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Third time I’ve typed this before it refreshes the mobile page!!
When indexing I can’t get to top cog (42), and when I give cable tension to make it up their I can’t then get the bottom cog. All clean, some new, nowt bent. What gives? Chain too short?
Anyone?
Limit screws? Can they be backed off a little without going too far? What rear mech, cassette and chain?
did it work before, or is it new kit?
Yeah worked before fine. Should be better now with new outer and inners.
XT cassette and Mech.
I’ll double check I’ve not gone too far inward on the low screw but I’m sure I had it close to the spokes.
Is the mech hanger bent?
Nope. Looks Bob on.
It might look straight to the eye but it might not actually be straight. There’s a tool to check it which is worth doing.
Will the mech move by hand to the highest and lowest positions it need to get to without the cable attached? If not then there’s something going on with the mech / limit screws etc. If it works like that but not with the cable attached then it’s either shifter or cable related.
Yeah I can push it all the way over with no cable tension.
I presume then, as it’s a bit clicky when I get it over to the top cog, that the limit screw is too far inward?
Would chain length be a factor?
I normally set the high and low screws up before connecting the cable to the mech. Turning the pedals and slowly going through the various cogs in the cassette.
Is it 11 or 12 speed? 12 speed is way more picky about b screw and chain length. The chain should be done to the exact Shimano length - they have a diagram online about how the chain sits and how many full links to add.
If you’ve got high and low right and the chain sized accurately then all you’ve got left is cable tension and b screw.
For b screw there is a mark on the back of the jockey wheel cage above the higher jockey that should align with the teeth of the biggest cog when you are in that lowest gear.
If you still can’t get the indexing right it has to be gear hanger or a cable / shifter issue.
11 speed. Can’t see what problem the shifter would have as it seems to work flawlessly. It’s a reasonable new frame so perhaps it’s bent but not enough to the naked eye but enough to cause a problem.
It’s gone on to a Boost frame from a normal frame.
See if you can back out the limit screw a little on either end. Even a quarter or half a turn might help. Obviously be very careful and always make sure it isnt possible to push it into thespokes or frame.
Have you double checked the cable routing on the mech? Silly mistakes like clamping the cable on the wrong side of the bolt can cause all sorts of shifting bother - ask me how I know....
Ok I’ll give pushing the limits a bit further out a little a go. I’ve never felt more inept around a bike since starting to do basic spannering around my bikes. Soooo frustrating as it’s shifting sweet otherwise.
Is there a wrong side of the bolt, the purist?
Mine is coming out in the side nearest the cassette.
I’m pretty much at the end of my tether. Repeating the same process with no change is a sign of madness right?
Is there a wrong side of the bolt, the purist?
Yes, there is on all mechs
Yes, there is on all mechs
theres usually a groove on one side next to the bolt, to show where the cable should sit.
Wear in the rear mech pivots making the mech sloppy.
Jockey wheels worn.
Check B screw is screwed in enough so the too jockey wheel is only a couple of mm's off the largest cassette cog.
Knackered gear cable and/or outer.
11 spd xt cable enters at the top, runs down the cassette side of the clamp and exits pointing down or towards the limit screws
I had this on my old Soul and ended up buying a new rear mech, mech hanger and gear cable. It cured it.
Loose mech hanger.
Bent mech hanger.
Loose mech bolt.
Loose cassette.
Gear indexing.
Wheel not sitting in the dropouts properly.
Loose rear wheel quick release.
Knackered wheel/cassette bearings.
11 speed cassette with everything else being 10 speed. Happened to a pal.
New cable and housing. Mech looks ace, cassette fine and solid, chainring is ok, though I reckon ovals are more noisy, hanger looks fine but could be bent so little I can’t see it, will check the cable exits correctly out of the pinch bolt. I’ll check wheel is in right but it looks true and it’s pretty difficult to incorrectly seat a bolt-through. Limit screws are at the limits. I either dial enough cable in that it shifts perfectly from 11th to 2nd or dial out enough that it goes from 1st to 10th.
I can hold the trigger shifter in and it stays in the top cog but as soon as I let it go it drops to 2nd.
Bent mech hanger. Have you checked it with a hanger alignment tool? The more sprockets on a cassette the fussier the alignment needs to be.
No I’ve not checked within a tool, don’t have one, so LBS will be next stop.
Where are you? Someone might be able to help out rather than pay your LBS.
Mech hanger checked with a tool?
Mine have always 'looked' straight, some of them have been miles out when I check with the tool.
New bikes are often not perfectly aligned, I always check any bike I get my hands on.
Chainline out having gone to boost?
Possibly a stupid question (but I have to ask, as i've seen it done),your shifter was actually in highest gear, not 10th, when you connected the cable to the mech?
+1 for bent hanger, mech alignment tool is best investment you’ll ever make if you do your own gears.
And a 🤬 +1 for making sure the shifter is in the right gear when you attach the cable 😂😂
If you don't have a tool do you have an old qr style front wheel? The thread on a Shimano cup and cone wheel is the same as the mech hanger. You can remove the derailleur and screw the wheel in. They should be parallel.
Shifter is fine. In fact I don’t think you can get it into the housing unless it’s in highest gear - and I’ve started from scratch a number of times and not clicked a gear when attaching to mech.
Boost chain line could be a consideration? There is one 1mm spacer behind the cassette and I have 1 spacer on the drive side bottom bracket with a 34t chain ring.
Have you clamped the cable with your bike stand? Easily done on old bikes with exposed inners but I’ve also found that outers can be slightly squashed enough to impair the inner when shifting.
No, internal routing and clamped on the seat post.
I'm having similar issues with GRX on an 11-40 cassette.
I've improved matters slightly by backing off the clutch friction, I tested shifting with clutch on and off and it was noticeably better with clutch off. Adjusting clutch friction was easy enough.
I used to adjust B-tension to keep jockey wheel as close as possible to cassette, but it seems on wide range cassettes you actually need to keep it further away, mine works best with quite a lot of B-tension.
Still not perfect but I haven't checked hanger alignment recently so will give that a look before I just heave the lot into the sea and go back to 10 speed with a sensibly sized cassette...
Well I’ve booked it into the LBS. it’s either needing a bigger spacer behind the cassette, straightening of the hanger or the chain is too short. Whilst the 32t chainring isn’t boost it’s got plenty of clearance and chain line looks ace.
LBS in the morning. Hopefully it’s cheap to sort.