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Really struggling to get my gears indexing properly. I can get it to shift up the cassette ok til about the 4th gear up, then I have to "trim" it up to that, after that it's generally ok getting to the top of the cassette. Going back down it takes a few clicks before it'll shift down then clunk to whatever gear it's shifted to. It's a Shimano Deore M5100 rear mech with a Sunrace 11-51t cassette. Hanger looks to be straight by eye but hard to tell. The cassette is possibly a bit worn and I'm tempted to swap it anyway for peace of mind, but generally can a worn cassette cause such issues anyway? Bought the bike used and the chain was past .75 stretched when I got it, have replaced chain a while ago but the damage may already been done. The cable was swapped to a full length SP41 not long after I got the bike and it doesn't seem to be binding anywhere so don't think it's cable related.
Any suggestions before I chuck it in the bin and go singlespeed?
The hangar would be the first thing I'd check, then go from there.
I'm going with hanger too.
How does the B screw adjustment look? Chain length? If either are off, you'll get similar problems.
My frame/hanger match the Shimano 12sp spec I don't think. I can't get the line to align with the teeth. Still shift ok but it takes a bit of fiddling to get it there.
Check alignment. Put a steel/plastic ruler against the side of the sprocket and check the derailleur is aligned with the ruler, sounds like it may be bent slightly? Next swap/check the hanger and worth putting a new cable in just to check.
I had this issue earlier in the year, tried and checked everything, just couldn't get it smooth and reliable. I'd ended up shearing one of the little slots that holds the pawls in the freehub body, so it was pulling slightly off true. Over time the cassette had ended up on the squint.
Obviously rule out typical stuff first, but if everything is straight, then check the freehub isn't running wonky.
That style of deore mech can be just as finicky as a 12 speed one.
I fitted one to my nephews near bike build a few years ago - on a brand new Brand X frame (which was the previous gen Vitus Sentier I believe).
Couldn’t get the indexing right in the middle of the cassette so I borrowed a tool for checking / fixing the mech hanger straightness. It was off a bit - 1 quick tweak and mech back on and it was perfect.
If it’s not that it could be a bent mech cage.
You say the cable was changed not long after you got the bike
Is the cable routed into, and round the rear mech properly?
it should route around the pinch bolt from nearest the cassette. Does that make sense?
if its the other way round you can get those shifting issues
If you're confident that the cable isn't the problem, including at the lever, then it has to be the mech
Check the alignment of the hanger, B-screw and mech cage (as above) and that the G and T jockey wheels are the correct way around (T-tension to the bottom)
Check that the cable is routed to the clamp correctly and if everything is aligned take the mech off and give it a good clean and lube
Check the hanger isn't bent or twisted.
It probably is, that's where 90% of these "it's indexed ok at one end of the cassette, but not at the other" problems are solved.
Hanger alignment, B-screw setting, cables.
The other thing I've had issues with in the past, is excessive jockey wheel sideways play in the guide - upper - pulley, even when the wheels still have plenty of tooth left on them. Shimano jockeys start off with some sideways play anyway and it's quite possible for wear to leave you at a point where there's so much sideways movement, that when you try to shift, the jockey wheel slack is enough that the cage can move without the jockey being pushed far enough over to shift the chain. It'll shift cleanly one way, under tension because the wheel is pushed right over, but not the other ime.
I don't know if that makes sense, but it's easy enough to change the jockey wheels and sort it instantly if that is the issue. It's happened two or three times to me, when everything else has been perfect. Maybe worth a try if the upper jockey seems to have a lot of sideways play.
either going to be hanger or wheel bearings
Piggy backing on this thread - what, preferably inexpensive, mech hanger checker are you all using?
Piggy backing on this thread - what, preferably inexpensive, mech hanger checker are you all using?
Good question, I'll watch the answers with interest as I have a new 11-speed setup (XT) which shifts fine up to about 9th gear and then requires some jiggling to get it to 9/10/11 properly.
These are supposed to be good but you'll have to wait for shipping from China. https://escapecollective.com/ztto-hag-5-derailleur-hanger-alignment-gauge-review/ (ZTTO HAG-5)
I own one, haven't had to use it yet but should be doing so this weekend as my shifting is off after doing a full strip last weekend - should have checked alignment then but I was against the clock so skipped it.
Thanks everyone, hopefully can hold off getting a new cassette for a little while then! I did wonder if my b-screw was off as it looks a little high, but it work go any closer to the cassette at the minute, possibly too short a chain causing that?
Might order one of those ZTTO hanger tools, I'm not in a massive rush as I don't ride that often so can wait for the postage!
I've got an older, slightly different ZTTO hanger tool and it's been fine. I think it was a tenner.
That HAG-5 looks loads better though.
if everything is aligned take the mech off and give it a good clean and lube
i fitted a new cable and outer and checked the hanger alignment of my wife’s bike. Still couldn’t get it shifting right. I decided to blast it with a can of clutch cleaner which sorted it straight away. Turns out it just needed a clean 🙄
I've got an older, slightly different ZTTO hanger tool and it's been fine. I think it was a tenner.
That HAG-5 looks loads better though.
I've got a HAG-3 and modified it with a tapped hole and thumb screw to clamp the measurement rod. Which is effectively what they've done with the 5, so I'm happy with that.
I've got one of those HAG5 tools.
Works very well despite it's low cost.
I wasn't expecting a lot when I ordered it but was very pleasantly surprised with the quality of it when it arrived.
Used my ZTTO this morning, good bit of kit and much better than the toopre park tool knock off it replaced. Hanger straightened.
Had very similar recently, annoyed me, bought new cassette, even chain .. it was the hanger :/
I've had the X tools version for a few years now. Easy to use, works a treat TBH. There seems to be quite a few versions of the same tools out there all looking pretty similar apart from the badge.
Is this where the axs lovers should be suggesting to upgrade to wireless as this hardly happens? Assuming it isn't a bent hanger or worn teeth then that could work - but is costly...and if there is an alignment issue then spending on that won't actually help.
Drivetrain is all very clean and chain is lubed? Cables reasonably recent, clean and smooth moving? Have you considered replacing the mech hanger (assuming it is replaceable)?
The mech itself isn't twisted or the lower cage bent?
If the problem is that you cannot get it to work all across the cassette, but it will work in different spots, nine times out of ten it is the hanger.
A hanger alignment tool is your friend here - even if you aren't going to use it to straighten a hanger, it is great for diagnosing that the hanger is the source of the problem.
Maybe a move back to thumbie's 😆
If the problem is that you cannot get it to work all across the cassette, but it will work in different spots, nine times out of ten it is the hanger.
A hanger alignment tool is your friend here - even if you aren't going to use it to straighten a hanger, it is great for diagnosing that the hanger is the source of the problem.
This is great advice!