Hi guys , since i got my roady i never changed my cableholders. After a bunch of time i decided for a liiiiittle upgrade by changing all old parts and adding some new color. The aestetics look pretty cool but here the problems:

• Somehow those two little plastic thinghy similat to those o-rings inside there are broken and now i can't adjusting the brake there.

• My shifters does not work properly since when i swap to the middle gear the chain start bouincing (no , all teeths are in good conditions). Other gears works pretty fine. Maybe because i used those cableholding ending cap even in shifting cables?

Dammit... i feel a bit rusty into those little mechanic's problems...

If this is just the rubber friction ring, I think that the part is not just "similar to an o-ring", it actually IS an o-ring. Find the right size at the hardware store and you should be fine.

Or are you missing the whole adjuster?

Not sure I understand the problem with your chain. Is the "middle gear" the middle chainwheel (front) or a middle cog (rear)? If its the rear, first make sure that the derailleur hanger is true and not bent or distorted. If this is indexed shifting, the key is to get the zero-tension state (small chainring or cog) of the offending derailleur correct. And make sure your shifter cable is intact (not wearing way or partially broken) and make sure it's tight.

Beyond that: I'm a little rusty with the mechanics problems, too. I am sure that others here are more expert and can help you with more certainty.

I didn't think of the O ring solution, that's a good one to remember.

The Park Tools website has a lot of easy and sensible articles on how to work on your bike. Maybe worth a read there?

My personal approach is that when I find I'm not solving a problem, I just take it to my bike shop and ask them to have a look. Over the years, I've worked to maintain a good relationship with them, spent a bit of money there (as well as on the internet) and this is one area where that pays off - they're always happy to not only work on my bike (of course, seeing I pay them to) but also to explain what it was that was wrong and sometimes to help me to fix it.

middle gear = middle gears in the cassette.
Is that probably because i used cable's cap at the end of the cable-holder for shifting?