gear indexing woes

I am struggling to get my rear derailleur to shift to both the smallest cog and the largest

If I lower the cable tension then I can get it into the smallest cog, however, then there isnt enough tension to get it into the largest.

The moment I increase the tension the derailleur moves left slightly and its then impossible to get the chain onto the smallest cog but it will then at least go into the biggest cog

Any ideas??

(shimano ultegra 6800)

Hi are you sure your shifters are as should be, if yes, limit screws may need a tweek

limit screws are correct I believe. Without any cable tension at all it sits on the smallest cog and I can push the derailleur into the biggest cog.

Shifters?

are the shifters compatibile with the cassette,

yes - its full shimano ultegra 6800

I would now try adjusting the limit screws with cable connected

Your rear mech arm is bent or slight play in it. That was my problem. I lent it against something when i put it the boot of my car for a while.... After that it would only shift in top 8 gears or bottom 8 depending on how i tensioned it. Drove me spare.

The cable might be routed around the wrong side of the clamp screw on the derailleur.

When you adjust it so you can get the smallest cog is the shifting better over the 3 or 4 cogs at that end of the block than the 3 or 4 at the other end?

Vice versa, if you adjust it to get the biggest is the shifting better at that end?

If so, the hanger is bent.

It is currently set up so it can shift into the smallest cog

In the stand, as you are coming down the gears (to the smallest) they all click through, until you get to the smallest where it takes two clicks to get in. Feels quite smooth until that point.

When you are riding though it just feels pretty rough and doesnt change gear, seemingly at any point in the block, will check on my ride home if its towards any particular end of the block.

Your shifters and cassette are mismatched. There shouldn’t be 2 clicks left.

I had the exact same problem a week or two back, problem was I needed a new chain as mine hadn't been changed since I first bought the bike. Not entirely sure this info helps as I don't know the back story but worth a try

Check for worn or frayed shifter cable

Im certain I shifted to the smallest cog (clicked through over 11 times) before tensioning the cable, will double check though and re-do.

If that's what you mean

11 speed should only have 10 clicks.

I just meant you you know when you want to make sure its in the highest gear you just keep clicking

as far as I can recall there has never been a time when you cant keep clicking at the end, it just does nothing, obviously.

undo the cable at the derailleur end. it should fall in to the last gear when it has no tension.

if it doesn't theres a problem with the derailleur.

if it does then it's likely the cable, either its too tight or needs replacing as its getting fouled up somewhere.

Ok yeah I see what you mean. If that 11th click is releasing any cable though (and presumably it is if it allows the shift to happen) then something is up.

limit screws are correct I believe. Without any cable tension at all it sits on the smallest cog and I can push the derailleur into the biggest cog.

Shifters?

Just noticed this post, this would suggest something amiss with either cable or shifters yeah.

I'd say cable was the more likely.

If the cable is catching somewhere, be that due to corrosion, routing or damage, it could be that the shock from the ratchet mechanism clicking in the shifter is enough to sort of bump it through a bit more.

Cabling under the bar tape would be were I'd look first. How old is the set up? Have you replaced the inner and/or outer cables since new?

Be sure to post the answer please

Can confirm all clicks move the derailleur - currently not to the biggest cog. 9th click moves it half a shift towards smallest, 10th click the rest.

Looking at cable next

Solved

Was definitely something to do with the cable, I undid bar tape, did some technical jiggling of cable, pulling it in and out of shifter, through internal routing etc whilst cable wasn't clamped.

Think I might have pulled through a mm of extra inner cable?

Works now

Thanks!

Your cable sounds like it is frayed inside the shifter

Is it shimano by any chance?

Cable fray was exactly the reason why I had to replace my old cable, was frayed so bad it snapped in half.

This cable is only 6months old though and looks okay in the shifter, the other was a year and a half and looked like below.

Is this a shimano thing?

1 Attachment

Push it back out at the shifter and check

Put rear mech into largest sprocket, then shift to the highest gear without pedalling. This will give you enough slack to disengage rear mech outer from the boss on the frame.

Now you have slack cable to push it back out at the lever