Shift up Indexing

mitchgixer6

Hi all,

Had some probs with my indexing recently which I managed to sort by setting "H" + "L" screws, as well as cable tension. All seemed well until last night. Was out for a run and my rear derail is now shifting down (to largest cog) OK, but going up is taking about 3 seconds to engage. If I get inptient and double shift it will shift 2 cogs straight away. Any ideas as the indexing the other way is spot on.

Cheers

Bhima

If you release the cable completely, the derailler should return the chain to the smallest cog; it's natural position - so when you shift to a smaller cog, you're just releasing more cable to allow the derailler to move closer to its natural position. When you shift to a larger cog, the cable is pulling the derailler up, so perhaps the cable has stretched a bit or there's some dirt inside the cable housings, causing resistance.

Get a new cable and see if it'll work. If it doesn't, you have a spare cable.

This is usually the first sign of cassette wear too. Happened to me the other day on one particular cog - which I may replace...

k-dog

The mistake you made is that you adjusted the limit screws when you had an indexing problem - the indexing is fixed by the ratchet in the shifters and the only thing you need to adjust is the tension on the cable - usually with a barrel shifter.

I would suggest starting again with your bike on a stand or at least in the air.

Put the shifter in the smallest cog position and check the high and low limits by pulling the cable with your hand (under the downtube is best).

Then adjust the cable tension by turning the barrel adjusters so that the change up and down is as good as it can be - it's a balancing act getting the tension in the middle so they go up and down equally well.

Parktool.com has good instructions if you need help.

Cable stretch affects up and down shifts in the same way so it isn't that - it sounds like your tension just isn't quite right.

markos1963

+1 for cable stretch as well. Leave those limit stops well alone, unless you like the idea of wrapping your mech up in the wheel! Also a lot of shifting up(towards the small cogs) problems are caused by crud in the cable outers and around the BB area, as Bhima says, get a new cable and give that a go paying particular attention to cleanliness when installing.

mitchgixer6

Lovely! Thanks for the hints folks. I did move the limit screws when I was messing about, so will double check them along with the tension.

Thanks again.