DRietz

Hey there bike forums member people! I had a bike up for sale, and I had somebody interested. In turn, I went down to the garage, put the bike on the stand and decided to fiddle with derailleurs. Now, my shifting on both derailleurs is berserk and I am totally frustrated an about ready to melt it down and pawn it off as good aluminum.

Essentially, my rear derailleur won't shift up with 1 shift, but takes two or three and then goes to that corresponding gear. It does shift down, though.

And then my chain ring shifts up through the rings, but won't shift down from the large to the middle without having to shift down to the small and up again.

Please help. I'm an idiot, hence the user title. And due to my idiocy, please be specific (i.e. turn this screw in or, turn this barrel adjuster out)

Thank you so very very much. The component set is rather old and kind of crappy. Shimano Altus. It's an 18 speed townie/touring trek something or other.

mzeffex 

For the rear, turn the adjusting barrel on the rear derailleur and/or shifter left. And for left, that is, looking head on. So stand behind the bike and look at the rear wheel. From that angle, left. For the shifter, face the front of the bike. That left. For the front, turn the adjusting barrel on the shifter right. That is, facing the front, turn it right. That should do it.. assuming you didn't move the front derailleur around or unhook the cable.

Panthers007

I won't ask you why you did this - only that I hoped you learned a lesson. Now I propose you continue your education. Get some new gear-cables and cut-to-length (bring your old housing) at your LBS - stainless-steel cable is far the better - and study-up on installing & repairing both front and rear derailleurs here:

https://www.parktool.com/repair/readhowto.asp?id=64

and...

https://www.parktool.com/repair/readhowto.asp?id=75

And some videos to demonstrate the written:

https://bicycletutor.com/adjust-rear-derailleur/

and...

https://bicycletutor.com/adjust-front-derailer/

OR -

Take it to the bike-shop and spend some money. I would suggest to all that a good pair of bicycle-specific cable-cutters be a needed evil. They aren't cheap - but they will last a lifetime with proper care and common-sense. Shimano one's are about as good as they get.

mzeffex 

Panther, he doesn't necessarily need to cables. I would assume that his still work as it does in fact shift.

Panthers007

I always recommend people have cables on hand whenever they are faced with a derailleur problem. Heck - I keep a shelf full. All different flavors!

mzeffex 

Sure, but for this problem, I don't see it necessary.

Speaking of your cable inventory, I think I am the least prepared shop employee ever. I have so much bike schwag I don't need; wheels, tires, pedals, cleats, hydraulic brakes... but when it comes to the necessities.. don't even have a spare tube, let alone a cable. It's always the one day the shop is closed that I get a flat. Then I gotta spend $7 on one instead of 2.

DRietz

Alright, I'll give it a try tomorrow. Should I turn in 1/4 turn segments and try? Also, does it matter what gears I'm in when this is done?

Yes sir, I did learn a lesson. And thanks for the references. Click. Bookmarked.

operator

It might be. Whenever you have shifting problems, after a proper full adjustment is done you change

1) Cable + housing
2) Check rear derailleur hanger alignment
3) Check worn chain/derailleur

This things can happen out of order, a worn chain or one that isn't lubricated can also cause craptacular shifting.

mzeffex 

Yes, quarter turns. Put it in the gear(s) that aren't working, one by one. Say it's trying to go up to the second smallest cog from the smallest cog, put it in the smallest, and turn the adjusting barrel right a little. Spin the cranks. Fixed? If not, repeat.

Retro Grouch 

Start over.

Disconnect both shift cables from their respective derailleurs. Pull up the Park tool website and start from the very beginning.

Once you get derailleurs well and truely screwed up, there is a tendency to make continued misadjustments in order to counter previous misadjustments. The solution is to start over fresh. The Park Tool website has well written step-by-step instructions.

cbchess

+1

Instead of chasing this problem from the middle, disconnect the cable and start at your top most gear and try to get it right from there.

operator

E.g Post #3.

DRietz

I didn't do anything having to do with the cables. Here's the break down of what happened:

1. Bike went on stand, and I shifted the chain ring to the top and the cassette to the hardest gear.

2. Began spinning the cranks, and tried shifting down on the chain ring to see if the bike had remedied itself. It hadn't. So, I started doing 1/4 turn increments on my outer limit screw.

3. Above did not work, so I turned the outer limit screw back to where it was originally. Then, I shifted down on the chain ring to the smallest ring and tried shifting the cassette to the easiest gear, but it would not shift up.

4. Fishy, I thought. I hadn't touched that derailleur at all, ever. So I started mess with the barrel adjuster on the derailleur, never touching any adjustment screws.

5. I ended up here.

Retro Grouch 

Trust me, my advice is the quickest way to get it fixed.

wrk101

+100, this will usually be a lot faster than other methods. Start over, do it right, step by step. I recently bought a garage sale bike, where the FD refused to shift to all three chain rings. I disconnected the cable, followed the steps, and had it working well in about 10 minutes.

Cassave

I have a few questions;

Has the bike been sitting for a longtime, unused?
Where the gears working ok the last time the bike was ridden?
Has the bike been exposed to the elements or stored inside and dry?

The front shift working ok in the up direction and hanging in the down direction sounds like a
sticky or binding cable. Will the front shift properly if you pull the cable along the downtube (like a
guitar string) instead of using the shifter?

Will the rear shift one cog at a time if you use the same method i.e flex the cable along the downtube?

If true to either question then the problem is likely in the cable run from the shifter to the downtube cable stop.

vredstein

Rather than trying to learn the shifting adjustment process from a bunch of random posts here, try to find a video on Youtube. Type in "rear derailleur adjustment". You'll come up with a good selection of video tutorials. Much easier than deciphering the written word.

AndrewP

Your problem was friction in the cables. You probably didnt need to adjust any screws. However to eliminate the friction you will have to disconnect the cables at the bottom ends to clean the housings and cables with WD-40, then lightly lubricate. However if the ends of the cables have unravelled you should get new ones. Have the shop cut them to the same length as the old ones. Follow the links provided for reinstallation.

Al1943

+1
And don't leave ANY steps out.

DRietz

OK, OK. So the general populace wants me to start over. I suppose I will, but the LBS is a LPOS. Two derailleur cables are going to cost me $15. I went in there today and asked about it. This sounds like an awful lot to me... shouldn't they be cheaper than that? Also, what should I do with all of my barrel adjusters and stuff before starting? Turn them all in?

Dan Burkhart 

If they are selling you quality stainless steel mandrel drawn cables and lined housing, the price is reasonable, or even cheap. If they are pre packaged department store quality sets, then yeah, it's too much, but you should avoid those anyway.
I like to start with the barrel adjusters about 1/3 of the way out.Gives you room to adjust both ways.

Al1943

Always replace the shift cable housings when replacing cables. The housings are equally as important.

Al

DRietz

But my housings are fine. No frays or anything. I think just some new cables and grease will do the trick.

Dan Burkhart 

Short of sending a fibre optic scope through the housing, you cannot say that with certainty. Just because it looks OK on the outside says nothing about the condition of the liner. If there is friction in the cables, you should replace both. If you are determined not to replace the housing, just run some light oil into it and don't bother replacing the cables either. It will likely work better than it does now for a while, but the real fix is replace cables and housing.

DRietz

Well, my rear derailleur shifts like magic now. No cables replaced, it was purely a tension issue.