backed off a 1/4 turn. Checked all the gears from this point. The chain downshifts perfectly, but will not upshift. If I release the paddle (the STI lever) 3-4 times, the chain will drop 3-4 cogs all at once, but never one at a time.

Should the next step be replacing the cable? Is it safe to assume there is an obstruction in the housing somewhere or is there something else that I should be checking?

Thanks for the help,

Zach
 

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As has been recently discussed in recent threads, try using a generous amount of WD40. Shoot into the shifters using the plastic straw.
Also make sure the cable is properly attached to the rear derailleur.

Al
 

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Before doing that, are you sure that the shifter is actually the problem? You should be able to tell whether it is pulling and releasing the cable like it should by testing the tension at the exposed sections (i.e. along the down-tube).

What shifter are we talking about anyway?
 

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Qstick333 said:
I'll try the WD40, any particular points to make sure I douse or just get the whole thing?
Yeah, squirt it in through any opening. I do it with the bike upright and then again with the bike upside-down.
If this doesn't fix the problem you may need to replace the cables and housings. Shimano has a kit for this and it is an easy job. Always replace the shift cable housings when replacing shift cables. If the old housings are the correct length cut the new ones the same length. The small housing just before the rear derailleur is often a problem because it picks up lots of dust, mud, water, etc. Be sure you get a clean cut at the ends of the housings.

Al
 

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Discussion Starter · #6 ·
I tried the WD-40 gig and replaced the cable and housing tonight. No luck at all. I have installed my cables etc... for a while now so this problem has caught me off guard. It seems that the bike won't upshift from the 16-18---->12 (finally drops the chain 4-5 cogs at once) and is very slow elsewhere. . I made sure there wasn't an obstruction in the cable guide, double checked the housing lengths before installing, lubed the derailleur, besides the above mentioned approach, I tied all sorts of tension ideas, etc...

The Ultegra shifter seems to be releasing tension well, I really am at a loss. The whole setup doesn't have 200 miles on it and this just started. The hanger is definitely not bent.

Any ideas for a possible solution??????????/


Zach
 
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