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Shimano 105 shifter won't shift down

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Shimano 105 shifter won't shift down

Old 08-20-10, 01:39 PM
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Shimano 105 shifter won't shift down

Just as I got within 2km of home on my daily ride just now, I became unable to shift down to the smaller chain ring on my Caad 9 5 (full 105). The inner lever doesn't have any affect on the cable beyond moving it perhaps moving the FD about 1mm if I first tension the cable all the way with the other (upshift) lever.

This happened suddenly, there was no notable noise or feeling, it just stopped working. The cable does not have any slack in it and I am unable to pull it one way or the other by hand with the exposed cable beside the downtube. I do keep the FD lubed regularly, in fact yesterday I gave it a few squirts.

Any help would be appreciated - should be under warranty (I think) if it's the shifter, but I hope it's something I can fix!
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Old 08-20-10, 02:46 PM
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I would check to make sure the shifter is even still pulling cable by loosening the cable to the derailleur and feeling by hand as you shift (apply some tension by pulling with your hand).

If the STI lever is borked then you'll probably have to replace it, hopefully under warranty. The newer stuff is almost impossible to fix yourself (mostly due to difficulty in getting parts, plus needing specialized tools) and seemingly runs with the assistance of black magic.

other stuff (long shot, in my opinion) that might be to blame:
-damaged cable housing (check the ends beneath the ferrules)
-incorrect cable routing through the pinch bolt
-incorrectly set limit screws
-head of derailleur cable dislodged within STI lever mechanism
-foreign object jammed within STI lever mechanism
-bottom bracket cable stop broken/messing with cable in some way
-broken barrel adjuster(s)
-foreign object jammed in actual front derailleur mechanism

Last edited by cbfight; 08-20-10 at 02:54 PM.
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Old 08-20-10, 03:18 PM
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Well the little ring is the default position so you can rule out just about every cable and adjustment issue besides it hanging up. Unless you do it intentionally, there is no way to get the adjustment to lock it on the big ring - it can't slip that way. Unless something became damaged, I would likely rule out the derailleur and adjustment screws as well.

Try this (assuming 5600 105):
1. Release the front derailleur. if it moves freely back to the small ring, you can rule out anything with the derailleur.
2. If the cables run exposed along the downtube, grab it in the center of the downtube and make sure it moves freely under the bottom bracket.
3. roll back the hood on the left shifter from the top. on the outer side, there should be a slot (or you may possibly see the end of the cable) where the lever attaches to the body. actuate the lever in whichever direction exposes the ball end of the cable... you'll see it a few mm inside the shifter
4. try to backfeed the cable from where the housing attaches to the downtube and see if the end pops out of the shifter. if it moves freely once the end clears the shifter, then your issue is in the shifter and you're screwed. they are non-serviceable.

if you can determine a slight issue in the shifter you may be able to fix it but no guarantees. that's the one benefit campy has over shimano and sram IMO

Last edited by andrewluke; 08-20-10 at 03:21 PM.
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Old 08-20-10, 03:46 PM
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Thank you both for the responses. I've removed the cable from the FD and ensured it moves freely, which it does, so the FD can't be the problem. The cable was secured well before I took it out. With the cable out, ti moves freely around the BB and up the downtube (exposed). Pulling on the cable (away from the shifter), it doesn't budge, and pulling it while trying to shift also does nothing.

I rolled the hood back and couldn't see anything cable-related inside, but I've never looked inside one of these before. I took a video of what I tried with the hood rolled down, it seems to have gotten more screwed up. The parts where I'm pointing the camera at the cable, you can see which lever I'm trying, and I'm always pulling on the cable when I try a lever.

Video: https://www.flickr.com/photos/gavinsmith/4911560788/

This really seems busted to me, but that surprises me - I don't race, I do it for leisure and fitness, I don't ride it hard, I ease up when I shift, and it only has ~2000km on it. I hope I'm under the LBS's warranty - I know they do warranty tunes for two years after purchase, it's been about 14 months. I just hope I don't have to deal with Shimano, shipping parts, etc - I ride every day.

Thanks for your help, let me know what you think!

(Edit: Headed to the LBS now, they close in an hour or so and I can't do it tomorrow. I'll be sure to give an update.)

Last edited by GSmith; 08-20-10 at 03:50 PM.
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Old 08-20-10, 05:13 PM
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Okay, all done - the shifter was mangled. I don't have an exact technical explanation, but basically the gears within the shifter were not engaged at all - just wore out. After 2000km. Kind of disappointing. Here's to hoping this one lasts me a little longer than that, or at least until I can move up to Ultegra.

Actually, I was lucky - the LBS is handling the warranty with Shimano, even though they aren't obligated to at all. Didn't cost me a dime and no more than an hour even though I'm outside the one year mark.

Thank you for your suggestions!
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Old 08-20-10, 07:47 PM
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Really sorry to hear that, but glad you got it replaced so quickly. It's such a shame that as shifting technology advances, do it yourself repairs and even aftermarket parks become more and more hard to come by. I have a pair of ST-2200 shifters I keep on my commuter bike that I have brought back from the grave more than a handful of a times, but my second generation 10 speed dura ace shifters are sure to be replaced at the first sign of failure.
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Old 08-20-10, 10:24 PM
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looking at the video, it appears that I have my generations mixed up and there is no easy access hole like the new Tiagra and 6600 Ultegra have. Sorry for the mislead on that. Sorry to hear about the shifter too... if it's not warranty, you can probably find one on ebay for cheap.
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Old 04-28-16, 11:45 AM
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same issue on ultegra sti

Perhaps its a bit late to comment on this thread but i felt like i had to. My left shifter was working properly then all of a sudden during a ride i could no longer use the inner ring. Got home, unmounted the sti from handlebar, and started looking for some wierd mechanic movements. Didn't find any. It all seemed like was working ok. No loose parts or bolts or screws. For some reason the mechanism wasn't working. With the help of a maglite looking from the bottom up i could see quite a few springs inside. I noticed also there was one spring no matter which lever i pressed was not moving. That spring is attached to a tiny little piece of metal that has two screws securing it to the sti body and is hidden under a plastic cap on the outside of the sti. I took some pics but as I'm new to this forum not sure if i can post it or even how to do it. Anyways, the hook which the spring uses to hang on to that tiny metal piece was broken. It could no longer pull back the mechanism to its original state. all i did was to fix the hook and reattach it to the metal piece and voi la. It worked again!!. Searching for this kind of problem gives me tons of google entries. Looked through many of them and no one could tell for sure what the problem was.
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