hi565

yes, probably mental help at the moment...

So here is the situation. My friend snapped his Derailleur hanger in half and I said I would put the new hanger on and get ever thing back to normal.

Well I got the hanger and the RD on. But here is where it just pitfalls...

I got the chain back on, then i handled the cables. I got everything nice and tight. So then i try to start adjusting the derailleur so things start working smoothly again. (after putting the RD back on things became kind of choppy) So I started to work with the barrel adjuster to find the right tension. I personally didn't feel like I was doing much. I noticed something though...I would shift down into the smallest cog, and then shift one more (as if I was shifting into an imaginary cog) and instead of not shifting, it shifts then everything becomes out of line. I tried working on the limiting screws, but all that got me was no where really. I tried working on the barrel adjuster. I tightened it a good amount, then I found out I couldn't shift into the largest cog, so I loosed the adjuster. Now the chain wont shift onto the second to largest cog.

Everything is a mess, I really need help, guidance something in getting me through this. I need to get this bike back to normal so I can give it to my friend. (Now I know some of you may be thinking, why the heck is he doing this to a friends bike and not his? Well honestly I was not expecting so many small little problems that would just add up, plus I forwarned my friend that it was a learning time for me, and that it was going to take a while.)

I hope this made sense, and if it didn't please tell me and I will try to clarify it up.

THANKS!

mtbikerinpa

Check to see if you have everything in alignment. Sometimes the hanger mounts or the derailleur itself can be bent in addition to the hanger that was replaced. You will also have to check and adjust your range of travel limit screws on the derailleur body. They will be the small screws marked H(High, or small cog) and L(Large cog, low gear). If the mid gears work fine but you cannot get the extremes, then back the appropriate screw out or in until it works right. Do not allow any more travel than you need, or else it can bite you with an overshift at a bad point.

Old Hammer Boy

You can find this information on the Park site, but I'll briefly go through the procedure as I do it.

1. Release all tension on the shifter cable by shifting brifter (or whatever shifter you have) to highest gear (smallest cog). Do not connect cable yet, and make sure chain is on large chain ring.

2. Make sure chain is on smallest cog. If not, release some tension on the adjuster screw.

3. Fine tune the limit screw so chain is centered on the smallest cog.

4. Shift to small chain ring. Now peddling (slowly) pushing the RDR in towards the wheel until it engages the largest cog. Be careful to not over travel and contact spokes. Be careful with your fingers, too.

5. Fine tune the limit screw so chain is centered on the big cog.

6. Adjust cable trimming adjuster about midway, or a little less.

7. Shift the chain ring back to large ring, allow RD to move to smallest cog once again.

8. Hook up the cable leaving hardly any slack.

9. Run through the gears and trim if required (1/4 turn per try should be enough).

That should do it. OHB

Mentor58

I'll be the first to let you in on a secret... Everything you need to know about basic (and some not-so-basic) bike repairs / adjustments can be found at Park Tools Web Site Adjusting a derailler is fairly easy most of the time if, and only if, you do it 'By-The-Numbers' according to the directions at Parks.

I've made the mistake of randomly twisting, turning and testing until mine was so buggered up that I didn't think I'd ever get it right. Somebody here let me know about parks, and by going back and adjusting it exactly according to the directions at the site it's slick as snot right now.

Steve W.

DannoXYZ 

This is a sure sign of excess cable-friction and you're off by one click on the cogs. First set the shifter into smallest cog first and make sure that the RD drops the chain into the smallest cog. Then adjust tension so that it goes up into the 2nd cog on the very first click. You'll find that with your configuration it doesn't and will require another click to shift into the 2nd cog (and the shifter's on the 3rd cog now). That's why you couldn't go into the largest cog, you were already on the last click on the shifter with one more cog to go.

Deanster04

If all else fails take it to your LBS (one noted for good mechanics) and have them check for your hanger alignment. It takes a special tool and just a few minutes to check. I am assuming the frame is Aluminum. Good Luck.

Retro Grouch 

Agree. If a derailleur doesn't respond to normal tuneing, check to make sure that everything is in alignment. That's almost always where the problem lies.

hi565

I do know about the park tool site, and I do know about sheldon. I have looked at both. Neithor seemed to have really helped me too much.

supcom

Bending a hanger is generally the result of excessive force against the derailleur. Snapping one off altogether is likely to have put such trauma on the derailleur to have bent it out of alignment. Unless you are using a brand new derailleur I would suspect this as the cause of you difficulty. Adjusting the rear derailleur isn't that tough. STI stuff is pretty forgiving so if you get it close it should work reasonably well. But if something's not aligned properly, all the fiddling in the world won't help it.

The limit screws are a red herring. They just prevent overshifting the derailleur off the cogs. While a bad adjustment here may prevent the chain from getting to the extremes of the cassette, it has no effect on mid cassette performance. This is almost exclusively a cable adjustment issue. But, all assumes good alignment.

hi565

Thanks everyone for commenting.

I tried working with the limiting adjusting screw to fix the over shift into the ghost cog problem. That did not help much. But something I noticed is that the gears are almost pushed over by one. So instead of the chain being able to shift onto the biggest cog, it shifts past the smallest cog. I am trying to figure out how to almost push everything up a cog, so then I can shift onto the largest cog with no trouble, and there wont be any over shift on the other side.