Help with rear derailleur not shifting high gears very well

amityweb

Hi. I was wondering if anyone can give me further ides about this before I take to a bike shop...

My rear gears wont shift very well in the lower cogs. I have to click a few times to get it move up and down. Sometimes 3 clicks to get it from the smallest to next cog. When I click first I cant see any movement. I do feel it tensioning a little with my finger, but just not enough, hence 3 clicks. Then sometimes it wont come back down to the smallest cog. Larger cogs is OK. I have read loads of posts, and watched loads of videos, and dont what I can, but still no good. Its a Sora.

1) Put new gear cable in, and ferrules, because the ferrule into the shifter had split and the outer housing wires all poked through into the shifter, I thought this was the issue but even after new cable and ferrules still have the issue...
2) Cleaned out and oiled up the shifters and the derailleur and chain and cogs
3) Set high and low limits OK. Dont think thats the issue.
4) think I have set the tension OK... set the barrel all way in, put it in highest gear (smallest cog), and clamped the cable
5) checked outher housings, they slip OK, so dont seem clogged up
6) fine tuned using the barrel then to get the tension right - although this is what is not working, just cant do it!

I click the shifter once which should move it into the second from smallest cog but it doesn't shift, so I adjust the barrel until it does. But then it doesn't shift back down. So fine tune the barrel so if shifts down but then it wont go back up. Even when it moves with the barrel adjusted, the shifters wont shift it necessarily. I have been at it for hours and hours! If it can shift up it wont shift down and vice versa. This is all on the smallest cogs. Its OK on the large cogs I think. So the cable is tensioning OK as I shift to large cogs, but coming to the smaller ones, the derailleur just doesn't pull in far enough, unless I really slack the cable, but then I dont have the tension to move back up. I dont get it!

So I am starting to wonder if my derailleur is knackered. It seems to me when the cable is slackest, the derailleur is not pulling in strong enough. Slackening it is OK, but then its too slack to move up. Maybe the spring is knackered or something, because I was thinking if its tight enough to move up, then the spring is not strong enough to pull back. Dont know though. I have cleaned out the derailleur and oiled it up but still no joy. Or it maybe its not straight as I have had bump on it, but I cant see that its not straight, seems OK.

Any thoughts?

cooldad

Are you sure the shifter was in the right gear when you clamped the cable.

Loosen it all off and start again.

Make sure the cable is clamped in the eight place as well.

Very unlikely to be the mech, especially iff you've been doing random faffing.

sungod

first step is to check the cable routing is correct for your specific rd, even slight deviation from the correct path can cause problems

the manufacturer's website will have instructions for each model

you say it's had a "bump", maybe the hanger is bent, that's hard to judge by eye, if you don't have an alignment tool then it may be simplest to get lbs to look at it

amityweb

cooldad wrote:

Are you sure the shifter was in the right gear when you clamped the cable.

Loosen it all off and start again.

Make sure the cable is clamped in the eight place as well.

Very unlikely to be the mech, especially iff you've been doing random faffing.

As I stated I read loads of web sites and watched videos so did it correct so not sure why you think I was random faffing. Sorry if my post didn’t explain I took the steps correctly but still no joy.

cooldad

amityweb wrote:

Snip....

I have been at it for hours and hours!

Snip...

Any thoughts?

Just a thought....

pilot_pete

Could be any of number of things.

1. Start again, going back to basics.
2. Check the hanger for correct alignment, adjust as required. Set the B screw as per manufacturers instructions to get the top pulley nice and close but not touching your biggest sprocket.
3. Make sure the cable inner and outer are not damaged in any way, from obvious to less obvious/ hidden. Things to check are otters correctly seated at each location, inners not frayed or kinked, routing as per manufacturers recommendation (no loops that are too tight etc).
4. Back off inline adjusters so they are not at their limits and ensure they are free to work and adjust correctly (ive had one turn freely but not actually do anything).
5. With the cable off the rear derailleur, click all the way to what would be the smallest cog, which is your starting position.
6. Adjust the limit screws to ensure you can at least get the derailleur to line up with top and bottom gears (just to make sure you are not causing an issue by having the derailleur too far inboard at the limit before clamping the cable or overly restricting derailleur movement preventing getting lowest gear).
7.Holding tension on the free end of the cable shift all the way up and down to see if you can feel any undue resistance. Shift back to the start position pulling free cable back through (as there is no derailleur spring action to pull it through).
8. Correctly route the inner cable and clamp it on the rear derailleur. Before clamping it ensure you have a little tension on it to remove any free play, but don’t pull it too hard and end up with excessive tension. Clamp to specified torque.
9. Follow manufacturers guidelines which normally mean shifting up to something like the fourth or fifth cog making sure you count the correct number of clicks to get there. If you have excessive play which means you need excess clicks to get to the correct cog, shift back to the smallest and take out any slack with the inline adjuster. As soon as you shift you should get immediate derailleur movement. Shift back to the recommended cog (like I said, usually fourth or fifth or thereabouts).
10. Ideally with the bike on a stand, view the derailleur from behind and look to see if the chain line is directly below the gear that you have selected. Adjust the derailleur adjuster to move the derailleur in or out as required.
11. Now try shifting through the gears. If the derailleur struggles to lift the chain up to the next biggest cog it means you need to adjust the cage inwards slightly using the adjuster on the derailleur. If the derailleur struggles to shift the chain down onto the next smallest cog then it needs adjusting slightly outboard.

If after you have done all this it still doesn’t shift correctly you have an issue with a component somewhere, which could be the internals of the shifter ratchet mechanism, or the rear derailleur itself (possibly damaged from a crash, bump etc.)

Assuming nothing is actually damaged it is usually a cable drag issue (due to corrosion, a kink, wear, incorrect routing) or incorrect setup (adjustment of B screw, cable tension, alignment etc).

Other things to consider (as I am assuming nothing is excessively worn) are chain wear, cassette wear/ damage, jockey wheel wear (ive had that before where the teeth had actually worn to spikes!), gunked up shifter internals etc.

Hope this helps.

PP

perfectmark

I had a similar issue a while back, after a few weeks of trying to sort it, I finally gave in and took it to a bike shop. Turns out the rear Derailer was slightly bent, so just got them to install a new one.

amityweb

I have had it fixed by my LBS, and it was just two simple things! One of them I was so tempted to do but thought it was OK not to, the other one I had no idea....

1) Changed the cable outers - I almost did this myself, I have some spare, but I moved it myself on a slack cable and it slipped fine so thought to keep it. But the LBS said a new one would be smoother

2) I used a £2-£3 halfords gear cable because Amazon let me down with an ordered one and wanted one ASAP so popped to Halfords... the LBS said Halfords gear cables are no good, they are too course! So he replace it with a better £5 something one which would slip easier due to being less course.

So I had too much friction along the cable, both the above reduced friction.

After he did those two things the gears shift fine. And I am amazed how much it didnt slip with the old outers and a Halfords cable. I cant believe Halfords can be selling gear cables that dont work. He said they're OK for sh*t bikes but not proper road bikes!

So live and learn, such simple things can stop gears shifting.

cooldad

Most likely it was the outers that made it work.

Halfords cables are probably basic steel, and stainless or coated are better, but they still work, like millions of other cables. 'Coarse' is nonsense.