Barrel Adjuster on the rear derailleur. Need help.

[d.vader123]

Okay. I need assistance with another mechanical question. My rear derailleur has been properly adjusted. High and low limits set but when I ride especially up a hill, I shift to the larger cog. Unfortunately, the rear derailleur shifts back to a smaller cog and sometimes the smallest cog when there is some load.

I feel that it might have something to do with the barrel adjuster so I took a closer look at it and the screw that is supposed to be in the derailleur is not on.

So turning the barrel adjuster was doing squat. I went home and tried to put it back in and I can only get the screw into the derailleur thread just a little bit.

But basically, when I try to turn it counter-clockwise, the screw in the barrel adjuster comes off the rear derailleur rendering the adjuster useless.

What should I do? Will this be an easy fix? Did I break something???

Lost and confused.

Edit: I am using 105 rd with friction down-tube shifting on a 9-speed cassette 12-27.

[Mike748]

Sounds more like you don't have enough friction on your shifter. A stripped barrel adjuster will make it harder to fine tune index shifters. But in your case with friction, just screw it in so it stays put. Then tighten your shifter mounting screw so it holds better against the RD spring.

[Peter P.]

Mike748 has it right; your friction shifters aren't providing enough friction. This could be due to a couple reasons.

It's okay to lube the friction washers in the shifters but usually they're smooth enough without lube. Try wiping them dry. Do one at a time and pay attention to the orientation of the parts.

It's quite possible you've assembled your shifter incorrectly so the friction washers can't do their job properly. Since you haven't complained about the front shifter, disassemble it, laying out the parts in the proper order and paying attention to their orientation. Then do the same with the rear shifter; you might find something doesn't match.

Some plastic washers on downtube shifters can compress with age and lose their ability to provide sufficient friction. You can try roughing them up with sandpaper, or try finding replacements.

You could also be missing a part on the rear shift lever such that the nut which secures things bottoms out before it applies pressure to the friction washers. Sometimes just adding an additional washer provides the thickness you need. You could experiment using some of the washers from the front shifter.

Regarding the rear derailleur: You have a couple options.

1. A good bike shop can re-tap the threads using a BOTTOMING tap. Examine your barrel adjuster first to see if the threads are damaged, otherwise you'd be wasting your time. You could buy the tap and do the job yourself for much less than the price of a new derailleur. Bring the screw to a hardware store that sells taps and they can match the thread needed; it's metric.

2. Replace the rear derailleur. Stripping the barrel adjuster threads is rare but I suppose it could happen. Hold on to that derailleur though; many of the parts come in handy.

[fjaws]

Sounds like at some point you accidentally backed the barrel adjuster all the way out of the RD and the threads are now stripped.

If the barrel adjuster isn't engaged in the threads then your shifting will certainly be all over the place.

See if you can clean up the threads in the RD with a tap so the barrel adjuster will go in normally instead of just a couple turns, readjust everything, and it should be good to go.

[d.vader123]

Sounds like at some point you accidentally backed the barrel adjuster all the way out of the RD and the threads are now stripped.

If the barrel adjuster isn't engaged in the threads then your shifting will certainly be all over the place.

See if you can clean up the threads in the RD with a tap so the barrel adjuster will go in normally instead of just a couple turns, readjust everything, and it should be good to go.Thanks. Actually, the barrel adjuster was threaded in a bit. It just isn't in all the way because I am unable by hand to get it in all the way.

I am wondering if I should try to force it through effort to thread it in there. It is engaged though. I just can't get it to thread all the way through with my hands.

[oldpotatoe]

Thanks. Actually, the barrel adjuster was threaded in a bit. It just isn't in all the way because I am unable by hand to get it in all the way.

I am wondering if I should try to force it through effort to thread it in there. It is engaged though. I just can't get it to thread all the way through with my hands.

Darth, darth, go to a bike shop, have them repair/tap the RD barrel adjuster threads, install the barrel adjuster properly so you can use it.

[d.vader123]

Darth, darth, go to a bike shop, have them repair/tap the RD barrel adjuster threads, install the barrel adjuster properly so you can use it.Thank you O.P.T =)

I actually was able to do it myself. I reinstalled the barrel adjuster and then adjusted my rear derailleur again. Everything works now. The problem was the barrel adjuster and I was able to get it in the threads and screw it all the way into usability.

Thanks all!