Gear Indexing Issues

portland_bill

Morning all,

I've got a proper head scratcher here. A work colleague of mine has asked me to try and sort his gearing out for him, but I've tried everything, and I can't get them to index properly.

He has Shimano 9R 3F Alivio shifters, with a Deore rear mech, and Acera front mech. The problem is with the rear shifting.

I've loosened the cable, set the limit screws, tightened the cable back up again, then tried to climb down through the gears, but it gets to 8th, and needs two clicks to get onto the 7th gear, so I turn the adjuster until it climbs onto the gear, and progress through the rest of the gears fine. However, when I then try and go back up through the gears, it gets to 8th, and will not drop onto the 9th gear without me turning the adjuster back in, which then stops it from going back down the gears again.

I've cleaned the cables outers, and put a new inner on for him, but it's still doing the same thing, so I'm at a bit of a loss as to what else could be causing the issue.

Appreciate any help!

Cheers

K

The Rookie

Is any part new from when it did work?

Bent hanger is possible but unlikely for that issue

reaperactual

Undo the inner cable anchor bolt, hold the inner in your finger tips and feel for clean, frictionless in and out movements as you shift up and down the whole gear range and also ensuring the shifter is not the issue, rare but not impossible.

Meanwhile push and release rear derailleur to check for free movement, jockey wheels, particularly the top jockey wheel for acceptable lateral float but not sloppiness or twisting movement.

Your symptoms sounds similar to what happened to me because I had gone way too far in one direction or the other with the fine tuning and totally lost any idea of where I was and which way to go.

Worth starting again making sure the shifter is definitely in 9th gear, the inner barrel end is seated properly before fixing inner along the groove under the anchor bolt, fine tune knob all the way in and back one full rotation and restart fine tune process again.

steve_sordy

All of the above advice is good.
Check that the mech hanger is properly bolted to the frame. Ditto the mech to the hanger (both of those have caught me out).

When I have had seemingly intractable shifting problems and none of my usual tactics work, then I suspect the mech hanger alignment. Once you have the alignment tool it is a ten minute fix. You probably don't have one, so either borrow one or take your bike to the LBS and ask them to align the mech hanger. It will not be expensive, because it is so quick to do.

But if your bike shop is anything like as busy as the ones near me, it will be quicker to buy a mech hanger and DIY!

giantorangedale

Youtube, Calvin Jones, park tool, gear indexing, sorted.

ed1973

All great advice. I would start at the top and work my way down to eliminate problems.
Is the shifter clean and greased inside?
You say you have changed the inner but change the outer as well.
Deffo make sure your shifter is clicked to the highest (smallest cog) gear.
Work your way through the indexing steps mentioned by @reaperactual
If this all fails, I reckon it’s a misaligned mech.