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shifting problems (shimano 105)

by carl j
Sun, Feb 12, 2017 19:46
7

Hi All

Wonder if anyone can help.  Just bought a pair of second hand 105 shifters (quite old - 5600 series)

Problem is with the 10 speed shifter - it changes down quite nicely, indexing from the highest gear to the lowest, however when I change up a gear, it simply drops to the highest gear.

I'm wondering whether I've installed the cable correctly, or if it's simply a dud.

Anyone had any similar experieinces?

Regards

 

Carl

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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7 comments

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FMOAB | 7 years ago
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I agree that it sounds like a gummed up shifter.  Persevere with it, take it off the bike put it in a freezer bag and saturate it with GT85 and leave it like that for a few hours, shaking it occasionally and working the shifter.  That will probably do it.

If that doesnt work put it in a bath of warm degreaser and agitate it as before.  I have the luxury of having an ultrasonic cleaner, which you can get for about £20, they are fantastic for sticking shifters, mechs brakes and even for OTT chain cleaning.  

If you go the degreaser route, make sure you oil the shifter well afterwards, ideally with something containing PTFE. 

Avatar
The _Kaner | 7 years ago
0 likes

upgrade to 5700 10 speed STIs.....Ive a new/(unused) set + cables/outers sitting here....

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dottigirl | 7 years ago
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Maybe a blast of air then followed by GT85.

I unwisely took mine along to local sand dunes when back in Wales. They've never worked the same since!

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Acm | 7 years ago
0 likes

It sounds like the pawl isn't returning after you've released the shifter to stop the ratchet mechanism dumping all the gears. The only thing you can realistically do is to try wd40 or some degreaser to loosen is off. Those Shimano shifters don't lend themselves to bring torn down (they're not too hard to take apart but nigh on impossible to get back together), so if you can't get it to free up with degreaser then it's probably toast
It might not be that the grease has clogged; it might just be a broken spring, which is also a massive pain to fix unfortunately

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carl j | 7 years ago
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Cheers for your tips.

I'm going with the lubrication idea when I next get the chance.  I've read the older 105 shifters used a grease that is quite heavy and becomes cloyed over time.  At least that's what I'm hoping.

Just to clarify, it indexes nicely going from small cogs to big cogs (high to low in my mind), but when indexing from a big cog to a smaller one, it simply dumps itself into the smallest cog/highest gear.  I'm hoping it's just a sticking pawl!!

Avatar
. . | 7 years ago
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Are you saying it jumps from the biggest rear cog to the smallest in one go?  If so, I can only think the shifter is broken.  Perhaps give it a good internal spray with GT85 in case some grit is stuck in there.

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hoffbrandm | 7 years ago
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Always get confused with different peoples interpretation of changing up, down, high and low...

Used to have 105 and came across a modecum of problems over the couple years I used it/destroyed it. (I'm not nice to gears)

My expirience is when changing to a smaller rear sprocket - loosening the gear cable.

The issues I cam across were:

- Lubrication of parts inside shifter because it was sticking.

- Having too short a cable

- Bent Hanger

- Not indexing using the GCN video (https://www.youtube.com/watch?v=Bbk5RcH0bbQ) and general indexing lack of understanding.

 

Hope that helps maybe?..

 

 

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