Rear Mech adjustment

funkey_monkey

Hi,

I've been trying to adjust my new rear mech setup and struggling to get it to index correctly.

At this stage the cable has stretched after installment, so should just need a tweak. The issue is currently when indexing from 5 -> 6 (6 speed freewheel) it can take a number of revolutions to shift or may not shift until I index from 4 directly through to 6.

I've consulted the Shimano tech doc and the guide for fine adjustment is causing me some problems:

http://techdocs.shimano.com/media/techdocs/content/cycle/SI/SI_5WU0A/SI-5WU0A-001-00-ENG_v1_m56577569830701975.PDF

Firstly, in the diagram they talk about 2nd and 3rd sprockets - inferring that 1st sprocket is the smallest. Whereas the shifter on my bike is reversed (1st is largest sprocket). I've assumed that the diagram is correct and the confusion is with the wording. Hence, I'm adjusting based on what I consider to be 4th and 5th sprockets.

Anyhow, when I make the adjustments so that that the chain is sitting on the sprocket as close as possible to the inside sprocket, as per the instructions, it really reduces the ability of the mech to shift correctly outwards. I've adjusted it so that the mech shifts correctly unloaded on the stand, but when I'm cycling, the behaviour is different in that the mech will travel inboard correctly but when travelling outwards, there can be a delay of up to 4 -5 revolutions or indeed no shift. This is not consistent behaviour as sometimes it works and sometimes not.

What adjustment am I'm missing?

Wicklowrider

If you have correct shifting on the other sprockets , you are probably close.
Are you adjusting now from the barrel adjuster?

Watch this - its ten speed but the principles are the same.

http://www.youtube.com/watch?v=wQncKmddahk

shedweller

Have you checked cable tension. I find that if it is too high the shift action from low gears to high tends to be slower. It shifts down too well also and almost overshifts. Remember the derailleur spring has to overpower the cable tension.

funkey_monkey

It's difficult to estimate 5kg - 10kg of tension during assembly.

Thanks for that video. @2:10 is he not saying the opposite of the techdoc I linked to? He is setting up so that the mech is "barely inboard", whereas the techdoc is equivalent to 'barely outboard'?