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Shimano 105 - Rear Derailleur Problem
This afternoon I removed and cleaned my shimano 105 cassette on my road bike. When I put the cassette back together and back on the wheel, everything fit together per the documentation on the shimano web site except for the absence of one spacer that was on the instructions, but was not on my bike (the spacer to the left of the largest ring).

I put the bike on my trainer, and tried testing by hand the pedaling and gear shifting to make sure everything was working. I noticed that it would not shift into the the top ring, and it was shaking/clicking on the bottom chainring.

I tried turning the barrel adjuster on hone rear derailleur, resulting in no change in the shifting problem.m eventually, I noticed that the barrel adjuster was no longer attached to the derailleur. I tried reattaching it, but no change.

I tried adjusting the cable into the read derailleur (unscrew, make the cable tighter, screw back in), and now the gears are stuck in only the smallest ring.

Other than doing the walk of shame to my local bike shop, can anyone recommend a course of action that I could take to repair this problem? I would recalling like to make this repair myself, but I only seem to be making it worse.

Thank you.
If I am reading you correctly, it sounds like you have a 7 speed cluster on a hub for a 8speed or so. how many speeds is your 105 cluster? the spacer would go on before the cluster, did you do that?. Maybe post a pic of what you have.
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
Thank you for the quick response! I have a 10 speed.(http://tinyurl.com/lkkso8j)

I've attached three pictures of the cassette.
following the tech docs, the set with 12t small should have 15 pieces, looking at your picture the thin ring right under your lock ring should go on first, then the main cluster, then spaced as you have them already. your lock ring grooves will lock in the grooves of your smallest cog. check your High/low limit screw adjustment, attach cable and set the shifter. if you never detached the cable, undue the change you made to the barrel adjuster.
It may be better to start fresh at this point. set H/L limit, attach cable, follow tech docs to set properly
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
Thank you! That seems to be working better now I wonder what happened to that 15th part...

I will start from scratch on the cable/shifter next.

Have a nice evening!
It could be a slight design change mid run who knows. Did you buy the bike new or used? If used,someone could have swapped cogs from another set.
as long as the spacing is the same from cog to cog and your lockring does not bottom out before snugging everything up you should be fine.
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
It was purchased new about 15 months ago.

The bike pedals, but is stuck in the second smallest cog in the cassette. Right hand shifter will only shift down once, but the chain does not change gears. Shifting to larger cogs, the shifter does not move at all.

I'm not even sure where to begin to correct this.
Got it working again!

The barrel adjuster was not screwed in properly. Once I got that in correctly, the shifting worked again.

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