gears won't tune up properly

equivariant

Looking for suggestions. I have adjusted and tuned the rear derailleur several times before with no problems so I know how to adjust the rear derailleur

However I have just replaced the cable (old one snapped mid ride) and no matter how I adjust I cannot get the gears tuned just right. I set the limit screws and adjust the cable tension in the standard way but when I want to shift to a bigger sprocket, I have to click up two notches on the shifter to get the chain to move up by one sprocket. Then once it has moved I can release the tension by one notch and the chain runs smoothly as it should. No matter how I adjust the cable tension I can't seem to get the chain to move properly with just one click of the shifter.

Any thoughts on what might cause this (hopefully my explanation is clear). Its standard tiagra 10-speed shifters and derailleur

petethedrummer

Is the derailler screwed tight to the hanger? If it is screwed tight, is there play?

smacl

Did you replace cable outers as well as inners? Sometime a poorly cut outer, or a crud build-up can affect shifting. Also check the derailleur hanger hasn't taken a knock.

Eamonnator

Tighten the cable tension, until the chain won't go into the smallest sprocket. Then gradually loosen tension until chain stays in smallest sprocket.
Might work.

Luxman

Make sure the cable is fed through the channel /groove on the underside of the bottom bracket. Outers should be changed with the inners if possible

Daroxtar

Was the chain on the small ring at the start of setting up?

equivariant

smacl wrote: »

Did you replace cable outers as well as inners? Sometime a poorly cut outer, or a crud build-up can affect shifting. Also check the derailleur hanger hasn't taken a knock.

Could be this - I did not replace the outers. Cheers

Fingers Mcginty

Are you sure your rear hanger isn't bent. Exact same thing was happening to me.

koutoubia

Replace the outer cable especially if the cable snapped.

07Lapierre

You need a new groupset!

man_no_plan

07Lapierre wrote: »

You need a new groupset!

Never mind that, new bike would be sure to sort it.

07Lapierre

Gears working OK, Replace the inner gear cable, now gears not adjusting OK.

If this is correct, then it's probably not a bent hanger etc.
I'd replace the outer cable, make sure the barrell adjuster is working OK and then I'd try adjusting the gears again.
If they still won't adjust correctly, then I'd start looking at the rear derailleur for wear. I'd also check the chain for wear.

How old is your groupset?

pm78

Had same issue. It was hanger.

Type 17

Firstly, check the hanger - it could be coincidental, or it could be that the change in the setup is now causing issues where you were "getting away with it" before. Other issues can be a worn-out chain or jockey wheels, but that's unlikely when the issue has appeared suddenly.

However, as mentioned, it's much more likely to be the old, unchanged cable housings being sticky - if you set the indexing up to work on the way up the block (small to large sprockets), your effort (your hand on the shifter) will be pulling the derailleur*, so everything will work ok, because your hand is able to overcome any excess friction of the sticky cable housing.
However, on the way down the block (big to small sprockets), the spring inside the derailleur is trying to do this work, and can't shift cleanly if the friction is too high in the cable (or the derailleur or shifter itself are stiff from lack of lubrication).

The reason that you currently can't shift up the block in one click is that you have (unknowingly) set the cable tension too loose because you were trying to ensure that the derailleur shifts down the block properly. That's why you should always set the indexing by shifting up the block, and only shift down the block to check that you haven't overdone it, or that the cable isn't sticky.

For a final check, I shift to the biggest sprocket and then go down one, and then look down from above and slightly behind the block to check the gap between the chain and the first sprocket - this gap should be the same on the links that are between the block and top jockey wheel as it is on the links that are still on the block.

*On 99% of derailleurs - a few work in the opposite direction, but for them, just reverse the directions and continue setting up as normal.

equivariant

07Lapierre wrote: »

Gears working OK, Replace the inner gear cable, now gears not adjusting OK.

If this is correct, then it's probably not a bent hanger etc.
I'd replace the outer cable, make sure the barrell adjuster is working OK and then I'd try adjusting the gears again.
If they still won't adjust correctly, then I'd start looking at the rear derailleur for wear. I'd also check the chain for wear.

How old is your groupset?

Most parts of groupset are fairly new. Brand new chain, derailleur a couple of months old. Cassette a few weeks old