Shifting - tried everything - won't work right - desperate

pastryboy

I am at the end of my tether here. I've spent hours on this. Got internal routing and I've:

Replaced gear hanger
Tried another cassette
Replaced all inner and outer cables

I can shift up through the cassette and I can shift down - all works fine. However, if I shift up one then down one then nothing is happening - the RD barely moves and needs another press to move down.

I'm not sure what else to try. Help

meanredspider

Have you checked the hanger alignment?

wolfsbane2k

I was in this boat with externals.
I'd completely gunked up the rd with road crap, gave it a damn good clean off bike, relubed, all ok.
One thing i did was disconnect the rd and put a dot of Sharpie pen on a spot i could measure from, and checked the movement each time.

sloppyschleckonds

Is it electronic? Have you switched it off and back on again?

meanredspider

SloppySchleckonds wrote:

Is it electronic? Have you switched it off and back on again?

It must be because mechanical never goes wrong and is very easy to fix beside the road...

pastryboy

Gear hanger is brand new wheels mfg.

Narrowed it down to rear loop. Kept cutting new bits of shimano cable and trying again but same problem. Tried some lifeline cable and looks to be moving OK now but didn't have time to test - this was done at 4:30 this morning!

It's so annoying there's no logical reason why the shimano cable shouldn't work. It's fine on the other part of the run

thistle_

pastryboy wrote:

Gear hanger is brand new wheels mfg.

Narrowed it down to rear loop. Kept cutting new bits of shimano cable and trying again but same problem. Tried some lifeline cable and looks to be moving OK now but didn't have time to test - this was done at 4:30 this morning!

It's so annoying there's no logical reason why the shimano cable shouldn't work. It's fine on the other part of the run

Is the rear loop too tight, so it's causing too much friction as the cable passes around it? Or too big so it's pushing the derailleur?

Ben6899

pastryboy wrote:

Gear hanger is brand new wheels mfg.

That doesn't guarantee anything. It may still be slightly bent. Or, even if it's perfectly straight on the workbench, how does it look once it's fastened to the dropout?

imatfaal

Ben6899 wrote:

pastryboy wrote:

Gear hanger is brand new wheels mfg.

That doesn't guarantee anything. It may still be slightly bent. Or, even if it's perfectly straight on the workbench, how does it look once it's fastened to the dropout?

This ^.

Get a lifeline hanger straightener - or borrow a Park Tools one. Five mins later, with tiny adjustements, you will have an actually straight not just supposed to be straight rear mech hanger

rick_chasey

£30 and an LBS and make it their problem?

kingpinsam

Doesn't sound like it's related to hangar alignment to me, it's stiction in the cables somewhere, could be swarf or gunk inside the shifter, or the shifter is worn out or damaged, or the BB cable guide is worn.

ben-----

kingpinsam wrote:

Doesn't sound like it's related to hangar alignment to me, it's stiction in the cables somewhere, could be swarf or gunk inside the shifter, or the shifter is worn out or damaged, or the BB cable guide is worn.

I agree. I had the same issue with an old 8 speed Shimano. It was in the shifter; I had taken it apart and probably not put it back together right. But the cable wasn't moving freely/getting stuck.

pastryboy

Have a hanger tool ready to collect and will check but I think it's cable. I tried a very long loop but same issue some shifts do nothing. It does look more promising with the new cable I tried but not counting my chickens.

The outer cable I used had been siting around for years. Shouldn't have degraded should it? As mentioned the bit between shifter and frame entry seemed OK.

jgsi

OK to rule out issues at the shifter end.
I know you got internal routing but
undo at the rear mech .. probably take back the bar tape as well... feed the cable back to the shifter and hold onto it tightly as you click thru on the shifter. You should feel the small increments on the cable as you shift.
If this seems sweet then you can rule out your shifter as the issue at least.

meanredspider

Yup - I would isolate the things that are easy to check.

Nellyspania

New bike

mudcovered

pastryboy wrote:

The outer cable I used had been siting around for years. Shouldn't have degraded should it? As mentioned the bit between shifter and frame entry seemed OK.

Newer shimano shift cables are PTFE coated (anything designed for shifters that route the shift cable under the tape I believe). Older ones aren't. That could be causing the cable to bind somewhere in the frame where a new PTFE coated cable would not.

Edit: Just spotted you said outer. I assume you double checked to make sure it was a gear outer and not a brake cable one? )
Mike

Jal_

Similar issue last week after the bike blew over in the wind. £30 and an LBS and it's now perfect again.

Lazy option but effective.

prawny

I had the same problem on mine, tried loads of different cable inners and outers.

Had to get a new mech because I wanted to get a bigger cassette on and suddenly problem solved. Have you tried new jockey wheels?

antsmithmk

Nellyspania wrote:

New bike

This is the answer

essex-commuter

Nightmare problem, been there a few times. Won't help you but the first time it was the guide underneath the BB, the cable had partially cut through it. Replaced everything bit by bit trying to find what was wrong, ended up being something that cost a quid. Second time I had to replace the rear mech. If it's not obvious I usually work through things cheapest first.

pastryboy

Seem to be getting acceptable shifting now but proper test ride going to happen.

Was the Shimaon cable as per my last comment. I think I tried three different lengths on the RD loop and none of them worked even without ferrules. Last resort was trying the Lifelife outer I had and that worked first time.

Very, very frustrating and no idea why it was a problem other than, as mentioned, I'd had it sitting around for years

mudcovered

pastryboy wrote:

Very, very frustrating and no idea why it was a problem other than, as mentioned, I'd had it sitting around for years

That is a little odd as Shimano gear outers are normally pretty good. Only time I ever have issues with them is if they have corroded inside which normally takes months of riding in rubbish conditions. Hope the test ride goes okay.

pastryboy

The test ride went OK but there were a couple of non-shifts. I cleaned and lubed and when I did a quick check today same problem.

So I ripped out the lot and started again getting rid of the bit of Shimano cable that was between the shifter and frame. Was a bit worried as I had to re-use the same inner which needed a little cutting but just about had it long enough.

Right now it is shifting damn near perfect in the workstand with a test ride tomorrow planned.

I probably had no need to replace the cables at all since the hanger was so bent but I had no reason to assume it'd be bent and assumed it was worn cables.

An educational experience if nothing else.

itboffin

Full length outers if you can fit them or at the very least some coated inners make a huge difference, i fitted up my monster MTB today with full outers and the only adjustment needed was a few low screw turns.

Ive been having horrible shifting on three of my bikes and im pretty sure its cable related

pastryboy

Fuuuucc....

Perfect this morning then noticed it wouldn't shift to the biggest cog at the back on the afternoon ride.

Even with everything replaced I a back to square one - there an upshift and downshift that do absolutely nothing - so I need to shift up twice and down twice for certain changes and at random some downshifts don't happen.

I give up.

imatfaal

Last Ideas I can think of
1. You have a Shimano cable running through SRAM outer - there is only a .1mm difference and I have never had a problem
2. You have frayed off a piece of cable which is stuck in your brifter
3. Your brifter is breaking or already broken (I once had most of the internals fall out of an ultegra brifter at Blackfriars) - Bloke next to me on the cyclesuperhighway "Ooops - that's gonna be expensive" . Is the white plastic disc which takes the cable shifting around crisply and cleanly? You can see this without disassembly - just by removing rubber grip.
4. Your brifters are full of crap.

2 and 4 are remediable by a good clean (I just spray gt85 in through any holes I can find and make sure I have a container underneath

pastryboy

Using a generic cable from wiggle, not SRAM. I blasted GT85 through the shifter which looks to be working OK. I also sprayed GT85 into the cable entry point. If there was anything stuck inside the frame I'd have expected to have pushed it out by now as I've tried so many bits of cable.

Thing is it was working perfectly on the workstand and then it worked fine on the AM ride to work.

It was only come PM that it no longer shifted to the largest cog, when I attempted to alter that via the barrel adjuster I just ended up with more problems.

Nothing should be worn or broken - bike has only done about 2,500 miles in two years and barely seen the rain.

I have bought another bike so at least I can leave this be for a bit then come back to it afresh.

rubertoe

If it was shifting fine on the stand and then fine in the am, but not in the PM, I assume that this has been left in a public place with the great unwashed and their bikes.

I bet the rear mech has taken a knock and the hanger is slightly out.

But buying another bike because its not shifting properly is a bit extreme though, surely that must be the greatest parts sale by a lbs ever.

"No mate you dont need new cables to get that shifting properly. What you need mate, is a new bike. That will sort all your problems."

pastryboy

Underground car park at work - should be fine. Hanger is brand new after I noticed the old one was bent. I don't know how it had got bent and there's nothing visibly wrong with the RD.

Although I said I gave up I have just gone and set it all up again. It is shifting perfectly right now in the workstand. Next ride is Sunday so I'll see what happens.

New bike was a suggestion on page 1 - I'm just doing what I'm advised :oops:

meanredspider

pastryboy wrote:

Underground car park at work - should be fine. Hanger is brand new after I noticed the old one was bent. I don't know how it had got bent and there's nothing visibly wrong with the RD.

Although I said I gave up I have just gone and set it all up again. It is shifting perfectly right now in the workstand. Next ride is Sunday so I'll see what happens.

New bike was a suggestion on page 1 - I'm just doing what I'm advised :oops:

Not a cassette or hub issue? There's no load in the workstand.

It's one of the things that makes me happy about Di2 is that, after doing a change on the bike, you can tune the thing on the fly.

I still think that there's an alignment problem - something bent, worn or loose at the rear. It shouldn't be this difficult (as much as I think mech shifting is so 20th Century).