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[Closed] What's wrong with the shifting on my rear mech?

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In summary the issue is as follows.

Rear mech takes 2 shifts to get moving in either direction. What I mean by that is if I want to shift up the cassette I need to click twice for the first shift, then it’ll click up the cassette perfectly (one shift per click)

Then when I want to go down the cassette, again it takes 2 shifts before it again starts shifting perfectly down the cassette again

New cable and outers, limit screws seem ok.

What’s going on?

It’s 10 speed 105 with bar end shifters if it makes any difference?


 
Posted : 06/02/2022 10:12 pm
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Do ypu have the full range of sprockets? For example, if you start in the smallest sprocket, will the derailleur go all the way up to the 10th sprocket? If not, then it could be slack in the shifter cable, which is easily adjusted with the barrel adjuster or just undoing the pinch bolt, pulling the slack through, and nipping up tight again.

The fact youve mentioned new cables suggests its been dismantled recently? Could there be slack in tbe cable due to the pinch bolt not being as tight as you thought on reassembly and the cable pulling back through slightly under tension?
The double clicking could be the ratchet taking up the slack / backlash, then once the slack has been removed the mechanism has enough tension to shift as intended.
This is the first thing I'd check by putting it into the small sprocket and pulling the cable through til you feel tension and nip down hard on the pinch bolt.


 
Posted : 06/02/2022 10:21 pm
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The first thing I'd check is that the cable is attached to the rear mech correctly.


 
Posted : 06/02/2022 10:27 pm
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Worn cassette? Just replaced inner and outer cable tonight and previously replaced chain ring, cassette and chain and shifting like a new bike now. Do the your mech spring not worn or sticky?


 
Posted : 07/02/2022 12:07 am
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As Johnnymarone says could well be slack in the cable that you are having to take up on initial shifts. Going from larger to smaller sprockets on the cassette suggests that the spring in the mech isn’t overcoming the lack of tension in the cable, ie the cable is holding the mech back and not allowing the mech to move.

This could be cable related. You’ve fitted new cables? Did you make sure the cut ends of the outer aren’t squashed from the cutters? Is the outer securely inserted into the ferrules? Are the ferrules tight on the cable? Are the ferrules in the mech and shifters correctly?

Without the chain on and the cables in and tightened does the mech swing freely and does the springs seem strong and firm?

If all of that is OK it’s down to the basics. Mech hanger alignment?


 
Posted : 07/02/2022 7:53 am
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There was a guy on here last week who had similar problems and it turned out to be a goosed jockey wheel bearing.


 
Posted : 07/02/2022 8:45 am
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That was me, top jockey wheel bearing was all over but my shifting up was perfect and only issue was getting off the 46t


 
Posted : 07/02/2022 8:52 am
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I had to force mine across recently and the correct diagnosis from here was B screw tension - top jockey wheel was too close to the cassette.


 
Posted : 07/02/2022 8:59 am
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Are you absolutely sure the cable is seated properly at the shifter end? If the shifter wasn't aligned properly when you fitted the cable it can cause all sorts of issues.


 
Posted : 07/02/2022 8:59 am
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First thought. Cable is clamped the wrong side of the pinch bolt on the rear mech.


 
Posted : 07/02/2022 8:59 am
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Bar end shifters...no expertise on these but will comment anyway but you might might want to bump the thread every few replies with a Bar end shifter related statement in the biggest font can find! and hopefully an expert turns up
My understanding is that depending on position when cable removed it is pretty easy to upset the indexing

^^^someone suggested slackening the cable clamp bolt on rear mech and taking up any cable slack...I'd try releasing the cable clamp bolt and pulling on the cable whilst returning the shifter to the "slackest" position...that is making sure the shifter is starting from where it should and then taking up any slack


 
Posted : 07/02/2022 9:02 am
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Interesting point on Jockey wheels, my winter bike (105 11sp) no longer shifts very crisply - have tried all the usual stuff.

Are jockey wheels model specific or will any Shimano jockey wheel set do (no idea what model number by derailleur is)?


 
Posted : 07/02/2022 9:54 am
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Have Shimano fixed their jockey wheel compound now then or am I reading it wrong thinking folks had dead bearings on Shimano mechs.

Used to be that in markedly similar time frames, bearings were the mode of failure on SRAM, on Shimano it was the wheels turning into ninja stars.

OP of I'm reading it right, your experience sounds very much like mine with a worn cassette and chain, no slipping, shifts perfectly when it did shift but takes a few clicks to react sometimes. (Though the double/triple click required to move the mech did result in the appropriate number of shifts when it went)


 
Posted : 07/02/2022 10:02 am
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Are they Shimano Bar end shifters or Microshift? I've had some difficulties with a Microshift 10 speed bar end shifter not finding the difference between two gears in the middle of the range, I assume slightly worn indexing.


 
Posted : 07/02/2022 10:03 am
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Right, I’ve tried everything, made some progress but not much.

All cables and inners are new, ferrules all snug. Cable attached correctly. Shifters are brand new. I now have it shifting up and down perfectly in biggest 3 cogs, however as soon as I get below that I just can’t index it correctly so it moves both up and down with one click

I’m thinking bent hanger, so I bought a new one, but still no progress. So now I’m thinking maybe a bent frame as the shifting has always been a bit iffy on this bike, although certainly nowhere as bad as now

Only other variable may be the rear mech which is an oldish 105 5700. But it worked grand on the bike I took it off, and the it all seems tight enough with no excess play

I’m thinking it’s time to take this to the professionals as my money is on the frame somehow being out of alignment.


 
Posted : 18/02/2022 8:22 pm
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Third to suggest it's how you have attached the cable to the rear mech. Easy to get wrong.


 
Posted : 18/02/2022 8:48 pm
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New hanger isn't necessarily straight. So check the alignment.

My first guess would still be cable routing into the pinch bolt.


 
Posted : 18/02/2022 9:02 pm
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Classic bent hanger. New one doesn’t mean straight.

Is the 5700 series mech compatible with the bar end shifters? The same speed doesn’t mean compatible.


 
Posted : 18/02/2022 9:10 pm
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Yep the shifters are the dura ace sl bs79. I think only tiagra 4700 aren’t compatible with all the other 10 speed stuff

I’m 99% sure the cable is correct. From looking at the shimano docs at least.

Which leaves the hanger. Fingers crossed it’s not that far as as i hear bending them back into shape means they are more prone to snapping


 
Posted : 18/02/2022 10:44 pm
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What range cassette are you using and is this a GS or SS 5700 mech?


 
Posted : 19/02/2022 12:50 am
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Aa above. Tune it up, then replace stuff logically if still happens because worn gear doesn't work as well as the fresh stuff.


 
Posted : 19/02/2022 12:53 am
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Is the cassette loose on the freehub? I had a similar shifting issue once and it was because the cassette lockring had worked loose and the cassette could move from side to side a tiny amount.


 
Posted : 21/02/2022 11:16 am

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